KR100504303B1 - Determination Method of Ethylenethiourea, Maleic Hydrazide and Isopropylmethylphosphonate in Water Samples - Google Patents

Abstract

In the present invention, a method of concentrating to simultaneously analyze three harmful substances such as ethylenethiourea, maleic acid hydrazide, and isopropylmethylphosphonate contained in drinking water and water samples was used, and after concentration, iodide methyl and acetone were concentrated. After the reaction by using the three kinds of harmful substances, characterized in that after determining the concentration of methyl derivatives. The method consists in analyzing the concentrations of the above three hazardous substances using gas chromatography (GC) or gas chromatography (GC) -mass spectrometry (MS). When analyzing in a water sample by the method of the present invention, it is possible to simultaneously obtain excellent sensitivity, shortening and simplicity of analysis time, economy, and prevention of secondary contamination generated when using an extraction solvent.

Description

Determination Method of Ethylenethiourea, Maleic Hydrazide and Isopropylmethylphosphonate in Water Samples}

The present invention is a detection method for simultaneously detecting three harmful substances such as ethylene thiourea, maleic acid hydrazide, isopropyl methyl phosphonate in drinking water and water samples, more specifically using the vacuum rotary evaporator After concentration, methyl iodide is reacted under a constant reaction time and temperature to derivatize the three hazardous substances, which are then directly subjected to gas chromatography (GC) or gas chromatography / mass spectrometry (GC / MS). The present invention relates to a detection method that can be effectively and widely applied to monitoring harmful substances remaining in traces in water quality due to its excellent sensitivity, shortening and simplicity of analysis time, and economic efficiency.

Of the three substances to be analyzed, ethylenethiourea and maleic acid hydrazide are mainly used as pesticides and have been widely used worldwide because they are relatively inexpensive and can be effective in small amounts [J. Chromatography A 765 (1997) 31-38]. Isopropylmethylphosphonate is also a toxic substance known to cause paralysis in the nervous system [J. Chromatography B 701 (1997) 9-17]. Due to the abuse of these harmful substances, it is known that they penetrate rivers, lakes, groundwater, soil, etc. after use and pollute the environment.

All three substances analyzed in the present invention are ethylenethiourea, maleic acid hydrazide, and isopropylmethylphosphonate. These pesticides and other pests have never been analyzed simultaneously. In addition, these three materials are hardly soluble in common organic solvents, and their solubility in water is very low. For this reason, extraction is very difficult. These three pesticides are characterized by having a hydroxyl group (-OH) and an amino group (-NH), and thus have a high polarity. However, these three pesticides have problems in trace analysis when analyzed by themselves, or cannot be detected by gas chromatography. There is a case. For this reason, in order to analyze these materials, a method of mainly analyzing by using liquid chromatography or detecting by using NPD (nitrogen-phosphorus detection) as a detector has been used. However, this analysis has been pointed out that the detection limit is relatively high, and the use of various harmful reagents can cause secondary environmental pollution. Therefore, there has been a demand for a stable detection method that can be analyzed quickly, economically and in trace amounts.

Therefore, an object of the present invention is to analyze the three harmful substances such as ethylene thiourea, maleic acid hydrazide, and isopropylethyl phosphate in drinking water and water samples in a quick, economical and trace amount, and also It is to provide a stable detection method for simultaneously detecting harmful substances.

In the present invention, in order to effectively analyze the three harmful substances that are difficult to extract from drinking water and water samples, the water samples are directly evaporated and concentrated, and then the three hazardous substances are reacted using methyl iodide and acetone. After derivatization, it is characterized by a simultaneous detection method that analyzes trace concentrations of three hazardous substances by direct gas chromatography or gas chromatography / mass spectrometry.

The present invention will be described in detail as follows.

In the present invention, a method of concentrating to analyze three substances from drinking water and water samples was conducted. These materials are difficult to extract with a solvent because the extraction rate with respect to the organic solvent is very low. In the present invention, 5-10 ml of water is completely dried using a direct vacuum rotary evaporator without using an organic solvent, and then all three harmful substances are derivatized using methyl iodide. This derivatization reaction is shown in Scheme 1 below.

