JP5510066B2 - Determination of total phosphorus - Google Patents

Description

  The present invention relates to a method for quantifying total phosphorus, and in particular, quantifies the total phosphorus in test water by decomposing the phosphorus compound contained in the test water and converting it into phosphate ions and then quantifying the phosphate ions in the test water. Regarding the method.

  Phosphorus is one of the causative substances related to eutrophication such as ocean water, lake water, river water, and groundwater, so there are regulations on the discharge of factory wastewater. Quantification of phosphate ions is required before discharge. Here, factory effluents not only contain phosphorus as phosphate ions, but may also contain phosphorus elements as various phosphorus compounds. Phosphorus compounds are naturally decomposed after being discharged into the environment, which is the source of phosphorus. It becomes. For this reason, factory wastewater and the like may be required to determine not only phosphate ions but also the total amount of phosphate ions including phosphate ions that can be generated from phosphorus compounds, so-called total phosphorus. And, with the increase in environmental conservation, the quantification frequency of total phosphorus in factory effluent and the like is steadily increasing, so an automated apparatus for the quantification work is desired.

  As an official method for quantifying total phosphorus contained in water, molybdenum blue (ascorbic acid reduction) absorptiometry described in Non-Patent Document 1 is known. In this quantitative method, a heteropoly compound produced by reacting phosphate ions contained in water with hexaammonium heptamolybdate and potassium antimonyl tartrate (dipotassium bis [(+)-tartrate] antimony (III)) is produced. Phosphate ions are quantified by measuring the absorbance of the test water colored by molybdenum blue produced by reduction with L (+)-ascorbic acid.

In the determination of total phosphorus by molybdenum blue (ascorbic acid reduction) absorptiometry, first, a predetermined amount of test water is collected, and pretreatment is performed to decompose the phosphorus compounds contained in the test water and convert them into phosphate ions. . In this pretreatment, after adding a potassium peroxodisulfate solution, which is an oxidizing agent of a phosphorus compound, to the test water, the test water is treated in a high-pressure steam sterilizer set at 120 ° C. for 30 minutes to oxidize the phosphorus compound. Decomposes and converts to phosphate ion. Next, a predetermined amount of ammonium molybdate-ascorbic acid mixed solution is added to the pretreated test water, shaken, and then allowed to stand at 20 to 40 ° C. for about 15 minutes. Then, the absorbance at a wavelength of about 880 nm is measured for this solution, and the phosphate ion concentration (mgPO ₄ ³⁻ / liter) of test water is calculated based on a calibration curve prepared in advance from this measured value.

  The pretreatment of the test water in such a total phosphorus quantification method requires the use of a high-pressure steam sterilizer, that is, a pressure-resistant container, which complicates the operation and requires special safety. In addition, potassium peroxodisulfate used as an oxidizing agent needs to be used in an excessive amount because it decomposes the phosphorus compound at the same time as oxidative decomposition under a temperature environment of 120 ° C. and also proceeds with autolysis.

  Therefore, as a pretreatment method that replaces this pretreatment method, Non-Patent Document 2 proposes a method in which potassium peroxodisulfate is added to test water and then treated at 100 ° C. for 60 minutes. However, in this method, a portion of potassium peroxodisulfate remains in the test water, which may inhibit the reduction of the heteropoly compound by L (+)-ascorbic acid, so the ammonium molybdate-ascorbic acid mixture Before adding the solution, the test water is allowed to cool to 20 to 40 ° C. to suppress the oxidation action of potassium peroxodisulfate, or sodium sulfite as a reducing agent is added to the test water in an alkaline state to add peroxodisulfate. It is necessary to extinguish potassium sulfate.

  However, when the oxidation of potassium peroxodisulfate is suppressed by allowing the test water to cool, it takes a long time to cool the test water, making it difficult to complete a series of quantitative operations in a short time. In addition, when sodium sulfite is added to extinguish potassium peroxodisulfate, harmful sulfur dioxide gas is generated. Therefore, safety measures are required.

  In addition, the ammonium molybdate-ascorbic acid mixed solution used in the above-described method for determining total phosphorus is composed of hexamolybdate hexaammonium tetrahydrate and potassium antimonyl tartrate trihydrate (molybdenum blue production reaction accelerator). A solution of ammonium molybdate prepared by dissolving sulfuric acid and ammonium amidosulfate (a decomposing agent of nitrite ions that interferes with the formation of molybdenum blue), and an L (+)-ascorbic acid solution are dissolved in water. It is necessary to prepare by mixing the ammonium molybdate solution and the L (+)-ascorbic acid solution at the time of use.

  Here, the L (+)-ascorbic acid solution is an aqueous solution prepared by dissolving L (+)-ascorbic acid in water, but the deterioration of L (+)-ascorbic acid proceeds rapidly after preparation, It changes in quality (appears discolored to yellow). For this reason, Non-Patent Document 1 instructs to store the L (+)-ascorbic acid aqueous solution in a dark place at 0 to 10 ° C., and prohibits the use of colored ones. As described above, the L (+)-ascorbic acid solution has a limited storage environment, and it is necessary to confirm the presence or absence of coloring during use. It is.

  Further, as described in Non-Patent Document 1, the quantification method for total phosphorus is a trace amount range of 1.25 to 25 μg, so that the test water contains a relatively large amount of phosphate ions and phosphorus compounds. There is also a problem that it cannot be applied in some cases.

Japanese Industrial Standard JIS K 0102, Factory Wastewater Test Method (2008) 46.1.1 and 46.3

2002 Ministry of the Environment contract work result report, water quality analysis method study investigation, pages 5 and 13

  An object of the present invention is to enable the total phosphorus of test water to be quantified safely and in a short time.

  The present invention is a method for quantifying the total phosphorus of test water by decomposing the phosphorus compound contained in the test water and converting it into phosphate ions, and then quantifying the phosphate ion of the test water, Step 1 in which an alkali metal salt of peroxodisulfuric acid or ammonium peroxodisulfate and sulfuric acid are added to water and heated for a predetermined time at a temperature from 65 ° C. to the boiling temperature of the inspection water, and the inspection water passed through step 1 has 5 carbon atoms. A first aqueous solution containing a saccharide selected from the group consisting of an aldose, an aldose having 6 carbons, a ketose having 6 carbons and an oligosaccharide capable of producing a aldose having 6 carbons or a ketose having 6 carbons by decomposition. Subsequently, the oligosaccharide which can produce | generate 6 carbon aldose or 6 carbon ketose by decomposition | disassembly with respect to the test water which passed the process 2 which followed the predetermined time heating, and the process 2, 7 molyb Step 3 and Step 3 in which an alkali metal salt or alkaline earth metal salt of molybdate or an alkaline earth metal salt of molybdate and an antimony compound having an antimony valence of 3 or 5 were added as an aqueous solution and maintained at 65 ° C. or higher. Step 4 of measuring the absorbance of an arbitrary wavelength in the range of 600 to 950 nm for the test water.

