JPH03218461A - Continuous analysis apparatus for trihalomethane - Google Patents

Abstract

PURPOSE:To make stable and rapid measurement with good reproducibility and high sensitivity by bringing a soln. mixed with a sample liquid of trihalomethane into contact with a carrier soln. mixed with nicotinic acid amide and NaOH via a microporous membrane. CONSTITUTION:The carrier soln. mixed 5A with the nicotinic acid amide and NaOH is sent to the the inner side of the tube of a separator 2. On the other hand, the 2nd soln. mixed 5B with the sample liquid contg. the trihalomethane and a sodium sulfite soln. or hydrazine sulfate is sent to the outer side of a separator 2 but these two solns. do not mix as the tube consisting of the microporous membrane is made of 'Teflon(R)' and has water repellency. However, the trihalomethane in the 2nd soln. has high volatility and, therefore, diffuses in the form of gas into the micropores. This gas penetrates into the carrier soln. and forms a fluorescent condensate by reacting with the nicotinic acid amide in the presence of the NaOH. The carrier soln. is then cooled 6 to about 10 to 30 deg.C to prevent the degradation in sensitivity by the temp. extinction of the fluorescence. After bubbles are removed, the fluorescent condensate is fluorescently detected and determined in a detecting section 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an analyzer for trihalomethane, a low-boiling organic chlorine compound, in solution, and particularly to a continuous analyzer capable of stably analyzing trihalomethane. [Prior art] In 1972, Room of the Netherlands reported that a considerable concentration of organic chlorine compounds existed in the downstream of the Rhine River, and that trihalomethanes such as chloroform accounted for a large proportion of these organic chlorine compounds. It was done. Furthermore, a study found that there was a significant difference in cancer incidence between people who drank tap water containing trihalomethanes and those who did not drink tap water in the Niéa-Orléans region of the lower Mississippi River basin. Trihalomethanes in tap water attracted attention. Since then, many studies have shown that trihalomethanes are formed due to organic compounds in water and chlorine used to ensure epidemiological safety. Under these circumstances, in March 1981, Japan set a target value for controlling the concentration of avian methane in tap water to 0.10.
The Ministry of Health and Welfare has notified the Ministry of Health and Welfare. In order to solve this trihalomethane problem and provide safe water to people, it is important to develop water treatment technology that does not produce trihalomethane, and it is also necessary to develop technology that accurately and quickly analyzes trihalomethane. become. As shown in Table 1, trihalomethane is a substance with a relatively low boiling point, so it easily volatilizes from sample water.The boiling point of chloroform, which is contained more than other trihalomethanes in tap water, is 61.2°C. and the lowest. Also, unlike other components, its concentration is low at ppb level. Therefore, in order to analyze these accurately, extreme care must be taken during the water collection, storage, and analysis operations. Table 1 Trihalomethane analysis methods include methods such as headspace method, solvent extraction method, purge trap method, etc. to concentrate trihalomethane by 11 minutes, and then quantitative determination using ECD gas chromatography, and flow injection method. A known method is to separate trihalomethane and then quantify it using fluorescence. [Problems to be Solved by the Invention] However, among these methods, the former method requires several hours for measurement and is time-consuming, and because it is a batch method, continuous analysis is not possible. Furthermore, as shown in FIG. 4, in the separation section 15, a sample solution containing trihalomethane is allowed to flow through a microporous membrane in contact with a carrier solution, which is an NaOH solution, and the trihalomethane is diffused into the NaOF+ solution. A nicotinic acid amide solution is added, trihalomethane and nicotinic acid amide are reacted in the reaction section 16, and then the reaction product is fluorescently quantified in the detection section 18 by Fujiwara reaction. At this time, in the constant temperature sections 17A and 17B, which are different from the separation section 15 and the reaction section 16,
'C maintained at a constant temperature of 90℃. This method has the advantage of being able to quantify trihalomethanes quickly and with high sensitivity.
However, this flow injection method has the following problems. In other words, since nicotinic acid amide is added after passing through the 11+ separation section, the carrier solution and nicotinic acid amide solution are insufficiently mixed and a stable output signal cannot be obtained. <<2>> When the carrier solution is heated in the reaction section 16, bubbles are generated in the carrier solution, and these bubbles interfere with fluorescence measurement, making stable measurement impossible. This invention was made in view of the above points, and its purpose is to improve the conventional flow injection method and provide a continuous trihalomethane analyzer that can stably and continuously quantify trihalomethane. [Means for Solving the Problem] According to the present invention, the above-mentioned purpose is to provide a first liquid feeding section 13, a second liquid feeding section 14, a separation section 2, a reaction section 4, and a constant temperature section 3.
, a defoaming section 7 , and a detection section 8 , and the first liquid feeding section supplies the first solution, which is a carrier solution containing a solution of sodium hydroxide and a solution of nicotinic acid amide, to the separation section. The second liquid feeding section supplies a second solution obtained by mixing the trihalomethane sample solution and the reducing agent solution to the separation section, and the separation section allows the first solution and the second solution to flow independently. The solution is brought into contact with the solution through a microporous membrane, the reaction section allows the first solution to flow and the trihalomethane transferred from the second solution is reacted with nicotinic acid amide, and the constant temperature section is connected to the separation section. The reaction section is housed to maintain the temperature of both sections at the same constant temperature, the defoaming section removes air bubbles in the first solution generated in the reaction section via a porous tube, and the detection section Fluorescently detecting the reaction product of trihalomethane and nicotinic acid amide in the reaction section, or 2) the reducing solution is a sodium sulfite solution, or 3) the reducing agent solution is a hydrazine sulfate solution. This is achieved by Nicotinic acid amide in the first liquid feeding section reacts with triyakuchi methane (chloroform 1 bromodichloromethane dibuchi mokukuchi methane, promoform) in the presence of NaOH to produce a photocondensate. It emits fluorescence when excited by excitation light. Sodium sulfite or hydrazine sulfate in the second liquid feeding section decomposes residual chlorine contained in the sample solution. The presence of residual chlorine interferes with the fluorescent reaction of the fluorescent condensate. Chlorine bound to organic compounds produces trihalomethanes with alkaline sodium sulfite, but acidic hydrazine sulfate does not produce trihalomethanes. Therefore, acidic hydrazine sulfate is used when the raw water has high dissolved organic matter or a large amount of tri-yakuchi methane intermediates.
