CHARACTERIZATION OF TOXAPHENE BY HIGH-RESOLUTION GAS-CHROMATOGRAPHY COMBINED WITH HIGH-RESOLUTION MASS-SPECTROMETRY AND TANDEM MASS-SPECTROMETRY

We examined the use of high resolution gas chromatography-electron ion ization high resolution mass spectrometry (HRGC/EI-HRMS) in determinin g the toxaphene homologue distribution. Operating parameters such as e lectron energy, trap current and source temperature were optimized in order to obtain the maximum signal of the [M-C](+) and [M-HCl](+.) fra gment ions of each homologue group. Internal interferences due to the fragment ions from the homologues with one and two additional chlorine atoms were eliminated using EI-HRMS at a resolving power of 10 000 or higher. Tandem mass spectrometry (EI-MS/MS) was used in the fragmenta tion studies. HRGC/EI-HRMS-selected ion monitoring (SIM) at a resolvin g power of 10 000 was used to determine the homologue distribution of a commercial toxaphene mixture. This technique gave detection limits o f ppb level. The performance of HRGC/EI-HRMS-SIM was compared to HRGC/ ECNI-MS using isobutane as a moderating gas. (C) 1997 by John Wiley & Sons, Ltd.