  The oligosaccharide used in this quantification method is, for example, sucrose, maltose, lactose, raffinose, kestose, stachyose, isomaltulose or lactulose.

  In one form of this quantification method, in Step 3, an oligosaccharide, hexammonium heptamolybdate or an alkali metal salt or alkaline earth metal salt of molybdic acid and an antimony compound having an antimony valence of 3 or 5, Add to test water as second aqueous solution. The oligosaccharide contained in the second aqueous solution is preferably a non-reducing oligosaccharide. This non-reducing oligosaccharide is, for example, sucrose, raffinose, kestose or stachyose. In a modification of the quantitative method of this embodiment, the second aqueous solution is used as the first aqueous solution.

The present invention according to another aspect relates to a color former for color development of phosphate ions contained in test water, which is used for quantifying total phosphorus in test water by the total phosphorus determination method according to the present invention. The phosphate ion colorants include oligosaccharides capable of producing 6-carbon aldoses or 6-carbon ketoses by decomposition, hexaammonium heptamolybdate or alkali metal or alkaline earth metal salts of molybdate, and It consists of the aqueous solution containing the antimony compound whose antimony valence is 3 or 5.

  The oligosaccharide used in this color former is usually a non-reducing oligosaccharide. This non-reducing oligosaccharide is, for example, sucrose, raffinose, kestose or stachyose.

  Since the total phosphorus quantification method according to the present invention includes the above-described steps 1 to 4, the total phosphorus of the test water can be quantified safely in a short time.

  Further, since the phosphate ion colorant according to the present invention comprises an aqueous solution containing the above-described components, it can be easily applied to an automatic quantification apparatus for total phosphorus.

FIG. 3 is a diagram showing a calibration curve created in Example 1. FIG. 6 is a diagram showing a calibration curve created in Example 2. FIG. 6 is a diagram showing a calibration curve created in Example 3. The figure which shows the calibration curve created in Example 4. FIG. FIG. 6 is a diagram showing a calibration curve created in Example 5. FIG. 6 is a diagram showing a calibration curve created in Example 6. FIG. 10 is a diagram showing a calibration curve created in Example 7. FIG. 10 is a diagram showing a calibration curve created in Example 8. FIG. 10 shows a calibration curve created in Example 9. FIG. 10 is a diagram showing a calibration curve created in Example 10. FIG. 10 is a diagram showing a calibration curve created in Example 11. The figure which shows the calibration curve created in Example 12. The figure which shows the calibration curve created in Example 13.

  The test water capable of quantifying total phosphorus by the method of the present invention is not particularly limited, but it is usually a wastewater that is regulated by phosphorus discharge such as factory wastewater and domestic wastewater, as well as marine water and lakes. Natural water such as water, river water and groundwater.

  When quantifying the total phosphorus of the test water, a predetermined amount of the test water is collected, and a pretreatment is performed to convert the phosphorus compound contained in the test water into phosphate ions. In this pretreatment, first, an alkali metal salt of peroxodisulfuric acid or ammonium peroxodisulfate (hereinafter sometimes referred to as a peroxodisulfuric acid compound) and sulfuric acid are added to test water, and boiling of the test water starts at 65 ° C. under normal pressure. It is heated for a predetermined time at a temperature up to the temperature, preferably from 75 ° C. to the boiling temperature of the inspection water (step 1). As a result, organic and inorganic phosphorus compounds, particularly organic phosphorus compounds, contained in the test water are oxidatively decomposed by the peroxodisulfuric acid compound, and phosphorus elements are converted into phosphate ions.

  The alkali metal salt of peroxodisulfuric acid used here is usually potassium peroxodisulfate or sodium peroxodisulfate.

  The peroxodisulfuric acid compound is usually added to test water as an aqueous solution dissolved in purified water, for example, pure water, distilled water or ion exchange water. The concentration of this aqueous solution is usually preferably set to 0.4 to 50 g / liter, and more preferably set to 3.0 to 40 g / liter. The amount of the peroxodisulfuric acid compound aqueous solution added to the test water is preferably set so that the concentration of the peroxodisulfate compound in the test water can sufficiently oxidatively decompose the phosphorus compound contained in the test water. If it is added, the peroxodisulfuric acid compound remains in the inspection water, and there is a possibility of causing false color development in Step 3 described later. For this reason, the concentration of the peroxodisulfuric acid compound in the test water is preferably set so that the concentration of the peroxodisulfuric acid compound aqueous solution and sulfuric acid added to the test water is usually 0.5 to 9 g / liter. 1 to 6 g / liter is more preferable.

  On the other hand, the amount of sulfuric acid added to the inspection water is preferably set so that the concentration of sulfuric acid when the aqueous peroxodisulfuric acid compound solution and sulfuric acid are added to the inspection water is 0.1 M or more. However, if too much is added, neutralization treatment of excess sulfuric acid may be necessary for the purpose of generating molybdenum blue (coloration of phosphate ions) in Step 2 and later described below. It is preferable to set to 0.1 to 0.3M.

  The heating time of the inspection water in this step varies depending on the heating temperature, but is usually preferably set to 20 to 40 minutes.

  Next, a first aqueous solution containing a predetermined saccharide is added to the test water that has undergone step 1, and subsequently heated for a predetermined time (step 2). This process can be applied to the test water in the high temperature state or the heating continuation state after completion of the process 1 without cooling the test water that has passed through the process 1 by standing cooling or the like.

  The first aqueous solution comprises a predetermined saccharide, that is, an aldose having 5 carbon atoms, an aldose having 6 carbon atoms, a ketose having 6 carbon atoms, and an oligosaccharide capable of producing an aldose having 6 carbon atoms or a ketose having 6 carbon atoms by decomposition. A saccharide selected from the group is dissolved in purified water. Examples of aldoses having 5 carbon atoms include ribose, arabinose and xylose. Examples of aldoses having 6 carbon atoms include altrose, glucose, mannose and galactose. Examples of ketoses having 6 carbon atoms include fructose and sorbose.

  Examples of the oligosaccharide capable of producing a aldose having 6 carbon atoms or a ketose having 6 carbon atoms by decomposition include, for example, disaccharides sucrose, maltose, lactose, isomaltulose, maltulose, lactulose, galactosucrose and primeverose, trisaccharide And raffinose, kestose, gentianose, planteose and umbelliferose, the tetrasaccharide stachyose and the pentasaccharide Verbasse. These exemplary oligosaccharides, upon decomposition, produce xylose (5 carbon aldose), glucose (6 carbon aldose), galactose (6 carbon aldose) or fructose (6 carbon ketose). Can do. The oligosaccharide may be capable of generating monosaccharides other than these together with aldose having 6 carbon atoms or ketose having 6 carbon atoms by decomposition.

