Quantitative Aspects to Response

IMSs perform successfully in several applications where only threshold response is necessary or important, and examples include the detection of explosives and 

FIGURE 8.9 Selectivity induced by cation adduction. Ion mobility separation of methyl-p-D-galactopyranoside from its isomer methyl-a-D-galactopyranoside using different cation adducts. (From Dwivedi et al., Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS), J. Am. Soc. Mass Spectrom. 2007, 18, 1163-1175. With permission.) 

These are seen with advances in the detection of explosives with handheld analyzers as well as with fixed or stationary analyzers. Parallel advances have occurred with instrumentation and procedures requiring quantitative determinations. These have occurred with the availability of improved drift tubes that exhibit fast response, low memory effects, and reproducible delivery of sample to the ion source. Together, these have resulted in improved precision, sensitivity, and linear range compared to previous generations of analyzers. In the following sections, the principles underlying quantitative behavior for IMS analyzers are discussed. 

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