| Research Abstract |
1) Identification of urinary metabolites of human subjects exposed to omicron-dichlobenzene (omicron-DCB)
Urine samples were collected from three male workers exposed to omicron-DCB and they were analyzed using a gas chromatograph-mass spectrometer. 2,3-dichlorophenol (2,3-DCP), 3,4-dichlorophenol (3,4-DCP), 3,4-dichlorocatechol (3,4-DCC) and 4,5-dichlorocatechol (4,5-DCC) were detected in the all samples.
2) Quantitative determination of urinary metabolites of omicron-DCB using a high performance liquid chromatograph (HPLC)
First, urinary conjugated metabolites were hydrolyzed by concentrated hydrochloric acid, and the metabolites were extracted with diethylether. Next, 0.5 ml of the ethylether layr was separated, and 2.0 ml of methyl alcohol was added. The HPLC was connected to a column packed with LiChrospher 100 RP-18. For DCCs, the mobile phase was a mixture of acetonitrile, acetic acid and water (1 : 12 : 87). For DCPs, the mobile phase was a mixture of methyl alcohol, acetic acid a
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nd water (33 : 5 : 62). The effuents were monitored at 285 nm. The calibration curves were linear from 10 to 100 mg/l. The mean recovery rates of DCCs and DCPs were more than 90%.
3) Relation between exposure to omicron-DCB and urinary metabolites
In a plant symthesizing intermediate products for dyes, the 8-hr time weighted average (8-hr TWA) value for the exposure concentration of omicron-DCB and concetrations of urinary 3,4-DCC,4,5-DCC,2,3-DCP and 3,4-DCP were determined for 28 male workers. The concetrations of 3,4-DCC,4,5-DCC,2,3-DCP and 3,4-DCP inurine collected at the end of the workshift were shown to be linearly correlated to the 8-hr TWA value for the exposure concentration of omicron-DCB.Concequently, biological exposure monitoring can be done.
4) Quantitative Determination of Urinary Metabolites of omicron-DCB Using a Gas Chromatograph (GC)
Urine treatment was the same as that in the above HPLC method. The GC was connected to a capillary column was Shimadzu CBP-20. Helium was used as the carrier gas. The column temperature was programd from 50 to 220ﾟC at 3ﾟC/min. The injector and detector temperatures were 250ﾟC.The calibration curves were linear from 10 to 100mg/l. The mean recovery rates of 2,3-and 3,4-DCPs were more than 90%. Less
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