  The concentration of saccharides in the first aqueous solution is usually preferably set to 30 to 600 g / liter. Further, the amount of the first aqueous solution added to the test water is such that the concentration of saccharide in the test water (the concentration of aldose having 6 carbons or ketose having 6 carbons produced by decomposition when oligosaccharide is used) remains in the test water. The amount is set to be sufficiently larger than the amount necessary for eliminating the peroxodisulfuric acid compound. This is because it is necessary to use the saccharide added to the test water in this step as a reducing agent for the heteropoly compound produced in step 3 described later. For this reason, the amount of the first aqueous solution added to the test water is usually preferably set so that the sugar concentration in the test water is 2 to 60 g / liter, more preferably 5 to 40 g / liter. preferable.

  The heating temperature of the inspection water in this step can be usually set in the same temperature range as the heating in the step 1, but it is usually preferable to set the heating temperature in the step 1 to be the same. Moreover, although the heating time of the test water in this process changes with heating temperature, it is preferable to set normally several seconds-30 minutes.

  In this step, peroxo remaining in the test water without being consumed for the oxidative decomposition of the phosphorus compound due to the aldose having 5 carbon atoms, the aldose having 6 carbon atoms or the ketose having 6 carbon atoms of the added first aqueous solution. The disulfate compound is decomposed and disappears. In addition, in the first aqueous solution, when an oligosaccharide capable of producing a aldose having 6 carbon atoms or a ketose having 6 carbon atoms by decomposition is used as a saccharide, the oligosaccharide can be produced by the oligosaccharide itself or by heating in this step. The remaining peroxodisulfuric acid compound is decomposed and disappeared by the aldose having 6 carbon atoms or the ketose having 6 carbon atoms generated by hydrolysis of the sugar.

  Steps 1 and 2 can be operated under normal pressure and can be safely performed because no harmful gas is generated. In addition, since it is not necessary to cool the inspection water by allowing it to cool when the process 1 is shifted from the process 1 to the process 2, the test water after the completion of the process 1 can be transferred to the process 2 smoothly and quickly. The series of steps 1 and 2 can be completed in a short time.

  Next, an oligosaccharide, a molybdenum compound and an antimony compound capable of producing a aldose having 6 carbon atoms or a ketose having 6 carbon atoms by decomposition are added as an aqueous solution to the test water having undergone step 2, and the test water is brought to 65 ° C. or higher. Maintain (step 3). This process can be applied to the test water in the high temperature state or the heating continuation state after the completion of the process 2 without cooling the test water that has passed through the process 2 by cooling.

  The oligosaccharides used in this step are the same as those available in step 2.

  The molybdenum compound used in this step is hexammonium heptamolybdate or an alkali metal salt, alkaline earth metal salt or heavy metal salt of molybdic acid. Of these, hexammonium heptamolybdate or alkali metal salts or alkaline earth metal salts of molybdic acid are preferably used. Examples of alkali metal salts of molybdate include sodium molybdate, potassium molybdate and lithium molybdate. Examples of alkaline earth metal salts of molybdate include calcium molybdate and magnesium molybdate. Examples of the heavy metal salt of molybdate include zinc molybdate and aluminum molybdate.

  The antimony compound used in this step is an antimony compound having an antimony valence of 3 or 5. Examples of the antimony compound having an antimony valence of 3 include potassium antimonyl tartrate, antimony trioxide (ie, antimony (III) oxide), and an antimony halide salt having a valence of 3. As the antimony halide salt having a valence of 3, it is preferable to use antimony trichloride (that is, antimony (III) chloride) which does not easily generate a harmful substance by hydrolysis. On the other hand, examples of the antimony compound having antimony having a valence of 5 include antimony pentoxide (that is, antimony oxide (V)) and a halide salt of antimony having a valence of 5. As the halide salt of antimony having a valence of 5, it is preferable to use antimony pentachloride (that is, antimony chloride (V)) that does not easily generate harmful substances by hydrolysis.

  In this step, the oligosaccharide, the molybdenum compound and the antimony compound are added to the inspection water in the form of an aqueous solution prepared using purified water. At this time, an oligosaccharide aqueous solution, a molybdenum compound aqueous solution and an antimony compound aqueous solution can be prepared, respectively, and each aqueous solution can be separately added to the test water. Moreover, the aqueous solution of oligosaccharide and the aqueous solution containing a molybdenum compound and an antimony compound simultaneously can be prepared separately, and these aqueous solutions can be added separately with respect to test water. Since the aqueous solutions used in these addition methods are all stable, they can be prepared and stored in advance and used as appropriate.

  However, the oligosaccharide, the molybdenum compound and the antimony compound are preferably added to the test water as an aqueous solution containing these simultaneously. This aqueous solution (hereinafter sometimes referred to as a second aqueous solution, which corresponds to the phosphate ion color former according to the present invention) includes, for example, an oligosaccharide aqueous solution, a molybdenum compound aqueous solution and an antimony compound aqueous solution, respectively. It can be prepared by mixing each aqueous solution immediately before adding it to the test water, and preparing an aqueous solution of oligosaccharide and an aqueous solution containing a molybdenum compound and an antimony compound separately. It can also be prepared by mixing immediately before the aqueous solution is added to the test water.

  When a non-reducing oligosaccharide capable of producing a aldose having 6 carbon atoms or a ketose having 6 carbon atoms by decomposition is used as the oligosaccharide, the oligosaccharide, molybdenum compound and antimony compound are simultaneously dissolved in purified water. Two aqueous solutions can also be prepared. This second aqueous solution can be stably stored for a long period of time because the reaction between the solutes does not proceed substantially. Non-reducing oligosaccharides that can be used in this form of the second aqueous solution are usually sucrose, raffinose, kestose or stachyose, and these oligosaccharides are decomposed by glucose (C6-Caldose), galactose ( 6 carbon aldoses) or fructose (6 carbon ketoses) can be produced.

  When an alkaline earth metal salt of molybdic acid is used as the molybdenum compound, an appropriate amount of sulfuric acid or hydrochloric acid is added to promote dissolution of the alkaline earth metal salt of molybdic acid in water during the preparation of the various aqueous solutions described above. Can be added. When antimony trioxide or antimony pentoxide is used as the antimony compound, an appropriate amount of hydrochloric acid may be added to promote dissolution of antimony trioxide or antimony pentoxide in water during the preparation of the various aqueous solutions described above. it can.

