JP2011237334A - Quatitative determination method of total phosphorus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively determine a total phosphorus in a test water in a short time.SOLUTION: A method of quantitatively determine the total phosphorus by converting a phosphorus compound in the test water into phosphate ions to quantitatively determine the phosphate ions in the test water comprises: a step 1 of adding an alkali peroxo-disulfate or ammonium peroxo-disulfate and sulfuric acid into the test water and heating them to 65°C to a boiling temperature; a step 2 of adding an aldose having 5 carbon atoms, an aldose having 6 carbon atoms, a ketose having 6 carbon atoms, or an aqueous solution of an oligosaccharide generating these aldoses or a ketose by decomposition into the test water through the step 1 and subsequently heating them; a step 3 of adding an aqueous solution containing hexaammonium heptamolybdate or an alkali metal molybdate or an alkali earth metal molybdate and an antimony compound in which a valence of antimony is 3 into the test water through the step 2 and maintaining the temperature at 65°C or higher; and a step 4 of determining an absorbance of the test water through the step 3 at an arbitrary wavelength in a range of 600-950 nm.

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.

  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 oxidative action of potassium peroxodisulfate, or sodium sulfite as a reducing agent is added to the test water in an alkaline state. It is necessary to extinguish potassium disulfate.

  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, as described in Non-Patent Document 1, the method for determining 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 relates to a method for quantifying the total phosphorus of test water by decomposing a phosphorus compound contained in test water and converting it into phosphate ions, and then quantifying the phosphate ions of the test water. In the method, an alkali metal salt of peroxodisulfuric acid or ammonium peroxodisulfate and sulfuric acid are added to test water, and the test water is heated for a predetermined time at a temperature from 65 ° C. to the boiling temperature of the test water; 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 5 carbon atoms, aldoses having 6 carbon atoms or 6 ketoses by decomposition. The first aqueous solution containing saccharides is added, followed by heating for a predetermined time, and in the test water that has passed through the step 2, hexamolybdate hexamolybdate or molybdic acid is added. Step 3 of adding a second aqueous solution containing an antimony compound having a valency of alkali metal salt or alkaline earth metal salt and antimony of 3 and maintaining the temperature at 65 ° C. or higher, and about 600 to 950 nm for the inspection water after Step 3 And step 4 of measuring the absorbance of an arbitrary wavelength in the range.

  Further, the present invention according to another aspect relates to a pretreatment method for test water for quantifying total phosphorus contained in test water, and the pretreatment method is an alkali metal of peroxodisulfuric acid to test water. Step 1 in which salt or ammonium peroxodisulfate and sulfuric acid are added and heated at a temperature from 65 ° C. to the boiling temperature of the test water for a predetermined time, and the aldose having 5 carbons and 6 carbons in the test water that has passed through Step 1 Adding a first aqueous solution containing a saccharide selected from the group consisting of aldoses having 5 carbon atoms, aldoses having 5 carbon atoms, aldoses having 6 carbon atoms or oligosaccharides capable of producing ketoses having 6 carbon atoms by decomposition. And a step 2 of heating for a predetermined time.

  The oligosaccharide used in the quantification method and pretreatment method of the present invention is usually sucrose, maltose, lactose, raffinose, kestose, stachyose, isomaltulose, maltulose or lactulose.

  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.

  In addition, since the pretreatment method for test water for the determination of total phosphorus according to the present invention includes steps 1 and 2 described above, the phosphorus compound contained in the test water can be safely converted into phosphate ions. Moreover, the test water after the treatment can be promptly applied to the phosphate ion determination step.

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 generates a predetermined saccharide, ie, a aldose having 5 carbon atoms, an aldose having 6 carbon atoms, a ketose having 6 carbon atoms, and an aldose having 5 carbon atoms, an aldose having 6 carbon atoms, or a ketose having 6 carbon atoms by decomposition. A saccharide selected from the group consisting of possible oligosaccharides 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 oligosaccharides that can generate aldoses having 5 carbon atoms, aldoses having 6 carbon atoms or ketoses having 6 carbon atoms by decomposition include, for example, disaccharides sucrose, maltose, lactose, isomaltulose, maltulose, lactulose, galacto Mention may be made of sucrose and primeverose, the trisaccharides 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 concentration of saccharides in the first aqueous solution is usually preferably set to 30 to 600 g / liter. The amount of the first aqueous solution added to the test water is the concentration of saccharide in the test water (if oligosaccharide is used, the concentration of aldose having 5 carbon atoms, aldose having 6 carbon atoms, or ketose having 6 carbon atoms produced by decomposition). ) Is sufficiently larger than the amount necessary to eliminate the peroxodisulfate compound remaining in the test water. 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 generating a aldose having 5 carbon atoms, an aldose having 6 carbon atoms, or a ketose having 6 carbon atoms by decomposition as a saccharide is used, the oligosaccharide itself or in this step The remaining peroxodisulfuric acid compound is decomposed and disappeared by the aldose having 5 carbon atoms, the aldose having 6 carbon atoms or the ketose having 6 carbon atoms produced by hydrolysis of the oligosaccharide by heating at.

