A method for the analysis of thiophene in water by purge and trap gas chromatography

Abstract

The invention discloses a method for analyzing thiophene in water by purging and trapping gas chromatography. The method firstly adds an appropriate amount of methanol into the collected water sample as a preservative, takes 20ml of the water sample, puts it into a sample bottle, and adds 0.2g of sodium chloride , gently shake to make it dissolve, then add the internal standard solution and seal the cap; put the sample bottle in the purge and trap injector, set the purge and trap conditions to purge and trap the sample bottle, the water sample Thiophene is purged from the water and enters the GC / MS; set the gas chromatography and mass spectrometry conditions of the GC / MS, analyze the thiophene according to the set conditions, and make a qualitative analysis of the thiophene in the water sample according to the retention time and ion fragments Analysis, using the internal standard method to quantitatively analyze the response value of thiophene in water samples. The method combines purge and trap with a gas chromatography-mass spectrometer to separate thiophene from water, realize quantitative and qualitative detection of thiophene in water, improve detection efficiency, simplify experiment process, and improve detection accuracy.

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...

AI Technical Summary

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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