JPH0812186B2 - Continuous analyzer for trihalomethane - Google Patents

Description

TECHNICAL FIELD The present invention relates to an analyzer for trihalomethane, which is a low-boiling organochlorine compound in a solution, and more particularly to a continuous analyzer capable of stably analyzing trihalomethane.

[Conventional technology]

In 1972, Rook of the Netherlands reported that a considerable concentration of organochlorine compounds existed in the lower reaches of the Rhine, and trihalomethanes such as chloroform accounted for a large proportion of these organochlorine compounds. And further,
In the New Orleans area of the Lower Mississippi River, a study report was reported that there was a significant difference in cancer incidence between people who were drinking tap water containing trihalomethanes and those who were not. Trihalomethane was noted.

Subsequent studies have revealed that trihalomethanes are produced due to organic compounds in water and chlorine used to ensure epidemiological safety.

Under these circumstances, in Japan in March 1981, it was decided by the Ministry of Health and Welfare that the target control value for the concentration of trihalomethane in tap water be set to 0.10 mg / l.

In order to solve this trihalomethane problem and provide safe water to people, it is important to develop a water treatment technology that does not produce trihalomethane, and also to develop a technology that accurately and quickly analyzes trihalomethane.

As shown in Table 1, trihalomethane is a substance having a relatively low boiling point, so that it easily volatilizes from sample water. Especially, the boiling point of chloroform, which is higher than other trihalomethane substances in tap water, is the lowest at 61.2 ℃. Also, unlike other components, its concentration is low at the ppb level. Therefore, in order to analyze them accurately, it is necessary to pay close attention to the operations from sampling to storage to analysis.

Headspace method for analysis of trihalomethanes,
A method is known in which trihalomethane is separated and concentrated by solvent extraction method, purge trap method, etc., and then quantified by gas chromatography with ECD. Also, trihalomethane is separated by flow injection method and then quantified by fluorescence method. It has been known.

[Problems to be Solved by the Invention]

However, of these methods, the former has a problem that the measurement requires several hours and takes time, and since it is a batch method, continuous analysis cannot be performed. Further, as shown in FIG. 4, in the latter case, a sample solution containing trihalomethane is caused to flow in contact with a carrier solution, which is an NaOH solution, through a microporous membrane in the separation section 15 to diffuse and transfer the trihalomethane to the NaOH solution. A nicotinic acid amide solution is added, and trihalomethane and nicotinic acid amide are reacted in the reaction unit 16, and then the reaction product is fluorescently quantified by the Fujiwara reaction in the detection unit 18. At this time, the separation section 15 and the reaction section 16 are different from each other in a constant temperature section
It is maintained at a constant temperature of 60 ℃ and 90 ℃ in A and 17B, respectively. This method has the feature that trihalomethane can be quantified quickly and with high sensitivity. However, this flow injection method has the following problems. That is, (1) since nicotinic acid amide is added after passing through the separation section, the carrier solution and the nicotinic acid amide solution are not sufficiently 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 the fluorescence measurement, and stable measurement cannot be performed.

The present invention has been made in view of the above points, and an object thereof is to improve a conventional flow injection method and to provide a continuous trihalomethane analyzer capable of stably and continuously quantifying trihalomethane.

[Means for solving the problem]

According to the present invention, the above-mentioned objects are the first liquid feeding part 13, the second liquid feeding part 14, the separation part 2, the reaction part 4, and the constant temperature part 3.
And a defoaming unit 7 and a detection unit 8, and the first liquid feeding unit uses a first solution, which is a carrier solution obtained by mixing a sodium hydroxide solution and a nicotinic acid amide solution, as a separating unit. The second solution sending section supplies a second solution obtained by mixing a sample solution of trihalomethane and a reducing agent solution to the separating section, and the separating section independently flows the first solution and the second solution. Is contacted via a microporous membrane, and the reaction part causes the first solution to flow and the trihalomethane transferred from the second solution to react with nicotinic acid amide. The reaction part is housed and the temperature of both parts is kept at the same constant temperature. The defoaming part removes the bubbles in the first solution generated in the reaction part through the porous tube, and the detecting part The reaction product of trihalomethane and nicotinic acid amide in the reaction section is Fluorescence detection, or 2) where the reducing agent solution is a sodium sulfite solution, or 3) the reducing agent solution is a hydrazine sulfate solution. The nicotinic acid amide in the first liquid transfer section
Trihalomethane (chloroform, bromodichloromethane, dibromochloromethane, bromoform) in the presence of NaOH
Reacts with to form a fluorescent condensate. Fluorescence is emitted by these excitation lights. Sodium sulfite or hydrazine sulfate in the second liquid sending part decomposes residual chlorine contained in the sample liquid. 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, while acidic hydrazine sulfate does not produce trihalomethanes. Therefore, acidic hydrazine sulphate is used when the dissolved organic matter in the raw water is high or the trihalomethane intermediate is high. The second solution sending section can supply the standard solution for preparing the calibration curve instead of the sample solution through the switching cock. The separation part diffuses the trihalomethane in the second solution into the first solution through the microporous membrane. The first and second solutions flow independently. The microporous membrane is a microporous Teflon (Dupo
nt company trade name, the same applies hereinafter) and microporous ceramics can be used. The volatile trihalomethane gas, along with water vapor, diffuses through the microporous membrane.

