Environmental and Biological Monitoring of 2,2-Dichloro-1,1,1-trifluoroethane (HCFC-123)

2,2-Dichloro-1,1,1-trifluoroethane (HCFC-123, CAS No. 306-83-2), a colorless liquid with a light ether odor and boiling point of 27.6℃ is a substitute for the strong ozone-depleting chlorofluorocarbon, trichlorofluoromethane. Recent case reports clearly indicate that repeated exposure to a high concentration of HCFC-123 causes severe liver damage 1,2). This report describes a method of determining HCFC-123 in the environment and the usefulness of trifluoroacetic acid in urine (TEA-U) as a biological monitoring parameter of HCFC-123. Materials and Methods HCFC-123 measurement was investigated with a sampling tube containing 400 mg activated charcoal adsorbent (Jumbo Type; Shibata Scientific Technology, Ltd.), Tedlar(R) bag, (1L, film thickness 50 μm; GL Sciences Inc.), an air sampling pump (PMD-05D; Shibata Scientific Technology, Ltd.), HCFC-123 compressed gas in cylinders calibrated at 101 and 1,114 ppm (Taiyo Toyo Sanso Co., Ltd.) reagents (dichioromethane, sulfuric acid and dimethyl sulfide; Wako Pure Chemical Industries, Ltd.) and gas chromatography. The flow rate of the air sampling pump was set at 0.1 liter/min. To measure the breakthrough time of the sampling tube, 1,114 ppm, 487 ppm or 101 ppm HCFC-123 was continuously passed through the sampling tube until the HCFC-123 concentration in the downstream of the sampling tube exceeded 5 ppm. The desorption efficiency was assessed after 101 or 12 ppm HCFC-123 was sampled for 10 min and desorbed with 2 ml dichioromethane for more than 1 h. To determine the storage stability conditions for HCFC-123 samples, the sampling tubes were exposed to 10 ppm HCFC-123 for 10 min, tightly sealed, kept at room temperature (20℃)or in a refrigerator (5℃)and monitored for the HCFC-123 concentration for up to 25 days. Similarly, 12 or 101 ppm HCFC-123 was collected in the Tedlar(R) bags and kept at room temperature, and the concentration of HCEC-123 was traced for 84 h. Analysis of TFA-U was performed by the method of Maiorino et al. 3) Briefly, urine, sulfuric acid and dimethyl sulfide were mixed in a cooled, tightly capped vial. After the bottle was heated in boiling water for 20 min to form methyl TFA, it was kept at 30℃ for 20 min, and then 1 ml of the head space gas was injected into GC.