Novel design for drift tubes in ion mobility spectrometry for optimised resolution of peak clusters

Abstract

In the past decade, Ion Mobility Spectrometry has established a very strong foot hold in medical and biological applications due to its numerous advantages including sensitivity, ruggedness and reproducibility. During the analysis of complex samples such as human breath, it is very probable that two or more analytes form peak clusters due to similar drift times and pre-separation times, thus hindering the identification of the analytes. Furthermore, such overlapping of signal makes quantification very difficult or even impossible. Resolving these peak clusters is important to enable proper identification and quantification of analytes detected for diagnosis. Hence, we designed a drift tube with variable length for investigating the influence of varying drift lengths and electric field on resolution. Peak cluster formations usually seen between acetone and the reactant ion peak, between the dimer peaks of 2-Heptanone and 4-Heptanone have been resolved with the new drift tube after optimisation. These novel drift tubes could easily negate the peak clusters often encountered when complex medical and biological samples are measured with the ion mobility spectrometer. Furthermore, the fact that these drift tubes can be altered in length thereby providing a wide range of electric fields (from 50 to 3300 V.cm −1 ), opens up new research options in ion motions in an electric field.

Volatile Organic Compounds in Uremia

“…preseparation temperature, field strength, drift gas and carrier gas flow, preseparation and drift length – and a larger population of patients with renal failure will allow a more distinct separation of analytes that are now displayed very close to one another. Hariharan et al recently demonstrated the potential of optimizing experimental parameters with regard to peak resolution [20] . Moreover, TD-GC/MS was not able to identify two analytes, potentially due to the low number of patients and low concentrations in the breath.…”

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“…где (20) Умножив (14) на (20), получаем: В статье рассматриваются универсальные системы на основе элементарных функций, позволяющие проводить аппроксимацию импульсных сигналов различного вида и длительности и обеспечивать их простое математическое описание. Предложены степенные, многочленно-косинусоидальные, экспоненциально-многочленные, дробно-рациональные, B-сплайновые системы сигналов, а также системы сигналов с ограниченным спектром.…”

Bradbury-Nielsen vs. Field switching shutters for high resolution drift tube ion mobility spectrometers

“…From these equations, two possible ways of constructing high resolution drift tube IMS while maintaining the 34 excellent limits of detection become apparent. First, longer drift tubes improve separation power [7] since 35 resolution grows proportional to ⁄ , while the effects of the drift length on the signal-to-noise-ratio equation (2), this will maintain a constant SNR, as it only depends on the match between and , while 1 the resolution increases accordingly to equation (1). Thus, it is possible in theory to reach extremely high 2 resolutions in a compact drift tube IMS without sacrificing the excellent limits of detection.…”