Differential mobility spectrometers (DMS) can be employed as a selective ion detector as well as an effective ion species pre-separation technique for atmospheric pressure ionization mass spectrometry (API MS).  In the second case the DMS ion pre-filtering can improve two vital for MS parameters; signal to noise ratio and selectivity of MS measurement.  In addition, over the past decade it was well documented that adding the appropriate amount of chemical modifiers to the transport gas can substantially enhance the resolving power of DMS separation. This valuable finding was instantly accepted and currently is exploited in commercial stand alone DMS and  DMS-MS systems. The goal of  this   presentation  is to expand the understanding and systematization of the current knowledge  related to augmentation of the separation power of DMS, by adding vapors of different chemicals  into the transport gas. This presentation includes systematic experimental data for analysis of complex mixtures with different compositions of transport gases including nitrogen, and nitrogen with the addition of various polar and non-polar modifiers. In addition, a new method for comparison of the orthogonality of separations for different classes of chemical modifiers (metric for determine level of modifiers orthogonality) was developed and is presented.

Investigation of the chemical orthogonality effect of transport gas modifiers on DMS separations

246th National Meeting (2013)

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