  The pretreatment of the inspection water including the above 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. It can be completed in a short time.

  Next, a second aqueous solution containing a molybdenum compound and an antine compound is added to the inspection water that has been pretreated, that is, the inspection water that has undergone step 2, and maintained at 65 ° C. or higher (step 3).

  The molybdenum compound used here is hexaammonium 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 here is an antimony compound having an antimony valence of 3. Examples of the antimony compound having an antimony valence of 3 include potassium antimonyl tartrate, antimony trioxide (that is, antimony (III) oxide), and a halide salt of antimony. As the antimony halide salt, it is preferable to use antimony trichloride which hardly generates harmful substances by hydrolysis.

  The second aqueous solution can be prepared by dissolving a molybdenum compound and an antimony compound in purified water. Here, when an alkaline earth metal salt of molybdic acid is used as the molybdenum compound, an appropriate amount of sulfuric acid or hydrochloric acid can be added to promote dissolution of the alkaline earth metal salt of molybdic acid. When antimony trioxide is used as the antimony compound, an appropriate amount of hydrochloric acid can be added in order to promote dissolution of antimony trioxide.

  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 is preferably 2 to 25 g / liter. It is more preferable to set so. On the other hand, the concentration of the antimony compound in the second aqueous solution (in the case of using a hydrate, the concentration converted excluding water molecules) is usually preferably set to be 0.04 to 1.2 g / liter. It is more preferable that 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.

  The amount of the second aqueous solution added to the inspection water is usually such that the concentration of the molybdenum compound in the inspection water is 0.3 to 3.0 g / liter and the concentration of the antimony compound is 0.01 to 0.24 g / liter. It is preferable to set so that In particular, it is preferable to set the concentration of the molybdenum compound in the test water to 0.5 to 2.0 g / liter and the concentration of the antimony compound to 0.02 to 0.13 g / liter.

  In this step, the second aqueous solution can be added to the inspection water while continuing the heating in step 2. Thereby, the inspection water to which the second 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 Step 1 react with the molybdenum compound and antimony compound in the second aqueous solution to form a heteropoly compound. To do. Then, the produced heteropoly compound is an aldose having 5 carbon atoms, an aldose having 6 carbon atoms, an aldose having 6 carbon atoms or an oligosaccharide of the first aqueous solution added in step 2 in an acidic environment with sulfuric acid added in step 1. It is reduced by aldoses having 5 carbon atoms, aldoses having 6 carbon atoms, or ketoses having 6 carbon atoms produced by the decomposition, which remain without being consumed for the decomposition of the peroxodisulfuric acid compound. In the case where the oligosaccharide of the first aqueous solution is reducing, for example, maltose, lactose, isomaltulose, maltulose, lactulose and primeverose, the heteropoly compound produced by the reducing oligosaccharide itself is reduced. obtain. Reduction of such a heteropoly compound 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. For this reason, this quantification method is easy to apply to automation.

  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.

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
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
Ascorbic acid (special grade reagent): 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 of 5 mg [P] / liter.
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. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of D-fructose having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of ammonium molybdate solution was added and left for 7 minutes. The ammonium molybdate solution used here is a solution of hexammonium hexamolybdate tetrahydrate and potassium antimonyl tartrate trihydrate dissolved in distilled water. The concentration of antimonyl potassium tartrate trihydrate was adjusted to 20 g / liter and 0.8 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. Subsequently, 0.2 ml of D-fructose having a concentration of 400 g / liter was added in a state where the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of an ammonium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 the test water was determined based on the analytical curve created from the measured value, it was 1.94 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. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of D-arabinose having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of ammonium molybdate solution was added and left for 7 minutes. The ammonium molybdate solution used here is the same as that used in Example 1.

  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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of D-arabinose having a concentration of 400 g / liter was added in a state where the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of an ammonium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 1.98 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 potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of D-glucose having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of ammonium molybdate solution was added and left for 10 minutes. The ammonium molybdate solution used here is the same as that used in Example 1.