The reaction part completes the reaction between the trihalomethane transferred from the second solution to the first solution and nicotinic acid amide. The constant temperature part maintains the temperatures of the separation part and the reaction part at the same predetermined temperature. The temperature of the separation part and the reaction part influences the fluorescence intensity. The higher the temperature, the higher the fluorescence intensity, but when the temperature of the reaction part exceeds 98 ° C, the dissolved oxygen in the carrier solution vaporizes and the background noise increases, so that 98 ° C becomes the limit temperature.

The defoaming part is made of a porous tube, and the bubbles in the carrier solution are removed when the carrier solution passes through.
As the porous tube, one made of Teflon is preferably used.

The detector irradiates the fluorescent condensate produced by the reaction of trihalomethane and nicotinic acid amide with excitation light to detect and quantify the fluorescence emitted from the fluorescent condensate. 360 to 380 as excitation light
The wavelength of nm is preferable, and the fluorescence wavelength is preferably in the range of 450 to 470 nm. The excitation wavelength and the fluorescence wavelength can be separated by using a filter, a diffraction grating, or the like.

[Action]

In the separation section, the trihalomethane diffuses into the first solution (carrier solution) in which the nicotinic acid amide and the NaOH solution are well mixed, so that the carrier solution and the trihalomethane are uniformly mixed.

In the defoaming section, the bubbles in the carrier solution are removed, so that the apparent increase in the intensity of fluorescence due to the bubbles disappears.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. First
FIG. 1 is a layout diagram showing a continuous analyzer for trihalomethane according to an embodiment of the present invention. In the first liquid sending section 13
40% strength nicotinamide solution and 0.2-0.4M strength NaO
H solution is 0.5 ml / m by peristaltic pump 1C and 1D respectively
It is sent to the mixing coil 5A at a flow rate of in. The nicotinic acid amide solution and the NaOH solution are well mixed by the mixing coil 5A and become a carrier solution, which is sent to the inside of the tube made of the microporous membrane of the separation section 2. On the other hand, the sample liquid containing trihalomethane was a peristaltic pump with 10% sodium sulfite solution or 1% hydrazine sulfate.
It is sent to the mixing coil 5B at a flow rate of 0.75 ml / min by 1A and 1B and mixed well. The second produced by this mixing
Solution is sent to the outside of the tube made of the microporous membrane of the separation part 2. Since the tube made of the microporous membrane of the separation part 2 is made of Teflon and is water repellent, the first solution and the second solution do not mix. However, the trihalomethane in the second solution is volatile, becomes a gas of trihalomethane, diffuses in the micropores, and dissolves in the carrier solution. Trihalomethane is a solution of nicotinic acid amide and Na in carrier solution.
Reacts in the presence of OH to form a fluorescent condensate. The carrier solution containing the condensate is sent to the reaction section 4, where the reaction is completed. At this time, the separation section 2 and the reaction section 4 are heated by the constant temperature section 3 to 95
It is kept at a constant temperature of ° C. Since the temperature of the separation section 2 and the reaction section 4 is controlled by a single constant temperature section, the apparatus becomes simple. Subsequently, the carrier solution is cooled to 10 to 30 ° C. in the cooling section 6. This prevents sensitivity deterioration 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 Teflon-made porous tube and preferably has a pore diameter of 1 to 3 μm and a length of 10 to 30 cm. After defoaming, the carrier solution is sent to the detection unit 8, and the fluorescent condensate is fluorescently detected and quantified. After photometry, the carrier solution is discarded through the back pressure coil 15. The fluorescence signal of the detection unit 8 is data-processed by the calculation unit 9, displayed on the display unit 11, and recorded by the recording unit 12. The entire process of the continuous analyzer is controlled by the control unit 10.

