| Objective Although Pentachlorophenol(PCP)has moderate toxicity and accumulative effect,it was used widely as excellent antiseptics,insecticides and herbicide,and had been used as effective medicine to kill schistosomes in China.PCP content in urine was measured as biological monitoring markers of occupational exposures.The biological limit of PCP(in urine)is 2mg/g Cr evolved by The United Stated government industrial health expert meeting(ACGIH)and 0.64 mmol/mol or 1.5 mg/g Cr in China(WS/T 264-2006).The methods of high performance liquid chromatography(HPLE)and spectrophotometric was specified as government standard to detect the PCP contents in urine in China,1996.However,both of HPLE and spectrophotometric method cannot guarantee the high precision and accuracy of results,and the pretreatment of sample was too much complex to make results accurately.Therefore,in the present study,we explored a more advanced method,headspace solid phase micro-extraction coupled with gas chromatography,to make the detection of PCP contents in urine accurately and rapidly,and then to promote the improvement of government standard.Methods The sample was pretreated by headspace-solid phase micro-extraction(SPME),and then the extraction head was directly inserted into the gas chromatograph inlet sample for quantitative analysis.The conditions such as the equilibrium time,equilibrium temperature,salting-out agent and gas chromatographic conditions in headspace-solid-phase micro-extraction were optimized by single factor rotation experiment and orthogonal design experiment,and then the range,detection limit,quantitation limit,accuracy,precision,and actual sample application performance was tested to determine whether it can meet the methodology and practical application requirements.The urine samples of volunteers and male SD rats,which were fed with drinking water containing pentachlorophenol,were tested to verify the reliability of the method.Furthermore,in order to evaluated the uncertainty and measured the reliability of results comprehensively,this method was used to determine the pentachlorophenol contents in urine with a certain concentration and calculate the uncertainty.Results The optimal determination conditions were as follows: 5ml urine sample and 2.0g sodium chloride were mixed in the head space bottle.The 100μm PDMS extractor was used to extract in the constant temperature water at 80 ℃ for 30 min.Then the fiber coating was directly removed and inserted into a gas chromatography sampler,and the adsorbed material on the coating was analyzed for 5 min.Gas Chromatography was set as follows: HP-5 capillary column(30m × 0.32 mm × 0.25μm);electron capture detector(ECD);injection port temperature was set to 280 ℃;detector temperature was set to 300 ℃;oven temperature was set to 40 ℃ for 2min,and then heated to 240 ℃ at the speed of 20 ℃ / min,and keep stable for 3min;with no shunt.Methodology performance index: the limit of detection was 0.50 mg / L ～ 5.00 mg / L,the limit of quantification was 0.030 mg / L,the determination range was 0.50 mg / L ～ 5.00 mg / L,the linear regression equation was y = 10549 x + 175.77,r = 0.9993,the average recoveries of the three standard concentrations(low,medium and high)were 97.6% ～ 103.7%,the relative standard deviations of within-day and between-day precision was 1.63% ～ 6.78%,the samples can at least be stored in refrigerator at 4℃ for 14 days,and the loss rate of the determined was < 10%.The method was applied to detect the pentachlorophenol in urine samples of volunteers;the recoveries of the urine samples after experiments were as follows: 96.0% ～ 105.0%.The pentachlorophenol solution with the concentration of 1.50 mg / L was used to feed SD rats,and blank control group was also prepared.First we collect urine samples from SD rats,and then apply the established method to detect.The content of pentachlorophenol was detected in SD rats’ urine samples and ranges from 0.12 mg / L to 0.47 mg / L,but not found in control group.The method was used to determine the urine with pentachlorophenol in the concentration of 1.45 mg / L.The combined standard uncertainty was 0.04 mg / L and the expanded uncertainty was 0.08 mg / L.The use of this method to determine the urinary pentachlorophenol content should be reported as:(1.45 ± 0.08)mg / L.The determined urinary pentachlorophenol content in this method should be reported as:(1.45 ± 0.08)mg / L.Conclusions The method of headspace solid-phase micro-extraction-gas chromatography for the determination of pentachlorophenol in urine was simple,rapid,accurate,accurate and stable.The results were accurate and reliable.All the indexes met the occupational health standard Guidelines for the determination of chemical substances in biological materials(Part 1: Guidelines for the determination of chemical substances in biomaterials "(GBZ / T 210.5-2008).In the practical application,the detection of urine samples from college students’ volunteer urine samples and the extraction of urine samples from quantitative pentachlorophenol solution in SD rats were feasible and could be used for the detection of pentachlorophenol in occupational exposure to pentachlorophenol.The influence factors of uncertainly in experiment were determined by identifying and analyzing the sources of uncertainly in the detection processes,and then control the critical procedure,in order to provide a theoretical basis for improving the accuracy of pentachlorophenol detection in urine. |
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