DMS-MS separations with different transport gas modifiers

The current trend in analytical measurements is towards a new generation of mass spectrometry (MS) systems with enhanced sensitivity and high throughput of measurements. At the same time, increasing the sensitivity of MS can augment potential problems with isobaric interferences, which can reveal the undesirable effect of chemical noise on quality of analysis, particularly for quantitative measurements. Therefore, fast and effective methods of sample pretreatment which help to reduce the sample complexity are needed. Over the past decade it has been established that differential mobility spectrometry (DMS) can be employed as an effective pre-separation technique for atmospheric pressure ionization MS. DMS ion pre-filtering can improve simultaneously two vital parameters for mass spectrometry; signal to noise ratio and selectivity of MS measurement. In addition it was found that adding the appropriate amount of chemical modifiers to the transport gas can substantially enhance the resolving power of DMS. This valuable finding was immediately accepted and currently is exploited in commercial DMS-MS systems. The goal of this paper is to expand the understanding and systematization of the current knowledge related to augmentation of the separation power of DMS by adding chemical modifiers into the gas stream. This manuscript, reports systematic experimental data for a 140 chemicals mixture, measured within a DMS cell in the presence and absence of chemical modifiers. These data help to map out the behavior of chemical entities for different compositions of transport gases, including nitrogen, nitrogen/helium mixtures, and nitrogen with the addition of various polar and non-polar modifiers.