FIG. 2 is a diagram showing the temperature dependence of the relative fluorescence intensity on the separation portion. The temperature of the reaction section is 98 ° C. It can be seen that the higher the temperature of the separation section, the better. The temperature of the separation section can be increased up to the limit temperature of 98 ° C. of the reaction section. When the temperature of the separation section and the reaction section are the same at 98 ° C, the sensitivity of the analyzer is maximized.

FIG. 3 is a calibration curve when chloroform is used as trihalomethane. Fluorescence intensity was measured 10 minutes after sample injection.

Table 2 shows the reproducibility when tap water is measured. Average value of 15 μg / l after 5 repeated measurements, coefficient of variation 5.7%
Met. The coefficient of variation of measured values using a conventional device is 8 to
It can be seen that the reproducibility is improved as compared with 10%.

[Effect of the Invention] According to the present invention, it has a first liquid sending part, a second liquid sending part, a separating part, a reaction part, a constant temperature part, a defoaming part and a detecting part, The first liquid sending part supplies a first solution, which is a carrier solution obtained by mixing a sodium hydroxide solution and a nicotinic acid amide solution, to the separating part, and the second liquid sending part contains a trihalomethane sample solution. A second solution prepared by mixing a reducing agent solution is supplied to the separation section, and the separation section brings the first solution and the second solution, which flow independently, into contact with each other through a microporous membrane, Part flows the first solution and causes the trihalomethane transferred from the second solution to react with nicotinic acid amide, and the constant temperature part accommodates the separation part and the reaction part to keep the temperature of both parts at the same constant temperature. The defoaming section holds the bubbles in the first solution generated in the reaction section through a porous tube. And detecting the reaction product of the trihalomethane and nicotinic acid amide in the reaction section by fluorescence, or 2) the reducing agent solution is a sodium sulfite solution, or 3) reduction Since the reagent solution is hydrazine sulfate, trihalomethane diffuses into the first solution (carrier solution) in which nicotinic acid amide and NaOH solution are well mixed in the separation part, and carriers are not affected by residual chlorine or dissolved organic matter in the sample water. The solution and the trihalomethane in the sample water are mixed uniformly. In the defoaming section, the bubbles in the carrier solution are removed, and the apparent increase in the intensity of fluorescence due to the bubbles disappears.

In this way, a continuous analyzer for trihalomethane capable of performing stable measurement with excellent reproducibility with high sensitivity and speed can be obtained.

[Brief description of drawings]

FIG. 1 is a layout showing a continuous analyzer for trihalomethane according to an embodiment of the present invention, FIG. 2 is a diagram showing the temperature dependence of fluorescence intensity at the separation portion, and FIG. 3 is a diagram showing a calibration curve for trihalomethane. FIG. 4 and FIG. 4 are layout diagrams showing a conventional device. 1A, 1B, 1C, 1D: Peristaltic pump, 2: Separation part, 3: Constant temperature part, 4: Reaction part, 5A, 5B: Mixing coil, 6: Cooling part, 7: Defoaming part,
8: detection part, 9: calculation part, 10: control part, 11: display part, 12: recording part, 13: first liquid sending part, 14: second liquid sending part.

Front page continuation (72) Inventor Koji Kawakami 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Inventor Hiro Hoshikawa 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Inside the Electric Co., Ltd. (72) Inventor Masaru Kono 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Haruo Ito 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd.

Claims (3)

[Claims] 1. A first liquid transfer part, a second liquid transfer part, a separation part, a reaction part, a constant temperature part, a defoaming part, and a detection part. Part supplies a first solution, which is a carrier solution obtained by mixing a sodium hydroxide solution and a nicotinic acid amide solution, to the separation part, and the second liquid sending part supplies a trihalomethane sample solution and a reducing agent solution. The mixed second solution is supplied to the separation part, and the separation part brings the first solution and the second solution, which flow independently, into contact with each other through a microporous membrane, and the reaction part forms the first solution. Solution is allowed to flow and the trihalomethane transferred from the second solution is reacted with nicotinic acid amide, and the constant temperature part accommodates the separation part and the reaction part to keep the temperature of both parts at the same constant temperature, and defoams Part removes air bubbles in the first solution generated in the reaction part through the porous tube, and the detection part A continuous analyzer for trihalomethane, which is characterized by fluorescently detecting a reaction product of trihalomethane and nicotinic acid amide in the reaction section. 2. The continuous analyzer for trihalomethanes according to claim 1, wherein the reducing agent solution is a sodium sulfite solution. 3. The continuous analyzer for trihalomethanes according to claim 1, wherein the reducing agent solution is a hydrazine sulfate solution.