  In this step, the concentration of oligosaccharide in test water is 3 to 60 g / liter, the concentration of molybdenum compound in test water is 0.4 to 3.0 g / liter, and the concentration of antimony compound in test water is 0.01 to It is preferable to add the above-mentioned various aqueous solutions to the inspection water so that the amount is 0.24 g / liter. In particular, the concentration of the oligosaccharide in the test water is 6 to 50 g / liter, the concentration of the molybdenum compound in the test water is 0.6 to 2.0 g / liter, and the concentration of the antimony compound in the test water is 0.02 to 0.4. It is preferable to add the above-mentioned various aqueous solutions so as to be 15 g / liter.

  In this step, when the second aqueous solution prepared by simultaneously dissolving the non-reducing oligosaccharide, the molybdenum compound and the antimony compound in purified water is added to the test water, the non-reducing property in the second aqueous solution is added. The concentration of the oligosaccharide is usually preferably set to be 30 to 600 g / liter. Further, the concentration of the molybdenum compound in the second aqueous solution (concentration converted excluding water molecules when a hydrate is used) is usually preferably set to 1 to 30 g / liter, and preferably 2 to 25 g / liter. It is more preferable to set it to liters. Furthermore, it is preferable that the concentration of the antimony compound in the second aqueous solution (concentration converted excluding water molecules when a hydrate is used) is usually set to 0.04 to 1.2 g / liter, More preferably, the setting is 0.08 to 1.0 g / liter. However, in the second aqueous solution, the concentration ratio (A: B) between the antimony compound (A) and the molybdenum compound (B) is preferably set to be 1: 8 to 100, and is preferably 1:10 to 50. It is more preferable to set so.

  In the second aqueous solution, when the concentrations of the non-reducing oligosaccharide, the molybdenum compound and the antimony compound are set as described above, the ratio of the second aqueous solution in the test water after the addition of the second aqueous solution is 6 to 20% by volume. By setting the amount of the second aqueous solution to be added to the test water, the concentrations of the oligosaccharide, the molybdenum compound, and the antimony compound in the test water can be easily set to the above-described ranges.

  In this step, each aqueous solution described above can be added to the inspection water while continuing the heating in step 2. Thereby, the inspection water to which each aqueous solution is added is maintained at 65 ° C. or higher. The time for maintaining the inspection water at the same temperature or higher is usually set to 3 to 60 minutes. When the heating temperature of the inspection water in step 2 is set to a temperature sufficiently higher than 65 ° C., the heating is stopped at the time of transition from step 2 to step 3 or after the transition to step 3, and the inspection water In this step, the temperature of the inspection water can be maintained at 65 ° C. or higher for a predetermined time while naturally cooling.

  In this process, the phosphate ion originally contained in the test water and the phosphate ion generated by the oxidative decomposition of the phosphorus compound in the process 1 react with the molybdenum compound and the antimony compound added to the test water to form a heteropoly compound. Is generated. The produced heteropoly compound is produced by the aldose having 6 carbons or the ketose having 6 carbons produced by the decomposition of the oligosaccharide added in step 3 in an acidic environment with sulfuric acid added in step 1, and the oligosaccharide Is a reducing oligosaccharide, it is reduced by the oligosaccharide itself. In the test water, the aldose having 5 carbon atoms, the aldose having 6 carbon atoms or the ketose having 6 carbon atoms, the aldose having 6 carbon atoms produced by the decomposition of the oligosaccharide, or the 6 carbon atoms of the first aqueous solution added in step 2 is used. In the case where the ketose or the oligosaccharide is a reducing oligosaccharide, it is also reduced by the oligosaccharide remaining in step 2 without being consumed due to the decomposition of the peroxodisulfate compound. This reduction produces molybdenum blue (coloration of phosphate ions), and this molybdenum blue changes the color of the inspection water.

  Next, the absorbance at an arbitrary wavelength in the range of 600 to 950 nm is measured for the test water discolored by molybdenum blue (step 4). Then, based on a calibration curve prepared by examining the relationship between the absorbance and the phosphate ion concentration in advance, the phosphate ion amount of the test water, that is, the total phosphorus amount is determined from the absorbance measurement value.

  The method for quantifying total phosphorus according to the present invention can be safely carried out without using a special reaction apparatus such as a pressure vessel that requires attention in handling, and it is not necessary to cool inspection water between processes. Therefore, a series of processes can be smoothly advanced without interruption, and can be completed in a short time. Furthermore, the peroxodisulfuric acid compound aqueous solution and sulfuric acid used in Step 1, the first aqueous solution used in Step 2, and each aqueous solution used in Step 3 are both stable and can be stored. For this reason, this quantification method is easy to apply to automation, that is, an automated apparatus. In particular, in Step 3, when a second aqueous solution containing a non-reducing oligosaccharide, a molybdenum compound and an antimony compound is used at the same time, the second aqueous solution can be prepared and stored in advance. It is easier to apply to the device.

  In the method for determining total phosphorus according to the present invention, when a calibration curve is prepared, the linear relationship between the phosphate ion concentration and the absorbance at an arbitrary wavelength in the range of 600 to 950 nm is relatively high. Since it is well established to the range of the phosphate ion concentration, the upper limit of quantification of phosphate ions contained in the test water is expanded to a range of 4 mg [P] / liter or more. Therefore, this quantification method can also be applied to test water having a high content of phosphate ions and phosphorus compounds.

  In the quantification method of the present invention, when the second aqueous solution used in step 3 contains non-reducing oligosaccharides, molybdenum compounds and antimony compounds at the same time, the same as the second aqueous solution used in step 3 as the first aqueous solution used in step 2 Things can be used. In this case, in the step 2, the second aqueous solution is added while continuing the heating in the step 1, and the aldose having 6 carbons or the ketose having 6 carbons generated by the decomposition of the oligosaccharide contained therein, or the The peroxodisulfuric acid compound contained in the test water is extinguished by the oligosaccharide itself.

  In Step 2, when the second aqueous solution is used as the first aqueous solution, the amount used is usually set to about 5 to 100% by volume, preferably about 10 to 50% by volume of the second aqueous solution used in Step 3.

  In step 2, when the second aqueous solution is used as the first aqueous solution as described above, it is not necessary to prepare the first aqueous solution separately. Therefore, when the quantitative method of the present invention is automated, the automation device is simplified. be able to.