The second liquid supply section can supply a standard solution for preparing a calibration curve instead of the sample solution via a switching cock. The separation section diffuses trihalomethane in the second solution into the first solution via a microporous membrane. The first and second solutions flow independently. As the Ith porous membrane, microporous Teflon (trade name of DuPont, same hereinafter) or microporous ceramics can be used. Volatile trihalomethane gas diffuses through the microporous membrane together with water vapor. The reaction section completes the reaction between trihalomethane transferred from the second solution to the first solution and nicotinic acid amide. The constant temperature section maintains the temperature of the separation section and reaction section at the same predetermined temperature. The temperature of the separation section and reaction section affects the fluorescence intensity. In both cases, the higher the temperature, the higher the fluorescence intensity, but if the temperature of the reaction zone exceeds 98°C, dissolved oxygen in the carrier solution will vaporize, increasing background noise, so 98°C is the critical temperature. The defoaming section consists of a porous tube, and when the carrier solution passes through it, air bubbles in the carrier solution are removed. As the porous tube, one made of Teflon is preferably used. The detection section irradiates excitation light to a fluorescent condensate resulting from the reaction of triyakuchimethane and nicotinic acid amide, and detects and quantifies the fluorescence emitted from the fluorescent condensate. 360-3 as excitation light
The wavelength of 80 nm is preferable, and the fluorescence wavelength is 450 to 470 nm.
A range of n is desirable. The excitation wavelength and fluorescence wavelength can be separated using filters, diffraction gratings, etc. [Operation] In the separation section, the trihalomethane diffuses into the first solution (carrier solution), which is a well-mixed mixture of nicotinic acid amide and NaOH solution, so that the carrier solution and trihalomethane are uniformly mixed. In the defoaming section, the air bubbles in the carrier solution are suppressed, eliminating the apparent increase in fluorescence intensity caused by air bubbles. [Example] Next, an example of this invention will be explained with reference to the drawings. FIG. 1 is a layout diagram showing a continuous trihalomethane analyzer according to an embodiment of the present invention. 30 in the first liquid feeding section 13
~40% concentration nicotinic acid amide solution and 0.2-0.4
NaOB solution with a concentration of 0.5 af/sin. It is sent to the mixing coil 5^ at a flow rate of . Nicotinamide solution and Na
The OH solution is well mixed with the mixing coil 5A to form a carrier solution, which is sent to the inside of the tube made of a microporous membrane in the separation section 2. On the other hand, when a sample solution containing trihalomethane is mixed with a 10% concentration sodium sulfite solution or a 1% concentration hydrazine sulfate solution, the peristaltic pump 1^. IB
Therefore, 0.75d/sin. It is sent to the mixing coil 5B at a flow rate of , and mixed well. The second solution produced by this mixing is sent to the outside of the tube made of a microporous membrane in the separation section 2. The tube made of a microporous membrane in the separation section 2 is made of Teflon and is water repellent, so the first solution and the second solution do not mix. However, the trihalomethane in the second solution is volatile and becomes a trihalomethane gas that diffuses through the hole and dissolves into the carrier solution. Trihalomethane reacts with nicotinic acid amide in a carrier solution in the presence of NaOFJ to form a fluorescent metal condensate. The carrier solution containing the condensate is sent to the reaction section 4,
The reaction is completed here. At this time, the separation section 2 and the reaction section 4 are maintained at a constant temperature of 95°C by the constant temperature section 3. Separation part 2
The temperature of the reactor and reaction section 4 is controlled by a single constant temperature section, which simplifies the equipment. Subsequently, the carrier solution is cooled to a temperature in the range of 10 to 30°C in the cooling section 6. This prevents a decrease in sensitivity due to temperature quenching of the fluorescence emitted from the fluorescent condensate. The carrier solution is then sent to the defoaming section 7. The defoaming section 7 is a porous tube made of Teflon, and preferably has a pore diameter of 1 to 3 pm and a length of 10 to 30 cm. After defoaming, the carrier solution is sent to the detection section 8, where the fluorescent metal condensate is detected and quantified by fluorescence. After photometry, the carrier solution passes through a back pressure coil 15 and is discarded. The fluorescence signal from the detection section 8 is data-processed by the calculation section 9, displayed on the display section 1l, and recorded in the recording section 12. The entire process of the continuous analyzer is l! It is controlled by the lIlII unit 10. Figure 2 shows the dependence of the relative fluorescence intensity on the separation temperature.
This is a diagram. The temperature of the reaction section is 98°C, and it can be seen that the higher the temperature of the separation section, the better. The temperature of the separation section can be raised to 98°C, which is the limit temperature of the reaction section. Setting the temperature of the separation section and reaction section to the same temperature of 98°C maximizes the sensitivity of the analyzer. Figure 3 shows the calibration curve when using chloroform as trihalomethane. Fluorescence intensity was measured 10 minutes after sample injection.

