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OBJECTIVE: To screen the allergens of trichloroethylene-induced occupational medicamentosa-like dermatitis( OMDT) by patch test,and explore methods for OMDT auxiliary diagnosis and trichloroethylene( TCE) allergic population screening. METHODS: A total of 20 subjects diagnosed with OMDT were selected as case group,and 22 nonOMDT healthy workers exposed to TCE≥12 weeks were selected as control group. Different concentrations of TCE and its main metabolites such as chloral hydrate( CH),trichloroethanol( TCOH) and trichloroacetic acid( TCA) were used as allergens in a skin patch test in workers of these two groups. Another 20 new workers exposed to TCE < 12 weeks without OMDT were tested as validation group. They were tested with a patch test at a mass fraction of 15. 00% CH and follow-up observations were performed until 12 weeks of TCE exposure. RESULTS: The patch test of TCE,CH,TCOH and TCA were negative in the control group. In the case group,the patch test positive rate for 50. 00% TCE was 10. 00%,the patch tests were negative in 25. 00%,10. 00% and 5. 00% TCE. The CH patch test positive rate was 100. 00% with the CH mass concentrations of 15. 00%,10. 00% and 5. 00%. The TCOH patch test positive rates were 90. 00%,75. 00% and50. 00%,with the corresponding concentration of 5. 00%,0. 50% and 0. 05%. The TCA patch test positive rates were50. 00% and 0. 00% with the TCA concentrations of 5. 00% and 0. 50% respectively. When the mass concentration was5. 00%,the patch test positive rates in case group from high to low were CH,TCOH,TCA and TCE( P < 0. 01). And the patch test positive rates of CH and TCOH showed no statistical significant difference( P > 0. 05). The patch test positive rate of TCOH increased with increase of TCOH mass concentrations( P < 0. 01). The patch test positive rates for 5. 00%TCA was higher than that of 0. 50% TCA( P < 0. 01). The patch test positive rate in 0. 50% TCOH was higher than that of 0. 50% TCA( P < 0. 01). In the validation group,the patch test of 15. 00% CH was negative,and there was no OMDT case found during the follow-up 12 weeks of TCE exposure. CONCLUSION: The metabolites CH and TCOH of TCE may be the main allergens of OMDT after exposure to TCE. The CH and TCOH patch test can be an auxiliary diagnosis method for OMDT. The CH patch test could be used as a method for screening population allergic to TCE.
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Objective@#To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector.@*Methods@#With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15μm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation.@*Results@#The standard curves of TCE and TCOH showed significant linearity between 95.5μg/L-7640.0μg/L(r=0.9997)and 19.0μg/L-1520.0μg/L(r=0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions(RSD)were 2.5%-6.8%(n=6)and 1.6%-4.3%(n=6) respectively. The detect limit of TCE and TCOH were 2.10 μg/L and 0.56μg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss.@*Conclusion@#This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.