Institute of Life Science, Faculty of Medicine, Health and Life Science, Swansea University, Swansea, UK.
Waters Corp, Wilmslow, UK.
Rapid Commun Mass Spectrom. 2022 Aug 15;36(15):e9327. doi: 10.1002/rcm.9327.
Ionization by atmospheric pressure gas discharge has been employed for a long time in mass spectrometry. Inductively coupled plasma mass spectrometry is an exemplar, and widely used for elemental analysis. The technique has less uptake in organic mass spectrometry. We describe a simple source design that can be readily implemented in most atmospheric pressure ionization (API) systems and compare its performance with that of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI).
An in-house designed helium gas discharge source (referred to as 'GlowFlow') was used on a Xevo G2-S time-of-flight mass spectrometer. The GlowFlow source was transferred to a compatible Xevo TQ-S triple-quadrupole mass spectrometer using an ultrahigh-performance liquid chromatograph inlet. Its performance was compared to that of Waters ESI and APCI sources.
Preliminary results of GlowFlow on the Swansea instrument are presented to establish context and include analysis of low-molecular-mass polymers, benzoic acid and cinnamic acid. Comparison of performance on the Xevo TQ-S triple-quadrupole mass spectrometer involved three test mixtures. The method limits of detection (six-mix) for positive-ion GlowFlow source were between 0.03 and 10.00 pg with good linear response over two to four orders of magnitude and values of R > 0.98. The GlowFlow ionization source provided a signal intensity that was an order of magnitude greater than that of ESI for an atmospheric pressure gas chromatography standard mix and ionized several compounds that ESI could not.
The current GlowFlow design is relatively simple to retrofit to most API systems due to its small size. The sensitivity of the GlowFlow design is typically an order of magnitude less than that of ESI in positive-ion mode, but similar in sensitivity in negative-ion mode and comparable to that of APCI.
大气压气体放电已在质谱分析中应用了很长时间。电感耦合等离子体质谱就是一个典型的例子，并且被广泛应用于元素分析。该技术在有机质谱分析中的应用较少。我们描述了一种简单的源设计，可在大多数大气压电离（API）系统中轻松实现，并将其性能与电喷雾电离（ESI）和大气压化学电离（APCI）进行比较。
在 Xevo G2-S 飞行时间质谱仪上使用了一个内部设计的氦气放电源（称为“GlowFlow”）。GlowFlow 源通过超高效液相色谱仪进样口转移到兼容的 Xevo TQ-S 三重四极杆质谱仪上。将其性能与 Waters ESI 和 APCI 源进行了比较。
初步展示了 Swansea 仪器上的 GlowFlow 结果，以确定上下文，并包括对低分子量聚合物、苯甲酸和肉桂酸的分析。在 Xevo TQ-S 三重四极杆质谱仪上的性能比较涉及三种测试混合物。正离子 GlowFlow 源的方法检出限（六混）在 0.03 至 10.00 pg 之间，具有两个至四个数量级的良好线性响应，R 值大于 0.98。GlowFlow 电离源提供的信号强度比大气压气相色谱标准混合物的 ESI 大一个数量级，并且可以电离 ESI 无法电离的几种化合物。
由于其体积小，当前的 GlowFlow 设计相对简单，可以改装到大多数 API 系统中。在正离子模式下，GlowFlow 设计的灵敏度通常比 ESI 低一个数量级，但在负离子模式下的灵敏度相似，与 APCI 相当。
