Abstract

The detection limit is one of the most important performance characteristics for portable mass spectrometers (MS). To significantly reduce the size and the weight, small vacuum pumps are used in portable MS which leads to the use of a discontinuous atmospheric pressure interface (DAPI). Multiple ion injections (M-DAPI), which accumulates ions through opening the DAPI pinch valve several times during the ion injection period while maintaining a radio frequency (RF) voltage continuously on the trap, was shown to improve the sensitivity of DAPI-based portable MS. A systematic investigation of the optimization of M-DAPI was performed. The primary parameters affecting the performance of M-DAPI were optimized and sensitivity and stability improvements are reported. An 11.6-fold improvement in sensitivity was achieved by M-DAPI compared to the single ion injection DAPI operation for 1 μg/mL enrofloxacin. A more than 10-fold reduction in the limit of detection (LOD) to 0.01 μg/mL was also obtained. In addition, the stability was improved by M-DAPI with a relative standard deviation of 14.4% compared to 4.6% for DAPI.

摘要

检测限是便携式质谱仪 (MS) 最重要的性能特征之一。为了显着减小尺寸和重量，便携式 MS 中使用了小型真空泵，这导致使用不连续大气压接口 (DAPI)。多次离子注入 (M-DAPI)，在离子注入期间通过多次打开 DAPI 夹管阀来积累离子，同时在阱上持续保持射频 (RF) 电压，被证明可以提高基于 DAPI 的便携式设备的灵敏度多发性硬化症。对 M-DAPI 的优化进行了系统研究。优化了影响 M-DAPI 性能的主要参数，并报告了灵敏度和稳定性的改进。一个 11。与 1 μg/mL 恩诺沙星的单次离子注入 DAPI 操作相比，M-DAPI 的灵敏度提高了 6 倍。检测限 (LOD) 也降低了 10 倍以上，降至 0.01 μg/mL。此外，M-DAPI 提高了稳定性，相对标准偏差为 14.4%，而 DAPI 为 4.6%。