Miniature radio-frequency mobility analyzer as a gas chromatographic detector for oxygen-containing volatile organic compounds, pheromones and other insect attractants

A high electric field, radio-frequency ion mobility spectrometry (RF-IMS) a nalyzer was used as a small detector in gas chromatographic separations of mixtures of volatile organic compounds including alcohols, aldehydes, ester s, ethers, pheromones, and other chemical attractants for insects. The dete ctor was equipped with a 2 mCi Ni-63 ion source and the drift region for io n characterization was 5 mm wide, 15 mm long and 0.5 mm high. The rate of s canning for the compensation voltages was 60 V s(-1) and permitted four to six scans to be obtained across a capillary chromatographic elution profile for each component. The RF-IMS scans were characteristic of a compound and provided a second dimension of chemical identity to chromatographic retent ion adding specificity in instances of co-elution. Limits of detection were 1.6-55X10(-11) g with an average detection limit for all chemicals of 9.4X 10(-11) g. Response to mass was linear from 2-50X10(-10) g with an average sensitivity of 4 pA ng(-1). Separations of pheromones and chemical attracta nts for insects illustrated the distinct patterns obtained from gas chromat ography with RF-IMS scans in real time and suggest an analytical utility of the RF-IMS as a small, advanced detector for on-site gas chromatographs. ( C) 2001 Elsevier Science B.V All rights reserved.