Enhancing Performance of Ion Mobility Spectrometry Based on a Dual Effect Tyndall-Powell Gate Controlling Method
Ion mobility spectroscopy(IMS)has many advantages such as fast detection speed,high sensitivity,and portability,and thus plays an important role in on-site detection of chemical agents,explosives,drugs,environmental pollutants,and other pollutants.As a key component of IMS,the ion number density and temporal width of the injected ion packets directly determine the IMS detection sensitivity and resolution.In yhis study,the dual-parallel-grid structure of Tyndall-Powell gate(TPG),which could effectively isolate the electric fields within the ionization region,gate region,and drift region,was utilized to develop a dual effect TPG gating method for simultaneously enhancing the mobility discrimination reduction and ion packet temporal width compression,thereby improving the IMS performance.A TPG-IMS platform was thus built up and the effects of parameters such as gate opening pulsed width,gate penetration voltage,and ion injection voltage on the sensitivity and resolving power of IMS were systematically investigated using the dual-effect TPG gating method.The results demonstrated that,when detecting diethyl phosphate(DEP)and diethyl methylphosphate(DEMP)mixture using the dual effect TPG gating method,the peak currents of(DEP)2H+and(DEP·DEMP)H+ions with low K0 values were increased by 18 and 45 times respectively,while maintaining a high resolution of about 90.The limits of detection for DEP and DEMP were decreased from 4 ppb(10-9)to 235 ppt(10-12)and from 5 ppb to 156 ppt,respectively.This gating method only regulated the potential of the TPG grid adjacent to the drift region,without changing the structure of the ion mobility tube,making it convenient to apply on existing commercial instruments.
Ion mobility spectrometryParallel dual-grid ion gateMobility discriminationTemporal compressionComprehensive gating performance
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