The unit of mg [P] / liter indicates the number of milligrams of phosphorus contained in one liter of water.
Reagents and spectrophotometers The reagents and spectrophotometers used in the following examples and the like are as follows.
Phosphorus standard solution (for water quality test): Wako Pure Chemical Industries, Ltd. Code 160-19241
1M sulfuric acid (for volumetric analysis): Wako Pure Chemical Industries, Ltd. Code 198-09595
Hydrochloric acid (special grade reagent): Wako Pure Chemical Industries, Ltd. Code 080-01066
Sulfuric acid (special grade reagent): Wako Pure Chemical Industries, Ltd. Code 192-04696
Potassium peroxodisulfate (for nitrogen and phosphorus measurement): Wako Pure Chemical Industries, Ltd. Code 169-1189
Ammonium peroxodisulfate (special grade reagent): Wako Pure Chemical Industries, Ltd. Code 012-03285
Hexammonium hexamolybdate tetrahydrate (special reagent grade): Wako Pure Chemical Industries, Ltd. Code 018-06901
Lithium molybdate: Wako first grade code 125-03501 from Wako Pure Chemical Industries, Ltd.
Potassium molybdate: Wako Pure Chemical Industries, Ltd. Code 165-04002
Molybdenum (VI) disodium dihydrate (reagent special grade): Wako Pure Chemical Industries, Ltd. Code 190-02475
Calcium molybdate: Wako Pure Chemical Industries, Ltd. Code 034-00682
Potassium antimony tartrate trihydrate (special grade reagent): Wako Pure Chemical Industries, Ltd. Code 020-12832
Antimony oxide (III) (chemical use): Wako Pure Chemical Industries, Ltd. Code 018-04402
Antimony (III) chloride (reagent special grade): Wako Pure Chemical Industries, Ltd. Code 011-0492
D-fructose: Wako special grade code 127-02765 of Wako Pure Chemical Industries, Ltd.
D-arabinose: Wako Special Code 013-04572 from Wako Pure Chemical Industries, Ltd.
D-glucose (special reagent grade): Wako Pure Chemical Industries, Ltd. Code 047-100592
Sucrose (special grade reagent): Wako Pure Chemical Industries, Ltd. Code 196-00001
D-Raffinose pentahydrate (reagent special grade): Wako Pure Chemical Industries, Ltd. Code 180-00012
D-maltose monohydrate: Wako special grade code 130-00615 from Wako Pure Chemical Industries, Ltd.
Lactose monohydrate (special grade): Wako Pure Chemical Industries, Ltd. Code 128-00095
D-galactose (reagent special grade): Wako Pure Chemical Industries, Ltd. Code 071-00032
1-kestose (for biochemistry): Wako Pure Chemical Industries, Ltd. Code 112-00433
Stachyose n hydrate: Wako Pure Chemical Industries, Ltd. Code 196-12864
Isomaltulose: Palatinose monohydrate (for biochemistry) from Wako Pure Chemical Industries, Ltd. Code 169-12991
Martulose monohydrate: Tokyo Chemical Industry Co., Ltd. Code M1138
Lactulose (for biochemistry): Wako Pure Chemical Industries, Ltd. Code 126-03732
Adenosine-5′-triphosphate disodium salt trihydrate (for biochemistry): Wako Pure Chemical Industries, Ltd. Code 018-16911
Phenyl disodium phosphate dihydrate: Wako Special Grade Code 044-04262 from Wako Pure Chemical Industries, Ltd.
Sodium diphosphate decahydrate (special grade reagent): Wako Pure Chemical Industries, Ltd. Code 195-03025
L-ascorbic acid (special reagent grade): Wako Pure Chemical Industries, Ltd. Code 014-04801
Spectrophotometer: Shimadzu Corporation trade name “UV-1600PC”

Phosphate ion solution The phosphate ion solution used in the following examples and the like is as follows.
Five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0, and 4.0 mg [P] / liter were prepared. For phosphate ion solutions with a phosphate ion concentration of 0 mg [P] / liter, distilled water was used as it was, and for other phosphate ion solutions, the phosphate standard concentration was adjusted by diluting the phosphorus standard solution with distilled water. .

Experimental example 1
The following sample water and oxidizer aqueous solution were prepared. D-glucose used for the preparation of the sample waters 2, 3 and 4 assumes an organic substance as a contaminant.
<Sample water>
Sample water 1:
A phosphate ion solution having a phosphate ion concentration adjusted to 5 mg [P] / liter by diluting a phosphorus standard solution with distilled water.
Sample water 2:
An aqueous solution obtained by dissolving sodium diphosphate decahydrate and D-glucose in distilled water (concentration in terms of sodium diphosphate is 5 mg [P] / liter, D-glucose concentration is 40 mg / liter).
Sample water 3:
An aqueous solution obtained by dissolving adenosine-5′-triphosphate disodium trihydrate and D-glucose in distilled water (adenosine-5′-triphosphate disodium equivalent concentration is 5 mg [P] / liter) D-glucose concentration is 40 mg / liter).
Sample water 4:
Aqueous solution obtained by dissolving phenyl disodium phosphate dihydrate and D-glucose in distilled water (phenyl disodium phosphate equivalent concentration is 5 mg [P] / liter, D-glucose concentration is 40 mg / liter) .

<Oxidizing agent aqueous solution>
Oxidizing agent aqueous solution 1:
An aqueous potassium peroxodisulfate solution having a concentration of 40 g / liter (an aqueous potassium peroxodisulfate solution having a concentration described in 46.1.1.1 of JIS K 0102 (hereinafter referred to as “JIS method concentration”)).
Oxidizing agent aqueous solution 2:
A potassium peroxodisulfate aqueous solution having a concentration of 20 g / liter (a potassium peroxodisulfate aqueous solution having a concentration of 50% of the JIS method concentration).
Oxidizing agent aqueous solution 3:
A potassium peroxodisulfate aqueous solution having a concentration of 8 g / liter (a potassium peroxodisulfate aqueous solution having a concentration of 20% of the JIS method concentration).
Oxidizing agent aqueous solution 4:
A potassium peroxodisulfate aqueous solution having a concentration of 4 g / liter (a potassium peroxodisulfate aqueous solution having a concentration of 10% of the JIS method concentration).
Oxidizing agent aqueous solution 5:
A potassium peroxodisulfate aqueous solution having a concentration of 2 g / liter (a potassium peroxodisulfate aqueous solution having a concentration of 5% of the JIS method concentration).
Oxidizing agent aqueous solution 6:
A potassium peroxodisulfate aqueous solution having a concentration of 0.4 g / liter (a potassium peroxodisulfate aqueous solution having a concentration of 1% of the JIS method concentration).

  One milliliter of one of the oxidizer aqueous solutions 1 to 6 is added to 5 ml of each of the sample waters 1 to 4, and 1 ml of 1M sulfuric acid is further added, and then each sample water is added at 95 ° C. using a block heater. Heated for minutes. Each sample water was diluted 5 times with distilled water, and each sample water was colored according to the molybdenum blue (ascorbic acid reduction) spectrophotometric method described in 46.1.1 of JIS K 0102, and the absorbance at 890 nm was obtained. It was measured. That is, 0.2 ml of a 5: 1 mixed solution of ammonium molybdate solution and ascorbic acid solution specified in the same method was added to diluted sample water, left at 25 ° C. for about 15 minutes, and then absorbed at 890 nm. Was measured. The results are shown in Table 1.

