Comparison of negative and positive modes of ion-mobility increment spectrometry in the detection of heroin vapors

Some analytical characteristics of ion-mobility increment spectrometry (IMIS) in the negative and positive modes were compared in detecting diacetylmorphine vapors. It was shown experimentally that the sensitivity of IMIS in the negative mode to diacetylmorphine depends on the concentration of the water vapors in the drift gas: the lower the concentration, the higher the sensitivity. Data for cocaine are presented for comparison. Sampling diacetylmorphine and cocaine in the ionization chamber of the ion-mobility increment spectrometer was performed using a chromatograph with a multicapillary gas-chromatographic column.