Introduction An IMS method for determining trace quantities of Dobers Chematic ® 91AE detergent (an acidic detergent) has been developed using the IONSCAN-LS. The method is based on the detection of the surfactant LAE (linear alcohol ethoxylate), a material also found in other Dober detergents such as the basic Chematic 82AE and the neutral Chematic 99AE and variations of this method can readily be developed to analyze for those detergents.