  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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of D-glucose having a concentration of 400 g / liter was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of an ammonium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 2.02 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 potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of sucrose having a concentration of 200 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of ammonium molybdate solution was added and left for 7 minutes. The ammonium molybdate solution used here is the same as that used in Example 1.

  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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of sucrose having a concentration of 200 g / liter was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of an ammonium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 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 potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of D-raffinose pentahydrate having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of ammonium molybdate solution was added and left for 7 minutes. The ammonium molybdate solution used here is the same as that used in Example 1.

  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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of D-raffinose pentahydrate having a concentration of 400 g / liter was added in a state where the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of an ammonium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 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 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of D-maltose monohydrate having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of lithium molybdate solution was added and left for 7 minutes. The lithium molybdate solution used here is obtained by dissolving lithium molybdate and antimony (III) oxide in distilled water. The concentration of lithium molybdate is set to 20 g / liter, and the concentration of antimony (III) oxide is adjusted. It is adjusted to 0.5 g / liter. The antimony (III) oxide used in preparing the lithium molybdate solution was previously dissolved in an appropriate amount of hydrochloric acid diluted with distilled water and adjusted to a concentration of 5% by weight.

  For each phosphate ion solution treated as described above, the absorbance at 650 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of D-maltose monohydrate having a concentration of 400 g / liter was added in a state where the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of a lithium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  About the test water after completion | finish of a heating, when the light absorbency of 650 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 1.88 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 ammonium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of lactose monohydrate having a concentration of 400 g / liter was added and left for 3 minutes. Furthermore, while maintaining the state heated to 95 ° C., 0.2 ml of calcium molybdate solution was added and left for 7 minutes. The calcium molybdate solution used here is obtained by dissolving calcium molybdate and antimony (III) chloride in distilled water. The concentration of calcium molybdate is set to 20 g / liter, and the concentration of antimony (III) chloride is adjusted. It is adjusted to 0.8 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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of lactose monohydrate having a concentration of 400 g / liter was added with the test water heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of a calcium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 the test water was determined based on the analytical curve created from the measured value, it was 2.16 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 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of galactose having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of potassium molybdate solution was added and left for 7 minutes. The potassium molybdate solution used here is obtained by dissolving potassium molybdate and antimony (III) oxide in distilled water. The concentration of potassium molybdate is set to 20 g / liter, and the concentration of antimony (III) oxide is adjusted. It is adjusted to 0.5 g / liter. The antimony (III) oxide used in preparing the potassium molybdate solution was previously dissolved in an appropriate amount of hydrochloric acid diluted with distilled water and adjusted to a concentration of 5% by weight.

  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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of galactose having a concentration of 400 g / liter was added with the test water heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of a potassium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 1.99 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 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of 1-kestose having a concentration of 400 g / liter was added and left for 3 minutes. Furthermore, while maintaining the state heated to 95 ° C., 0.2 ml of a disodium molybdate (VI) dihydrate solution was added and left for 7 minutes. The disodium molybdate (VI) dihydrate solution used here is a solution of disodium molybdate (VI) dihydrate and potassium antimonyl tartrate trihydrate in distilled water. VI) The concentration of disodium acid dihydrate was adjusted to 20 g / liter, and the concentration of potassium antimonyl tartrate trihydrate was adjusted to 0.8 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. 9, 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of 1-kestose having a concentration of 400 g / liter was added while the test water was heated to 95 ° C., and left for 3 minutes. Furthermore, 0.2 ml of a disodium molybdate (VI) dihydrate solution (similar to that used for preparing the calibration curve) was added while the test water was heated to 95 ° C. Heating was continued for 7 minutes.

  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 1.88 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 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of stachyose n hydrate having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of lithium molybdate solution was added and left for 7 minutes. The lithium molybdate solution used here was obtained by dissolving lithium molybdate and potassium antimony tartrate trihydrate in distilled water. The concentration of lithium molybdate was 20 g / liter, and potassium antimony tartrate trisodium was added. The hydrate concentration is adjusted to 0.8 g / liter.

