Comparison of Membrane Inlet and Capillary Introduction Miniature Mass Spectrometry for Liquid Analysis.

Quan Yu,Jinbo Zhang,Xinqiong Lu,Lili Yang,Wenyan Shi,Jianhong Zhao,Xiaohao Wang

doi:10.3390/polym11030567

Quan Yu, Jinbo Zhang + Show 5 more

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https://doi.org/10.3390/polym11030567

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Abstract

Membrane inlet mass spectrometry (MIMS) is commonly used for detecting the components in liquid samples. When a liquid sample flows through a membrane, certain analytes will permeate into the vacuum chamber of a mass spectrometer from the solution. The properties of the membrane directly determine the substances that can be detected by MIMS. A capillary introduction (CI) method we previously proposed can also be used to analyze gas and volatile organic compounds (VOCs) dissolved in liquids. When CI analysis is carried out, the sample is drawn into the mass spectrometer with no species discrimination. The performance of these two injection methods was compared in this study, and similar response time and limit of detection (LOD) can be acquired. Specifically, MIMS can provide better detection sensitivity for most inorganic gases and volatile organic compounds. In contrast, capillary introduction shows wider compatibility on analyte types and quantitative range, and it requires less sample consumption. As the two injection methods have comparable characteristics and can be coupled with a miniature mass spectrometer, factors such as cost, pollution, device size, and sample consumption should be comprehensively considered when choosing a satisfactory injection method in practical applications.

Highlights

Miniature Mass Spectrometry for Liquid AnalysisWenyan Shi 1,2, Xinqiong Lu 1,3, Jinbo Zhang 1, Jianhong Zhao 1, Lili Yang 4, Quan Yu 1, * Xiaohao Wang 1,2 * andDivision of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, State Key Laboratory of Precision Measurement Technology and Instruments, Department of PrecisionInstrument, Tsinghua University, Beijing 100084, ChinaGuangdong Province Engineering Research, Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, ChinaHebei Province Key Lab of Measurement Technology and Instrumentation, Yanshan University, Received: 26 February 2019; Accepted: March 2019; Published: March 2019 AbstractMembrane inlet mass spectrometry (MIMS) is commonly used for detecting the components in liquid samples
Was driven by a and a length of approximately 10 cm was selected as the sampling tube, and water was drawn into peristaltic pump to velocityof of4.9
membrane inlet (MI) was not uniform, the enrichment of dissolved gas in an aqueous solution in a vacuum than that of using capillary introduction (CI), and its fragment ion peak may interfere with the detection of small molecular environment was higher than that of using CI, and its fragment ion peak may interfere with the organic compounds

Summary

Introduction

Mass spectrum (MS) is an analytical method for obtaining chemical composition information by detecting the mass-to-charge ratio of charged particles. Our recent experiments have shown that liquid can be directly introduced into the mass spectrometer by using a capillary with small inner diameter (i.d.), which can effectively reduce ion interferences from the inhaled air during sampling This introduction strategy has been successfully used for VOCs detection in liquid samples [28,33] and can be extended to implement vacuum electrospray ionization in miniature ion trap device [34]. The characteristics of both the MIMS and CIMS methods for direct injection of liquid samples is systematically evaluated in this study using a miniature quadrupole mass spectrometer. It will provide a basis for the selection of injection methods to meet the needs of online real-time analysis under different conditions

Experimental Instruments and Samples

Results and Discussion

Conclusions