Research On The Determination Of Tetrahydrofuran In Human Urine By Headspace Solid-phase Microextraction And Gas Chromatography

Objective:Tetrahydrofuran is widely used in chemical,medicine and other industries,which was harmful to occupational people.The content of tetrahydrofuran in urine can be used as the biomarker of tetrahydrofuran,related limit for exposure and detection method have already established in foreign countries but not in China.The purpose of this research was to build up a method of headspace solid-phase microextraction and gas chromatography to detect tetrahydrofuran in urine,and to provide technical support for establishing biological exposure limits of tetrahydrofuran and for establishing national standard methods.Method:The headspace solid-phase microextraction method was used to heat the tetrahydrofuran from the urine sample with water bath,the tetrahydrofuran was volatiled and adsorbed on solid phase microextraction fiber,then did the extraction,concentration,enrichment of the tetrahydrofuran,injected the sample to the gas chromatograph with the solid phase micro-extraction handle,after that,desorbed the tetrahydrofuranon solid phase microextraction fiber for qualitative and quantitative analysis.The extraction fiber,extraction time,extraction temperature,extraction agent and parameters of gas chromatograph were optimized.The retention time was used for qualitative analysis and peak area for quantitative analysis.The methodology performance of the limit of detection,linear range,accuracy,the relative standard deviation were determined and studied for the established method.Samples from THF occupational exposed population and samples from non-occupational exposed population were verified through this method.Results: The analysis condition was optimized as follows: 5.0ml urine sample was transferred to the analysis vial containing 2.50 g anhydrous sodium sulfate,shaken and put in a water bath with a temperature of 40?,and the solid-phase microextraction handle was inserted into the analysis vial with the extraction fiber exposing to the gas phase in the top of the analysis vial,10 min later,take back the extraction fiber,remove the solid-phase microextraction handle,immediately insert into the gas chromatograph sample to detect.Gas chromatograph conditions as follows: the chromatographic column is FFAP capillary column;and the detector is hydrogen flameionization detector(FID);injection port temperature is 230 ?;column temperature is80 ?;the detector temperature is 240 ?;split ratio is 10:1;the carrier gas(N2)flow is 40 ml/min.The methodology parameters were as follows: Under the optimizedexperimental conditions,the detection limit of tetrahydrofuran in urine was 0.0055 mg/L,the regression equations of standard curves of the tetrahydrofuran was y=90.47x+4.46(r=0.9998).The results showed that,for tetrahydrofuran,the mean recovery percentages range at three levels of concentration were 92.6%~101.1%,The relative standard deviation(RSD)which expressed the precision for intra-day were7.62%~8.76%,for inter-day were 6.29%~7.26%.The urine samples were stable for at least 14 days when stored at 4? with a biodegradation <10%.Urine of occupational persons selected in end of the shift were determined by the method established in this paper,revealed a concentration of 0.539 mg/L ~1.887 mg/L,the concentration were under contrlol according to the reference of USA ACGIH,namely 2 mg/L.Meanwhile,tetrahydrofuranin were not detectable in urine of nonoccupational person.Conclusion:The methods of head space solid phase gas chromatography developed possessed the characteristics of easy handling,lower detection limit and accuracy.This method can meet the requirements of our country's indicators of determination method of biological materials.The field application shows that this method is feasible and can be used for the workers who exposed to tetrahydrofuran.