  In Table 1, the oxidative degradation rate of sample waters 2 to 4 is the ratio of absorbance to the absorbance measured for sample water 1, and is converted into phosphate ions by oxidative degradation among the phosphorous compounds contained in sample water. Shows the percentage of food. According to the oxidative degradation rate in Table 1, the phosphorus compound contained in the sample water was 90% or more when an aqueous solution (oxidant aqueous solution 4) having a potassium peroxodisulfate concentration of 4 g / liter or more was used. When an aqueous solution (oxidant aqueous solution 3) having a concentration of 8 g / liter or more is used, 95% or more is decomposed and converted into phosphate ions. From this, potassium peroxodisulfate in the oxidizing agent aqueous solution can effectively oxidatively decompose the phosphorus compound contained in the sample water even when the concentration is set to about 1/5 or less of the JIS method concentration. .

Experimental example 2
The following sample water was prepared. D-glucose used for the preparation of the sample waters 5 and 6 is assumed to be an organic substance as a contaminant.
Sample water 5:
Dissolving adenosine-5'-triphosphate disodium trihydrate, phenyl disodium phosphate dihydrate and D-glucose in distilled water to a concentration of 1 mg adenosine-5'-triphosphate. [P] / liter, an aqueous solution in which phenyl disodium phosphate concentration is adjusted to 1 mg [P] / liter, and D-glucose concentration is adjusted to 50 mg / liter.
Sample water 6:
An aqueous solution in which sodium diphosphate decahydrate and D-glucose are dissolved in distilled water to adjust the sodium diphosphate concentration to 2 mg [P] / liter and the D-glucose concentration to 50 mg / liter.

  To 5 ml of each sample water, 0.8 ml of an aqueous potassium peroxodisulfate solution having a concentration of 30 g / liter and 1.2 ml of 1M sulfuric acid were added. And each sample water was heated for 40 minutes at 95 degreeC using the block heater, Then, it cooled with water rapidly. Distilled water was added to each sample water after cooling to dilute it twice, and in the same manner as in Experimental Example 1, according to molybdenum blue (ascorbic acid reduction) spectrophotometric method described in 46.1.1 of JIS K 0102 Each sample water was colored and the absorbance at 890 nm was measured. Moreover, about the case where the heating time of each sample water by a block heater was shortened, the sample water was similarly developed and the light absorbency of 890 nm was measured. The results are shown in Table 2.

  In Table 2, the relative decomposition rate means the decomposition rate of the phosphorus compound at each heating time when the decomposition rate of the phosphorus compound contained in each sample water is 100% when the heating time is 40 minutes, This is calculated based on the ratio of the absorbance to the absorbance when the heating time is 40 minutes. According to Table 2, it can be seen that the phosphorus compound in the sample water is decomposed by 90% or more in 25 minutes and 98% or more in 30 minutes.

Example 1
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, while maintaining the state heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Subsequently, while maintaining the state heated to 95 ° C., 0.4 ml of color former was further added and left for 7 minutes. The color former used here is a solution in which sucrose, hexaammonium heptamolybdate tetrahydrate and potassium antimonyl tartrate trihydrate are dissolved in distilled water, and the concentration of sucrose is 100 g / liter, hexamolybdate hexahydrate. The concentration of ammonium tetrahydrate was adjusted to 8 g / liter, and the concentration of potassium antimonyl tartrate trihydrate was adjusted to 0.32 g / liter.

  About each phosphate ion solution processed above, the absorbance at 840 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 1, this calibration curve shows high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Adenosine-5′-triphosphate disodium trihydrate concentration of 65 mg / liter (1 mg [P] / liter), phenyl disodium phosphate dihydrate concentration of 82 mg / liter (1 mg [P] / liter) , D-glucose (assuming organic substances as impurities) in distilled water to a concentration of 50 mg / liter adenosine-5′-triphosphate disodium trihydrate, phenyl disodium phosphate dihydrate And D-glucose were dissolved to prepare test water. This test water has a total phosphorus concentration of 2 mg [P] / liter.

  0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 30 g / liter were added to the test water and heated at 95 ° C. for 40 minutes using a block heater. Next, with the test water heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Further, 0.4 ml of the color former was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes. The color former used in these steps is the same as that used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 840 nm was measured and the total phosphorus density | concentration of test water was determined based on the analytical curve created from the measured value, it was 1.95 mg [P] / liter.

Example 2
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, while maintaining the state heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Subsequently, while maintaining the state heated to 95 ° C., 0.4 ml of color former was further added and left for 7 minutes. The color former used here was prepared by dissolving D-raffinose pentahydrate, hexaammonium heptamolybdate tetrahydrate and potassium antimonyl tartrate trihydrate in distilled water, and D-raffinose pentahydrate. The concentration of the product was adjusted to 100 g / liter, the concentration of hexaammonium heptamolybdate tetrahydrate to 8 g / liter, and the concentration of antimonyl potassium tartrate trihydrate to 0.32 g / liter.

  About each phosphate ion solution processed above, the absorbance at 840 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 2, this calibration curve shows a high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 30 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, with the test water heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Further, 0.4 ml of the color former was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes. The color former used in these steps is the same as that used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 840 nm was measured and the total phosphorus density | concentration of test water was determined based on the analytical curve created from the measured value, it was 1.96 mg [P] / liter.

Example 3
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, while maintaining the state heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Subsequently, while maintaining the state heated to 95 ° C., 0.4 ml of color former was further added and left for 7 minutes. The color former used here was prepared by dissolving 1-kestose, disodium molybdenum (VI) acid dihydrate and antimony (III) chloride in distilled water, and the concentration of 1-kestose was 80 g / liter, molybdenum. (VI) The concentration of disodium acid dihydrate was adjusted to 15 g / liter, and the concentration of antimony (III) chloride was adjusted to 0.25 g / liter.

  For each phosphate ion solution treated as described above, the absorbance at 700 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 3, this calibration curve shows high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, and 0.6 ml of 1M sulfuric acid and 0.4 ml of ammonium peroxodisulfate having a concentration of 30 g / liter were added to the test water, and a block heater was used. Heated at 95 ° C. for 40 minutes. Next, with the test water heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Further, 0.4 ml of the color former was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes. The color former used in these steps is the same as that used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 700 nm was measured and the total phosphorus density | concentration of test water was determined based on the analytical curve created from the measured value, it was 1.98 mg [P] / liter.

