Method for analysis of thiophene in water by purge and trap coupled with GC-MS

Abstract

The invention discloses a method for analysis of thiophene in water by purge and trap coupled with GC-MS, the method is as follows: firstly, adding a proper amount of methanol as a preservative into a collected water sample, taking 20ml of the water sample into a sample bottle, adding 0.2g of sodium chloride, gently shaking to dissolve the sodium chloride, adding an internal standard solution, and sealing the sample bottle; putting the sample bottle into a purge and trap sample injector, setting purge and trap conditions, and performing purge and trap on the sample bottle to purge the thiophene out of the water to enter a gas chromatograph-mass spectrometer GC-MS; setting conditions of gas chromatography and mass spectrometry conditions of the gas chromatograph-mass spectrometer, analyzing the thiophene according to the set conditions, qualitatively analyzing the thiophene in the water sample according to retention time and ion fragments, and quantitatively analyzing the response value of the thiophene in the water sample by an internal standard method. By the purge and trap coupled with GC-MS, the thiophene is separated from the water, and quantitative and qualitative detection of the thiophene in the water are realized. The detection efficiency is improved, the experimental process is simplified, and the detection accuracy is improved.

Description

technical field [0001] The invention relates to the technical field of testing, in particular to a method for analyzing thiophene in water by purge-and-capture gas chromatography-mass spectrometry. Background technique [0002] Thiophene is a five-membered heterocyclic compound containing a sulfur heteroatom, its molecular formula C 4 H 4 S. Thiophene exists in crude benzene and crude naphthalene obtained by fractional distillation of coal tar. Crude benzene contains about 0.5% and is colorless. Since its boiling point is 84 ° C, which is close to benzene, it is difficult to separate them by distillation, so Thiophene is easy to enter the water body with industrial benzene pollution and becomes a common pollutant; although thiophene is moderately toxic, it has odor and strong irritation, and it is necessary to pay attention to the detection of thiophene. [0003] At present, there is no special detection method for thiophene in water. Generally, the determination method f...

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Problems solved by technology

Thiophene exists in crude benzene and crude naphthalene obtained by fractional distillation of coal tar. Crude benzene contains about 0.5% and is colorless. Since its boiling point is 84°C, which is close to benzene, it is difficult to separate them by distillation, so Thiophene is easy to enter the water body with the pollution of industrial benzene and becomes a common pollutant; although thiophene is moderately toxic, it has a foul smell and a strong irritant, so it is necessary to pay attention to the detection of thiophene

[0003] At present, there is no special detection method for thiophene in water. Generally, the determination method for thiophene in petroleum benzene (GB / T 3405-2011) is used; the whole process of spectrophotometry takes about 2 hours, the detection time is long, and the experimental process is cumbersome. And the experiment needs to use a large amount of concentrated sulfuric acid extraction, the operation is dangerous and the efficiency is low; while using gas chromatography (FPD) detection, it directly enters the sample into the gas chromatograph, and utilizes the high response of the FPD detector to sulfur compounds to complete the detection, but This method is not suitable for the detection of water samples, because the conventionally used gas chromatographic columns are not suitable for direct analysis of water samples, and the application range of gas chromatography (FPD) is limited, and most laboratories are not equipped

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