| Trichlorethylene, n-hexane, benzene and toluene are widely used as organic solvent in the yield of industrial and scientific research. In some certain occupational workplaces, such as electronics, rubber, plastics and metal industries, the excessive use of trichlorethylene, n-hexane, and BTEXwas very serious. After inhale these organic solvents they may cause varying degrees of damages of the neurological, respiratory, reproductive, cardiovascular, skin, blood and other systems of human body. These organic solvent can be metabolized by the body and the metabolites can be find in the urine and blood. To monitor the metabolites in the urine can objectively reflect the level exposure of body toharmful substances and the degree of intoxication, but also can provide an important basis, for the diagnosis and treatment of occupational poisoning. So, to establish a method to monitor the metabolites of the toxic organic solvents, trichlorethylene, n-hexane, benzene and toluene used in electronics, rubber, plastics and metal industrieswas necessary.In this stuty, a high performance liquid chromatographic method was established for the determination of trichloroacetic acid basing on an interfacial reaction and the TCA was enriched purified at the same time. A UV absorbing group was lead in of TCA by the interfacial reaction with pyridine. In the reaction, TCA reacted with pyridine continually via diffusion and the reaction product finally entered into the upper organic phase and as the volume of pyridinen was much smaller than urine sample, the TCA was greatly enriched. The interfacial reaction conditions and chromatographic separation onditions were optimized and the optimal rection conditions were:pyridine derivative reagent volume was 0.5 mL, alkali concentration was 30%, reaction interface diameter wasl cm, the reaction temperature was 70 ℃ and the reaction time was 1.5 h; the optimal chromatographic conditions were: ZORBAX Eclipse XDB-C18 column for separation, a system composed of methanol and water acted as the mobile phase using a isocratic elution style as Vmethanol:Vwater=80:20 with the flow rate was 0.8 mL/min, the maximum absorption wavelength was 360 nm and the injection volumn of 10 μL, the column temperature was 30 ℃.Under the optimal chromatographic conditions, the four components could be well separated and simultaneously detected in 14 min, the established method was appropriate for the simultaneous separation and detection of the four components. Under the optimized conditions, the detection limit was 0.1 ng/mL (S/N= 3), the recovery rate was 91.9%～105% and the relative standard deviation was 3.6%.The study also established a pre-column derivatization-DLLME-High Performance Liquid Chromatography for the detection of 2,5-hexanedione, phenol and o-cresol in urine metabolized by n-hexane, benzene and toluene. As there was no strong UV absorption group in 2,5-hexanedione molecule, a pre-column derivatization was conducted and the optimized derived conditions were:the concertration of derivatization reagent was ten times of 2,5-hexanedione, the reaction temperature was 70 ℃ and the reaction time was 20 min. The optimum chromatographic conditions were:ZORBAX Eclipse XDB-C18 column for separation, the mobile phase was consisted of methanol and water using a gradient elution style with the flow rate was 0.8 mL/min; the detected wavelength for each component was changing with each retention time and the injection volumn of 10 μL, the column temperature was 30 ℃. Under the optimal chromatographic conditions, the three components could be well separated and simultaneously detected in 15 min. Meanwhile, in order to lower detection limit of the three target components, an DLLME was established for the simultaneous extraction and enrichment of the three components 2,5-hexanedione, phenol and o-cresol in urine.The optimal pretreatment conditions were:the extraction solvent was 300 μL chloroform,1.0 mL isopropanol as dispersive solvent, the extraction time was 10 min and the NaCl was added with 0.1 g. Under the optimal pretreatment conditions, the detection limit of three components ranging from 0.3-0.7 ng/mL (S/N= 3), the spiked recoveries were 89.1% ～104% and the relative standard deviation range from 2.4 to 4.4%.The experimental results show that the established method to determine TCA and 2,5-hexanedione, phenol and o-cresol metabolized by trichloroethylene, n-hexane, benzene and toluene for the electronic, rubber, plastics and metal industries was simple, rapid, sensitive, accurate, and environmental friendly and it could meet the requirment of biological monitoring. |
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