Detection limits of an ion mobility detector after capillary gas chromatography

A method for setting gating parameters is presented that maximizes response in ion mobility detection following capillary gas chromatography. The method requires knowledge of the drift times of the product ion or ions of interest and the drift times of the reactant ions. These values are obtainable from ion mobility spectra captured after capillary gas chromatography. The capillary insertion distance into the ion source and the presence or absence of an aperture grid were also found to have considerable effect on chromatographic response. Under optimized conditions, minimum detectable limits of <1 fmol/s are reported for tributylamine, phenyl sulfide, and tributyl phosphate. These values demonstrate significant improvements over reported detection limits of organics by the flame ionization detector and sulfur‐containing species by the flame photometric detector. The values show slight improvement over those reported for detection of nitrogen and are comparable to those reported for detection of phosphorus‐containing species by the thermionization detector.