  About each phosphate ion solution processed above, the absorbance at 830 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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of stachyose n hydrate having a concentration of 400 g / liter was added in a state where the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of a lithium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  About the test water after completion | finish of a heating, when the light absorbency of 830 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 1.92 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 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of isomaltulose having a concentration of 400 g / liter was added and left for 3 minutes. Furthermore, while maintaining the state heated to 95 ° C., 0.2 ml of calcium molybdate solution was added and left for 7 minutes. The calcium molybdate solution used here is obtained by dissolving calcium molybdate and antimony (III) oxide in distilled water. The concentration of calcium molybdate is set to 20 g / liter and the concentration of antimony (III) oxide is adjusted. It is adjusted to 0.5 g / liter. The calcium molybdate used in the preparation of the calcium molybdate solution was previously dissolved in an appropriate amount of hydrochloric acid diluted with distilled water to adjust the concentration to 5% by weight, and used in the preparation of the solution. Similarly, antimony (III) oxide was previously dissolved in an appropriate amount of hydrochloric acid diluted with distilled water to adjust its concentration to 5% by weight.

  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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of isomaltulose having a concentration of 400 g / liter was added while the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of a calcium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 test water was determined based on the analytical curve created from the measured value, it was 2.14 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 potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of maltulose monohydrate having a concentration of 400 g / liter was added and left for 3 minutes. Further, while maintaining the state heated to 95 ° C., 0.2 ml of potassium molybdate solution was added and left for 7 minutes. The potassium molybdate solution used here is a solution in which potassium molybdate and antimony (III) chloride are dissolved in distilled water. The concentration of potassium molybdate is 20 g / liter, and the concentration of antimony (III) chloride is increased. It is adjusted to 0.8 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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of maltose monohydrate having a concentration of 400 g / liter was added in a state where the test water was heated to 95 ° C., and left for 3 minutes. Further, 0.2 ml of a potassium molybdate solution (similar to that used when preparing the calibration curve) was added while the test water was heated to 95 ° C., and heating at the same temperature was continued for 7 minutes.

  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 test water was determined based on the analytical curve created from the measured value, it was 1.93 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 potassium peroxodisulfate having a concentration of 30 g / liter were added and heated at 95 ° C. for 40 minutes using a block heater. Subsequently, while maintaining the state heated to 95 ° C., 0.2 ml of lactulose having a concentration of 400 g / liter was added and left for 3 minutes. Furthermore, while maintaining the state heated to 95 ° C., 0.2 ml of a disodium molybdate (VI) dihydrate solution was added and left for 7 minutes. The disodium molybdate (VI) dihydrate solution used here is a solution of disodium molybdate (VI) dihydrate and antimony (III) chloride in distilled water. The concentration of disodium dihydrate was adjusted to 20 g / liter, and the concentration of antimony (III) chloride was adjusted to 0.8 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. 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)
The same test water as used in Example 1 (total phosphorus concentration 2 mg [P] / liter) was prepared. To this test water, 0.6 ml of 1M sulfuric acid 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. Subsequently, 0.2 ml of lactulose having a concentration of 400 g / liter was added while the test water was heated to 95 ° C., and left for 3 minutes. Furthermore, 0.2 ml of a disodium molybdate (VI) dihydrate solution (similar to that used for preparing the calibration curve) was added while the test water was heated to 95 ° C. Heating was continued for 7 minutes.

  About the test water after completion | finish of a heating, when the light absorbency of 900 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 (4)

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;
Oligos capable of producing aldoses having 5 carbon atoms, aldoses having 6 carbon atoms, ketoses having 6 carbon atoms and aldoses having 5 carbon atoms, aldoses having 6 carbon atoms or ketoses having 6 carbon atoms by decomposition into the test water having undergone step 1 Adding an aqueous solution containing a saccharide selected from the group consisting of sugars, and subsequently heating for a predetermined time; and
An aqueous solution containing an alkali metal salt or alkaline earth metal salt of molybdate hexammonium or molybdic acid and an antimony compound having an antimony valence of 3 is added to the test water that has undergone step 2 and maintained at 65 ° C. or higher. Step 3 and
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, maltulose or lactulose. A pretreatment method for the test water for quantifying total phosphorus contained in the 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;
Oligos capable of producing aldoses having 5 carbon atoms, aldoses having 6 carbon atoms, ketoses having 6 carbon atoms and aldoses having 5 carbon atoms, aldoses having 6 carbon atoms or ketoses having 6 carbon atoms by decomposition into the test water having undergone step 1 Adding an aqueous solution containing a saccharide selected from the group consisting of sugars, and subsequently heating for a predetermined time; and
For pretreatment of test water for determination of total phosphorus including   The pretreatment method for test water for the determination of total phosphorus according to claim 3, wherein the oligosaccharide is sucrose, maltose, lactose, raffinose, kestose, stachyose, isomaltulose, maltulose or lactulose.

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