Table 2 shows the reproducibility when measuring tap water. The average value of 5 repeated measurements was 15 μg/1, and the coefficient of variation was 5.
．． It was 7 years ago. It can be seen that the reproducibility is improved compared to the coefficient of variation of measured values using conventional equipment, which is 8 to 10%. Table 2 [Effects of the Invention] According to the present invention, the first liquid feeding section, the second liquid feeding section,
It has a separation section, a reaction section, a constant temperature section, a defoaming section, and a detection section, and the first liquid feeding section is a carrier solution containing a mixture of a sodium hydroxide solution and a nicotinic acid amide solution. The second solution is supplied to the separation section, and the second liquid feeding section supplies the second solution obtained by mixing the trihalomethane sample solution and the reducing agent solution to the separation section, and the separation section flows independently. The first solution and the second solution are brought into contact with each other through a microporous membrane, and the reaction section is heated to 1J! While flowing the solution of 1, the triyacchi methane transferred from the second solution is reacted with nicotinic acid amide, and the constant temperature section accommodates the separation section and the reaction section and maintains the temperature of both sections at the same constant temperature. The defoaming section removes air bubbles in the first solution generated in the reaction section through a porous tube, and the detection section detects the reaction product of trihalomethane and nicotinic acid amide in the reaction section using fluorescent light. 2) In this case, the reducing agent solution is a sodium sulfite solution, or 3) Since the reducing agent solution is hydrazine sulfate, the first solution containing a well-mixed nicotinic acid amide and NaOH solution is detected in the separation section. Trihalomethane diffuses into the carrier solution, and the carrier solution and trihalomethane in the sample water are uniformly mixed without being affected by residual chlorine or dissolved organic matter in the sample water. In addition, in the de-pooling section, air bubbles in the carrier solution are removed, eliminating the apparent increase in fluorescence intensity caused by air bubbles. In this way, a continuous trihalomethane analyzer that can perform stable measurements with high sensitivity and speed with excellent reproducibility is obtained.

[Brief explanation of drawings]

Fig. 1 is a layout diagram showing a continuous analysis device for trihalomethane according to an embodiment of the present invention, Fig. 2 is a diagram showing the dependence of fluorescence intensity on temperature of the separation section, and Fig. 3 is a calibration curve for trihalomethane. Figure 4 is a layout diagram showing a conventional device.

Claims (1)

[Claims] 1) A first liquid feeding section, a second liquid feeding section, a separation section, a reaction section, a constant temperature section, a defoaming section, and a detection section; The liquid feeding section supplies a first solution, which is a carrier solution containing a solution of sodium hydroxide and a solution of nicotinic acid amide, to the separation section, and the second liquid feeding section supplies a sample solution of trihalomethane and a reducing agent. A second solution obtained by mixing the first solution and the second solution is supplied to a separation section, the separation section contacts the independently flowing first solution and the second solution through a microporous membrane, and a reaction section While the first solution is flowing, the trihalomethane transferred from the second solution is reacted with nicotinic acid amide, and the constant temperature section houses the separation section and the reaction section and maintains the temperature of both sections at the same constant temperature. The defoaming section removes air bubbles in the first solution generated in the reaction section through a porous tube, and the detection section fluorescently detects the reaction product of trihalomethane and nicotinic acid amide in the reaction section. A continuous analyzer for trihalomethane. 2) The continuous trihalomethane analysis device according to claim 1, wherein the reducing agent solution is a sodium sulfite solution. 3) The continuous trihalomethane analysis device according to claim 1, wherein the reducing agent solution is a hydrazine sulfate solution.