DETERMINATION OF MIREX IN FISH BY GAS-CHROMATOGRAPHY AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY COMPUTER SYSTEM

Four fish species from Lake Ontario were analyzed by various gas chromatographic and gas chromatographic-mass spectrometric-computer methods. Quantitative analyses employing reconstructed mass chromatograms with the mirex (perchloropentacyclo[5.3.0.02,6.03,9.04,8]decane or dodechlorooctahydro-1.3.4-metheno-2H-cyclobuta[c,d]pentalene) base peak (m/e 272) and gas chromatography with electron capture and Hall electrolytic detectors provided concentration values ranging from 0.15 to 0.33 µg/g fresh weight of tissue. However, the technique of selective ion monitoring or mass fragmentography using high mass ion fragments exclusively associated with mirex demonstrates that the actual mirex concentrations are from 3 to 6 times lower. Reasons for the wide range of variability as a function of methodology are discussed. © 1978, American Chemical Society. All rights reserved.