Online coupling of microchip electrophoresis with ion mobility spectrometry for direct analysis of complex liquid samples

芯片電泳與離子遷移譜在線耦合，可直接分析復雜的液體樣品

Marián Masár^a,? , Jasna Hradski^a , Michaela Nováková^a , Roman Szucs^a , Martin Sabo^b , Štefan Matej?ík^b

^a Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH2, Ilkovi?ova 6, 842 15, Bratislava, Slovakia

^b Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F2, 842 48, Bratislava, Slovakia

ABSTRACT

This is the first report of coupling of microchip electrophoresis (MCE) with ion mobility spectrometry (IMS) for the analysis of liquid samples. Zone electrophoresis, employed on a microchip as a MCE technique, is suitable for coupling with IMS. Sample components separated electrophoretically in liquid phase were transferred from the microchip using auxiliary liquid. Direct liquid sampling interface was used for sample evaporation and introduction to IMS. In the IMS analyzer, the sample components were further separated in the gaseous phase. Online MCE-IMS coupling enabled acquisition of characteristic IMS response for the individual analytes. The proposed MCE-IMS technique was tested on a model mixture of a homologous series of carboxylic acids (formic acid, acetic acid, propionic acid, butyric acid, valeric acid and hexanoic acid) and subsequently applied to the analysis of wastewater sample obtained from a cattle farm. Total analysis time did not exceed six minutes regardless of the sample. Reproducibility of peak width in the MCE ranged from 0.56 to 1.95% RSD, while reproducibility of time of IMS response was in the range of 2.52–5.44% RSD for the studied carboxylic acids. RSD values of their reduced ion mobility were less than 0.56% for model and wastewater sample. Limits of detection ranged from 0.07 to 2.61 mg L−1 . The results clearly show the great analytical potential of developed MCE-IMS coupling for the analysis of complex liquid samples.

這是微芯片電泳(MCE)與離子遷移譜(IMS)耦合用于液體樣品分析的份報告。在微芯片上用作MCE技術的區域電泳適用于與IMS耦合。使用輔助液體，將通過電泳分離成液相的樣品組分從微芯片中轉移出來。直接液體采樣接口用于樣品蒸發和引入IMS。在IMS分析儀中，樣品組分在氣相中進一步分離。在線MCE-IMS耦合可獲取單個分析物的特征IMS響應。擬議的MCE-IMS技術在一系列羧酸的同源混合物(甲酸，乙酸，丙酸，丁酸，戊酸和己酸)，隨后用于分析從養牛場獲得的廢水樣品。無論樣品如何，總分析時間均不超過六分鐘。對于所研究的羧酸，MCE中峰寬的重現性介于0.56至1.95%RSD之間，而IMS響應時間的重現性介于2.52%至5.44%RSD之間。對于模型和廢水樣品，其降低的離子遷移率的RSD值小于0.56%。檢測限范圍為0.07至2.61 mg L 研究的羧酸的RSD為44%。對于模型和廢水樣品，其降低的離子遷移率的RSD值小于0.56%。檢測限范圍為0.07至2.61 mg L 研究的羧酸的RSD為44%。對于模型和廢水樣品，其降低的離子遷移率的RSD值小于0.56%。檢測限范圍為0.07至2.61 mg L-1。結果清楚地表明，開發的MCE-IMS偶聯劑對復雜液體樣品的分析具有巨大的分析潛力。