Dechlorination deuterium-added gas chromatography-mass spectrometry method for short-chain and medium-chain chlorinated paraffin

A technology for chlorinated paraffin and analysis method, which is applied in the field of dechlorination and deuterium gas chromatography-mass spectrometry analysis of short-chain and medium-chain chlorinated paraffin, and can solve the problem of low chlorination site selectivity, difficult separation, deviation of analysis results, etc. It can solve the problem of complex spectrum and quantitative method, avoid mutual interference, and achieve the effect of accurate detection results.

Active Publication Date: 2014-12-03
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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Problems solved by technology

[0004] Due to the low selectivity of chlorinated paraffins in the industrial production process, the composition of SCCPs and MCCPs is complex, producing a large number of chlorinated homologues, enantiomers and diastereoisomers, which are difficult to separate on chromatography and retain Time superimposes on each other, which brings great difficulties to the accurate quantification of SCCPs and MCCPs
Currently, there are many analytical methods for chlorinated paraffins, such as gas chromatography (GC)-electron impact mass spectrometry (EI-MS), which can obtain the total amount information of chlorinated paraffins (including SCCPs, MCCPs and LCCPs). The component distribution information of each homologue, and SCCPs and MCCPs cannot be distinguished; gas chromatography (GC)-electron capture negative chemical source mass spectrometry (ECNI-MS) is currently the most commonly used method for analyzing environmental samples, but SCCPs and MCCPs are under ECNI conditions The response factor depends on the number of chlorine atoms and its position on the carbon chain, and some low-chlorinated components cannot be detected
When a mixture of SCCPs with different compositions is used as a quantitative standard, it will cause considerable deviation in the analysis results, even reaching more than 100%.
The carbon skeleton gas chromatography method uses hydrogen to reduce chlorinated paraffins to the corresponding alkanes under the condition of catalyst, but this method cannot obtain the chlorine content information required for studying the toxicity of chlorinated paraffins
In addition, there are comprehensive two-dimensional gas chromatography (GC×GC electron capture negative chemical source (ECNI) rapid scanning quadrupole mass spectrometry (qTOF MS), high performance liquid chromatography chlorine enhanced atmospheric pressure chemical ionization (CI APCI) ion trap mass spectrometry, etc., but There are also certain difficulties in the accurate quantification of SCCPs and MCCPs. So far, no accurate quantitative analysis methods for SCCPs and MCCPs have been established internationally.

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  • Dechlorination deuterium-added gas chromatography-mass spectrometry method for short-chain and medium-chain chlorinated paraffin
  • Dechlorination deuterium-added gas chromatography-mass spectrometry method for short-chain and medium-chain chlorinated paraffin
  • Dechlorination deuterium-added gas chromatography-mass spectrometry method for short-chain and medium-chain chlorinated paraffin

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preparation example Construction

[0031] 1) Preparation of anhydrous solvent: use ethylene glycol diethyl ether as a solvent, and reflux it with lithium aluminum hydride for more than 2 hours to remove water in ethylene glycol diethyl ether and alcohols and other impurities that may be reduced , collect 115-120 DEG C fraction after reaction is finished, put into desiccator and seal and preserve.

[0032] 2) Dechlorination and deuterium reaction of short-chain and medium-chain chlorinated paraffins: at a constant temperature of 50-120°C, in anhydrous ethylene glycol diethyl ether, short-chain and medium-chain chlorinated paraffins and deuterated aluminum Lithium undergoes dechlorination and deuterium reaction to generate deuterated alkanes corresponding to the substitution positions of the original chlorine. Add 100-1000 μL deionized water, 100-1000 μL sodium hydroxide solution with a mass concentration of 20%, and 200-2000 μL deionized water to quench the excess deuterated reducing agent in the reacted sample ...

Embodiment 1

[0040] Example 1 uses a chlorodecane standard solution with a carbon chain length of 10 and a chlorine content of 41.1% as a sample, and quantitatively analyzes it using the method of the present invention. The obtained mass spectrum is as figure 1 shown. Its molecular ion peak mass range is 143-148. Calculate the concentration of its deuterated alkanes according to its chromatographic peak area, and combine the chlorine content information of different chlorine substitution components of chlorodecane to calculate that the chlorine content in the sample is 41.2%, and its chlorine distribution characteristics are as follows figure 2 As shown, 3-chlorinated decane is the main one, followed by 4-chlorinated components, 2-chlorinated components and 5-chlorinated components, and there are also a small amount of 1-chlorinated and 6-chlorinated components. And if detect with the GC-ECNI-MS method that generally adopts at present, then because the low chlorinated component is corre...

Embodiment 2

[0041] Embodiment 2 adopts the industrial chlorinated paraffin product Chlorowax-52 as the analysis object, and adopts the method of the present invention to carry out its quantitative analysis. Its gas chromatogram is as image 3 As shown, the carbon chain length distribution ranges from 10 to 23, and chlorinated paraffins with carbon chain lengths of 14, 17 and 18 are the main components. Taking chlorinated alkanes with a carbon chain length of 14 as an example, selectively detect its mass number 199-209, such as Figure 4 shown. Calculate the concentration of its deuterated alkanes according to its chromatographic peak area, and combine the chlorine content information of different chlorine substitution components of chlorotetradecane and its relative mass fraction to calculate the chlorine content of SCCPs in the sample to be 48.9%, which is a medium-chain chlorination The chlorine content of paraffin was 47.6%, accounting for 15.3% and 60.2% of the mass concentration of...

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Abstract

The invention provides a method for detecting content of short-chain and medium-chain chlorinated paraffin. The method comprises: making a sample containing short-chain and medium-chain chlorinated paraffin and a deuteriation reducing reagent to have a deuterium-adding dechlorination reaction at 80-120 DEG C, so as to generate an alkane with corresponding deuterium substituting quantity; then performing water deactivation and alkali processing, and employing hexane to performing multi-time extraction on the sample, and concentrating and getting a constant volume; and employing gas chromatography-mass spectrometry to perform quantitative analysis on the deuterated alkane with different deuterium substituting quantity, so as to obtain concentration and distribution characteristic of homologue compositions of short-chain and medium-chain chlorinated paraffin with different carbon chain length and different chlorine substituting quantity. Chlorine content does not influence response factors in the method, the method effectively solves problems in a gas chromatography-electron capturing negative chemical source-mass spectrum method generally employed for analyzing short-chain and medium-chain chlorinated paraffin at present, and mutual interference of homologues is avoided, and the method is accurate in detection result and simple in operation, and can be used as a laboratory routine standard analysis method.

Description

technical field [0001] The invention relates to a method for detecting the content of short-chain and medium-chain chlorinated paraffins. Specifically, a deuterated reducing agent is used to replace the chlorine atoms of chlorinated paraffins with deuterium atoms to generate deuterated alkanes with a corresponding number of deuterium atoms. , through the method of gas chromatography mass spectrometry to analyze deuterated alkanes, according to the molar concentration of deuterated alkanes and the deuterium substitution degree, so as to achieve the accurate quantification of short-chain and medium-chain chlorinated paraffins. Compared with the reported analysis methods for short-chain and medium-chain chlorinated paraffins, this method does not have the influence of chlorine content on the response factor, and effectively solves the problem of gas chromatography-electron spectroscopy commonly used in the analysis of short-chain and medium-chain chlorinated paraffins. Capturing ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/88G01N30/06
Inventor 高媛陈吉平孙晓丽张海军田玉增
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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