Example 4
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, while maintaining the state heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Subsequently, while maintaining the state heated to 95 ° C., 0.4 ml of color former was further added and left for 7 minutes. The color former used here is a solution in which stachyose n-hydrate, calcium molybdate aqueous solution and antimony (III) oxide aqueous solution are dissolved in distilled water, and the concentration of stachyose n-hydrate is 200 g / liter, calcium molybdate. And the concentration of antimony (III) oxide were adjusted to 0.4 g / liter, respectively. The calcium molybdate aqueous solution used in the preparation of the color former is obtained by dissolving calcium molybdate with a small amount of hydrochloric acid in distilled water. The antimony (III) oxide aqueous solution is obtained by dissolving antimony (III) oxide in distilled water using a small amount of hydrochloric acid.

  About each phosphate ion solution processed above, the absorbance at 870 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 4, this calibration curve shows high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, and 0.6 ml of 1M sulfuric acid and 0.4 ml of ammonium peroxodisulfate having a concentration of 30 g / liter were added to the test water, and a block heater was used. Heated at 95 ° C. for 40 minutes. Next, with the test water heated to 95 ° C., 0.1 ml of a color former was added and left for 3 minutes. Further, 0.4 ml of the color former was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes. The color former used in these steps is the same as that used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 870 nm was measured and the total phosphorus density | concentration of the test water was determined based on the analytical curve created from the measured value, it was 1.93 mg [P] / liter.

Example 5
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 35 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves D-arabinose in distilled water so that a density | concentration may be 300 g / liter. The second aqueous solution is obtained by dissolving sucrose, potassium molybdate and antimonyl potassium tartrate trihydrate in distilled water. The concentration of sucrose is 100 g / liter, the concentration of potassium molybdate is 15 g / liter, and tartaric acid. The concentration of antimonyl potassium trihydrate was adjusted to 0.32 g / liter.

  For each phosphate ion solution treated as described above, the absorbance at 600 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 5, this calibration curve shows high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of ammonium peroxodisulfate having a concentration of 35 g / liter were added to the test water, and a block heater was used. Heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  The absorbance at 600 nm was measured for the test water after completion of heating, and the total phosphorus concentration of the test water was determined based on a calibration curve created from the measured value, and it was 1.97 mg [P] / liter.

Example 6
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 35 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves D-glucose in distilled water so that a density | concentration may be 400 g / liter. The second aqueous solution is prepared by dissolving D-raffinose pentahydrate, lithium molybdate and antimonyl potassium tartrate trihydrate in distilled water, and the concentration of D-raffinose pentahydrate is 100 g / liter. The concentration of lithium molybdate was adjusted to 8 g / liter, and the concentration of potassium antimonyl tartrate trihydrate was adjusted to 0.32 g / liter.

  For each phosphate ion solution treated as described above, the absorbance at 700 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 6, this calibration curve shows a high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of ammonium peroxodisulfate having a concentration of 35 g / liter were added to the test water, and a block heater was used. Heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 700 nm was measured and the total phosphorus density | concentration of test water was determined based on the analytical curve created from the measured value, it was 1.93 mg [P] / liter.

Example 7
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of potassium peroxodisulfate having a concentration of 35 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves D-fructose in distilled water so that a density | concentration may be 400 g / liter. The second aqueous solution is obtained by dissolving 1-kestose, disodium molybdate (VI) dihydrate and potassium antimonyl tartrate trihydrate in distilled water, and the concentration of 1-kestose is 80 g / liter. The concentration of disodium molybdate (VI) dihydrate was adjusted to 15 g / liter, and the concentration of potassium antimonyl tartrate trihydrate was adjusted to 0.32 g / liter.

  For each phosphate ion solution treated as described above, the absorbance at 800 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 7, this calibration curve shows a high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 35 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 800 nm was measured and the total phosphorus density | concentration of the test water was determined based on the analytical curve created from the measured value, it was 2.01 mg [P] / liter.

Example 8
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 35 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves D-galactose in distilled water so that a density | concentration may be 200 g / liter. The second aqueous solution is prepared by dissolving sucrose, lithium molybdate and antimony (III) chloride in distilled water. The concentration of sucrose is 100 g / liter, the concentration of lithium molybdate is 8 g / liter, and antimony chloride (III ) Is adjusted to 0.25 g / liter.

  For each phosphate ion solution treated as described above, the absorbance at 900 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 8, this calibration curve shows high linearity at least in the range of the phosphate ion concentration of 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 35 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  The absorbance of 900 nm was measured for the test water after completion of heating, and the total phosphorus concentration of the test water was determined based on a calibration curve created from the measured value, and it was 1.95 mg [P] / liter.

Example 9
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of potassium peroxodisulfate having a concentration of 8 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves D-maltose in distilled water so that a density | concentration may be 300 g / liter. The second aqueous solution is obtained by dissolving stachyose n hydrate, potassium molybdate and antimony (III) chloride in distilled water. The concentration of stachyose n hydrate is 200 g / liter, and the concentration of potassium molybdate is 15 g / liter, and the concentration of antimony (III) chloride was adjusted to 0.25 g / liter.

  For each phosphate ion solution treated as described above, the absorbance at 700 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 8, this calibration curve shows high linearity at least in the range of the phosphate ion concentration of 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 8 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 700 nm was measured and the total phosphorus density | concentration of test water was determined based on the analytical curve created from the measured value, it was 1.90 mg [P] / liter.

Example 10
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of potassium peroxodisulfate having a concentration of 8 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The first aqueous solution used here is one in which lactose monohydrate is dissolved in distilled water so as to have a concentration of 200 g / liter. The second aqueous solution is prepared by dissolving sucrose, disodium molybdenum (VI) dihydrate and an aqueous solution of antimony (III) oxide in distilled water. The concentration of sucrose is 100 g / liter, and molybdenum (VI) acid. The concentration of disodium dihydrate was adjusted to 15 g / liter, and the concentration of antimony (III) oxide was adjusted to 0.4 g / liter. The antimony (III) oxide aqueous solution used in the preparation of the second aqueous solution is obtained by dissolving antimony (III) oxide in distilled water using a small amount of hydrochloric acid.

  About each phosphate ion solution processed above, the absorbance at 750 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 10, this calibration curve shows high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 8 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 750 nm was measured and the total phosphorus density | concentration of the test water was determined based on the analytical curve created from the measured value, it was 1.92 mg [P] / liter.

Example 11
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of potassium peroxodisulfate having a concentration of 20 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves isomaltulose in distilled water so that a density | concentration may be 300 g / liter. The second aqueous solution is prepared by dissolving D-raffinose pentahydrate, calcium molybdate aqueous solution and antimony (III) chloride in distilled water. The concentration of D-raffinose pentahydrate is 100 g / liter, molybdenum. The concentration of calcium acid was adjusted to 12 g / liter, and the concentration of antimony (III) chloride was adjusted to 0.25 g / liter. The calcium molybdate aqueous solution used in the preparation of the second aqueous solution is obtained by dissolving calcium molybdate with a small amount of sulfuric acid in distilled water.