The reaction time of the three substances with methyl iodide is important in the derivatization of Scheme 1, and the amount of methyl iodide is about 50-150 μl, preferably 50 μl, per 10 ml of the sample, and the reaction temperature is 60 −. 90 ° C., preferably 90 ° C., is suitable. The reaction time is about 30-120 minutes, and preferably 60 minutes, whereby the derivatization reaction is carried out to obtain the compound represented by Scheme 1. Acetone is sufficiently added in the reaction. In addition, potassium carbonate is used in order to create an alkaline atmosphere at the time of reaction. The method is an optimal condition for derivatizing the three materials and provides better detection limits with better sensitivity and selectivity for gas chromatography or gas chromatography / mass spectrometry.

Analysis of the derivatized three hazardous substances is carried out using gas chromatography or gas chromatography / mass spectrometry, specifically injected into gas chromatography, using a gas inert to oxidation as the mobile phase. The gas which can be used as the mobile phase can be any conventional gas used for gas chromatography. Preferred are nitrogen, helium and hydrogen which are inert to oxidation. The length and the inner diameter of the column can be a column having a medium polarity.

Hereinafter, the present invention has been described in more detail based on the following examples, but the present invention is not limited to the following examples.

<Example>

<Example 1>

Five blank test tubes were prepared, and 50 μl of 10 μg / ml standard solution of three substances such as ethylenethiourea, maleic acid hydrazide, and isopropylmethylphosphonate was added to each test tube, and ethyl was used as an internal standard. After adding 10 μl / ml of thiophyllin solution, add 50 μl of methyl iodide, ethyl iodide, and propyl iodide to each of three test tubes, and add 150 μl of acetone. About 3 mg of potassium carbonate powder was added thereto. The progress of this reaction is shown in Example 3 in detail. In addition, 50 μl of bis (trimethylsilyl) trifluoroacetamide (1% TMCS) and 50 μl of ethyl acetate are added to another test tube. In the last test tube, 50 μl of N- (tert-butyldimethylsilyl) -N-methyltrifluoroacetamide and 50 μl of ethyl acetate were added, and each was reacted at 80 ° C. for 1 hour.

As a result, N- (tert-butyldimethylsilyl) -N-methyltrifluoroacetamide reaction did not occur among the above five reactions, and the other four reactions were carried out, except for methyl iodide. Low and only reacted with the product after derivatization.

<Example 2>

Prepare two 25 ml separatory funnels, add 10 ml of distilled water, and add 50 µl of 10 µg / ml standard solution of three harmful substances such as ethylenethiourea, maleic acid hydrazide, and isopropylmethylphosphonate. 10 μg / ml of ethylthiophylline solution, which is an internal standard, was added. To achieve the salting effect, 2 g of anhydrous sodium sulfate was added, followed by 2 ml of ethyl ether and methylene chloride, respectively. After shaking for 15 minutes, it was extracted. After the extraction, the water layer was removed, and then the solvent layer extracted was dried. 50 μl of methyl iodide and 150 μl of acetone were added to 3 mg of potassium carbonate powder to enter the derivatization process. After heating at 80 ° C. for 1 hour, the reaction was completed and cooled, dried under nitrogen again, and the sample was dissolved again with 100 μl of ethyl acetate solution, followed by direct injection into 2 μl of gas chromatography. In this embodiment, the extraction rate according to the extraction solvent is intended. The results are as shown in FIG. 1 and the extraction using the solvent was hardly performed. Only the vacuum rotary evaporator showed good results.

