常压热解离化学电离源的研制及表征

Development of Thermal Dissociation Atmospheric Chemical Ionization Source for Rapid Mass Spectrometric Analysis of Ambient Samples

自行研制了常压热解离化学电离源(TDCI),与商品化LTQ XL质谱仪成功联用,进一步考察了TDCI的性能,并对其应用领域进行了初步探索。TDCI-MS/MS谱图表明,离子液体可在现有实验条件下产生特征离子碎片;升高TDCI源偏置电压和温度,可以提高离子液体的信号强度。基于优化后的实验参数,常压热解离化学电离质谱方法(TDCI-MS)可以有效检测沙丁胺醇和萘等极性与非极性物质。本方法无需对样品进行预处理,单个样品测定时间少于30 s,相对标准偏差(RSD)为5.9%～11.1%,测得的极性或非极性物质的检出限均低于2.9×10-7 g/L。TDCI-MS方法快速、简便,且易于同小型质谱结合用于现场检测,为常压快速质谱检测方法的应用提供了新思路。

A novel thermal dissociation atmospheric chemical ionization source（TDCI） was developed for rapid chemical ionization of ambient analytes in complex matrices.By coupling the TDCI source to a commercial LTQ XL mass spectrometer,the dissociation of chemical reagents such as ionic liquids was systematically investigated using multiple-stage mass spectrometric experiments.The primary ions generated through the thermal dissociation process of the ionic liquids were accelerated by the high voltage applied on the repelling electrode of the TDCI source,and then reacted with the analytes present in the matrices of the raw samples to produce ions of analytes,which were then guided to the LTQ instrument for mass analysis.The construction of the TDCI source was detailed in the text.The effects of the experimental parameters such as the pyrolysis temperature,the distance,and the angles formed between the electrodes were experimentally studied using the signals of characteristic fragments of the ionic liquid.Under the optimal experimental parameters,TDCI was able to directly ionize a wide variety of compounds,including the poplar（e.g.,amino acids,doping compounds） and non-polar chemicals（e.g,naphthalene） for sensitive detection using LTQ-MS,without any sample pretreatment.The average time for a single sample analysis was less than 30 s,and the relative standard deviation of the method was in the range of 5.9%-11.1%;the LOD for naphthalene was estimated to be 2.93×10^-7 g/L.