  For each phosphate ion solution treated as described above, the absorbance at 800 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 11, this calibration curve shows high linearity at least in the range of the phosphate ion concentration of 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 20 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 800 nm was measured and the total phosphorus density | concentration of test water was determined based on the analytical curve created from the measured value, it was 1.96 mg [P] / liter.

Example 12
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 20 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves maltulose in distilled water so that a density | concentration may be 300 g / liter. The second aqueous solution is obtained by dissolving 1-kestose, hexaammonium heptamolybdate tetrahydrate and an antimony (III) oxide aqueous solution in distilled water. The concentration of 1-kestose is 80 g / liter, hepamolybdic acid. The concentration of hexaammonium tetrahydrate was adjusted to 8 g / liter, and the concentration of antimony (III) oxide was adjusted to 0.4 g / liter. The antimony (III) oxide aqueous solution used in the preparation of the second aqueous solution is obtained by dissolving antimony (III) oxide in distilled water using a small amount of hydrochloric acid.

  About each phosphate ion solution processed above, the absorbance at 850 nm was measured, and a calibration curve for judging the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 12, this calibration curve shows high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of ammonium peroxodisulfate having a concentration of 20 g / liter were added to the test water, and a block heater was used. Heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 850 nm was measured and the total phosphorus density | concentration of the test water was determined based on the analytical curve created from the measured value, it was 1.97 mg [P] / liter.

Example 13
(Create a calibration curve)
0.6 ml of 1M sulfuric acid for 2.5 ml of each of the five types of phosphate ion solutions having phosphate ion concentrations of 0, 1.0, 2.0, 3.0 and 4.0 mg [P] / liter And 0.4 ml of ammonium peroxodisulfate having a concentration of 8 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater.

  Next, the state heated to 95 ° C. was maintained, and 0.1 ml of the first aqueous solution was added and left for 3 minutes. Subsequently, 0.4 ml of the second aqueous solution was further added while maintaining the state heated to 95 ° C., and left for 7 minutes. The 1st aqueous solution used here melt | dissolves lactulose in distilled water so that a density | concentration may be 300 g / liter. The second aqueous solution is obtained by dissolving stachyose n-hydrate, hexaammonium heptamolybdate tetrahydrate and antimonyl potassium tartrate trihydrate in distilled water, and the concentration of stachyose n-hydrate is 200 g. / Liter, the concentration of hexaammonium heptamolybdate tetrahydrate was adjusted to 8 g / liter, and the concentration of potassium antimonyl tartrate trihydrate was adjusted to 0.32 g / liter.

  About each phosphate ion solution processed above, the absorbance at 880 nm was measured, and a calibration curve for determining the phosphate ion concentration from the absorbance was prepared. The results are shown in FIG. According to FIG. 13, this calibration curve shows a high linearity at least in the range where the phosphate ion concentration is 0 to 4 mg [P] / liter.

(Total phosphorus determination of test water)
Test water similar to that used in Example 1 was prepared, 0.6 ml of 1M sulfuric acid and 0.4 ml of potassium peroxodisulfate having a concentration of 8 g / liter were added to the test water, and a block heater was used. And heated at 95 ° C. for 40 minutes. Next, 0.1 ml of the first aqueous solution was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.4 ml of the second aqueous solution was added while the test water was heated to 95 ° C., and the heating at the same temperature was continued for 7 minutes. The first aqueous solution and the second aqueous solution used in these steps are the same as those used when preparing the calibration curve.

  About the test water after completion | finish of a heating, when the light absorbency of 880 nm was measured and the total phosphorus density | concentration of the test water was determined based on the analytical curve created from the measured value, it was 1.91 mg [P] / liter.

Claims (9)

A method for quantifying total phosphorus in test water,
Adding an alkali metal salt of peroxodisulfuric acid or ammonium peroxodisulfate and sulfuric acid to the test water, and heating at a temperature from 65 ° C. to the boiling temperature of the test water for a predetermined time;
Selected from the group consisting of aldoses having 5 carbon atoms, aldoses having 6 carbon atoms, ketoses having 6 carbon atoms and oligosaccharides capable of producing aldoses having 6 carbon atoms or ketoses having 6 carbon atoms by decomposition in the test water having undergone step 1 Adding a first aqueous solution containing the prepared saccharide and subsequently heating for a predetermined time; and
Oligosaccharide, hexammonium heptamolybdate or alkali metal or alkaline earth metal salt of molybdic acid, and antimony that can generate aldose or carbon number 6 ketose by decomposition with respect to the test water passed through step 2 Adding an antimony compound having a valence of 3 or 5 as an aqueous solution and maintaining it at 65 ° C. or higher;
Step 4 for measuring the absorbance of any wavelength in the range of 600 to 950 nm for the test water that has undergone Step 3;
For the determination of total phosphorus, including   The method for quantifying total phosphorus according to claim 1, wherein the oligosaccharide is sucrose, maltose, lactose, raffinose, kestose, stachyose, isomaltulose or lactulose.   In step 3, the oligosaccharide, hexammonium heptamolybdate or alkali metal salt or alkaline earth metal salt of molybdic acid and the antimony compound having an antimony valence of 3 or 5 are used as a second aqueous solution containing these simultaneously. The method for quantifying total phosphorus according to claim 1, which is added to test water.   The method for quantifying total phosphorus according to claim 3, wherein the oligosaccharide contained in the second aqueous solution is a non-reducing oligosaccharide.   The method for quantifying total phosphorus according to claim 4, wherein the non-reducing oligosaccharide is sucrose, raffinose, kestose or stachyose.   The method for quantifying total phosphorus according to claim 4 or 5, wherein the second aqueous solution is used as the first aqueous solution. A color former for coloring phosphate ions contained in test water, which is used for quantifying total phosphorus in test water by the method for determining total phosphorus according to any one of claims 1 to 6 ,
Oligosaccharide capable of producing aldose or ketose having 6 carbon atoms by decomposition, hexammonium heptamolybdate or alkali metal salt or alkaline earth metal salt of molybdate, and antimony having antimony valence of 3 or 5 Consisting of an aqueous solution containing the compound,
Phosphate ion coloring agent.   8. The phosphate ion color former according to claim 7, wherein the oligosaccharide is a non-reducing oligosaccharide.   The phosphate ion coloring agent according to claim 8, wherein the non-reducing oligosaccharide is sucrose, raffinose, kestose or stachyose.

Images