<Example 3>

Using a methyl iodide, which is the optimum condition obtained in Examples 1 and 2, as a reaction reagent, 2 µl of a solution obtained by reacting at a reaction time of 60 minutes and a reaction temperature of 80 ° C was taken, and a gas chromatography or gas chromatography / mass spectrometer Etc., and preferably, injected into a gas chromatography / mass spectrometer to obtain chromatograms of peaks of trace amounts of three harmful substances and internal standards as shown in FIG. Figure 3 shows the mass spectrum of the three derivatized harmful substances, the molecular weight and characteristic fragment ion of each derivatized is well represented. The instrument used to determine the concentrations of these three hazardous substances is Hewlett-Packard's 5972 mass spectrometer and 5890 plus gas chromatography connected thereto. The ionization method used was electron impact (EI) and the temperature of the ion source was 280 ° C. SIM (Selected Ion Monitoring) mode was used for quantification, and m / z 130, 74 and 69, which are base peaks for ethylenethiourea, were used, and m for maleic acid hydrazide. / z 140, 69, 112 and the like were used, and isopropylmethylphosphonate was m / z 137, 111, 93. For internal standards m / z 208 was used. The column used for the analysis was an ultra 2 column having a length of 25 m, an inner diameter of 0.25 mm, a film thickness of 0.25 μm, helium as the mobile phase gas, and a flow rate of 0.7 ml / It was minutes. The temperature of the column was initially raised to 200 ° C. at a rate of 10 ° C./min without the time of staying at 100 ° C., and further raised to 300 ° C. at a rate of 20 ° C./min. The temperature of the sample inlet was 250 ° C. and the temperature of the gas chromatograph and mass spectrometer connection was 280 ° C.

<Example 4>

Take 10 ml of sample from some water purification plant, add 10 µl / ml of ethylthiophylline, an internal standard, and completely dry it using vacuum rotary evaporator. 50 µl of methyl iodide and 100 acetone are added to the residue. After adding 60 μl, heating at 80 ° C. for 60 minutes, the reaction was completed, cooled, dried under nitrogen again, dissolved in 100 μl of ethyl acetate, and then 2 μl was directly injected into gas chromatography for analysis. The calibration curve for quantifying three harmful substances through this analytical method using a mass spectrometer is as shown in Figure 4 and showed a good linearity in the concentration range of 0.2 ~ 5.0 ㎍ / ℓ.

As described above, the present invention makes it possible to effectively analyze three harmful substances in water samples, which are difficult to simultaneously extract, and have selective and excellent sensitivity to gas chromatography or gas chromatography / mass spectrometer. It also provides optimum analytical conditions for analysis with gas chromatography / mass spectrometers commonly used in the analysis of materials. Therefore, when using the present invention, it is possible to satisfy the excellent sensitivity, reproducibility improvement, accuracy, shortening of analysis time, low cost and simplicity. It can be widely applied to the analysis of environmental samples, especially water samples.

Figure 1 shows the extraction recovery rate according to the extraction solvent and concentration in the present invention.

2 shows chromatograms of three herbicides analyzed in the present invention by gas chromatography / mass spectrometry.

Figure 3 shows the mass spectrum of the three herbicides derivatized in the present invention.

Figure 4 shows the calibration curve for quantification in the present invention.

Claims (6)

After concentrating the drinking water or the water sample, the three harmful substances remaining in the drinking water or the water sample, ethylenethiourea, maleic acid hydrazide, and isopropylmethylphosphonate, are 30 to 30 to 60 ° C. under alkaline atmosphere. Ethylenethiourea, maleic acid hydrazide, isosome remaining in drinking water or water samples, characterized by determining the concentration of the three substances after reacting with methyl iodide and acetone for 120 minutes to determine the concentration of the three substances Method for simultaneously analyzing propylmethylphosphonate. The method of claim 1 wherein the drinking water or water sample is concentrated directly in vacuo without the use of an organic solvent. The method according to claim 1, wherein 50 to 150 µl of the methyl iodide is used per 10 ml of the sample. A method according to claim 1, characterized in that it is derivatized at a temperature of 80 to 90 ° C. The method of claim 1 wherein the derivatization is for 40 to 60 minutes. The analysis method according to any one of claims 1 to 5, which is performed using a gas chromatography / mass spectrometer that analyzes the concentration in the water quality samples of the three hazardous substances.