Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V, Otto-Hahn-Str. 6b, 44227, Dortmund, Germany.
Rapid Commun Mass Spectrom. 2013 Feb 15;27(3):419-29. doi: 10.1002/rcm.6469.
The present study reports on the evaluation of dielectric barrier discharge microplasma ionization (DBDI) for liquid chromatography/high resolution mass spectrometry (LC/HRMS) analyses of pesticide residues in fruit and vegetables. Ionization, fragmentation, analytical performance and matrix effects displayed by LC/DBDI-MS were critically evaluated and compared with both atmospheric pressure chemical ionization (APCI) and electrospray (ESI), using a set of over 40 representative multiclass pesticides.
Sample preparation was accomplished using standard QuEChERS procedure and the identification and quantitation of the pesticides tested accomplished by means of LC/MS with a hybrid linear quadrupole ion trap (LIT)-Fourier transform ion cyclotron resonance (FTICR) mass spectrometer operated in full-scan positive ion mode using DBDI, APCI and ESI sources.
The developed LC/DBDI-MS method allowed the screening of 43 pesticides in three different vegetable matrices: apple, orange and tomato. Minor matrix effects (i.e. signal suppression or enhancement ≤20%) were observed in most of the studied compounds: 95%, 70% and 81% of the studied compounds showed minor matrix effects in extracts of apple, orange and tomato, respectively. The results of the analysis of spiked orange extracts showed that the sensitivity obtained with LC/DBDI-MS is appropriate for multi-residue analysis of pesticide residues in fruit and vegetable samples. The limits of quantitation (LOQs) obtained for most of the studied pesticides were in compliance with the European Regulation 396/2005 (and subsequent updates) on food commodities (default maximum residue level of 10 µg kg(-1)).
Comparative studies with commercial sources demonstrate the suitability of DBDI as an ionization technique for residue analysis, because of the combination of the following two advantages: (1) the use of DBDI provides minimized matrix effects compared with APCI, and (2) improved the detection - in terms of sensitivity - of selected compounds that are not easily ionized by ESI, such as parathion.
本研究报告评估了介电阻挡放电微等离子体电离（DBDI）在果蔬中农药残留的液相色谱/高分辨质谱（LC/HRMS）分析中的应用。通过使用一套超过 40 种代表性多类农药，对 LC/DBDI-MS 的电离、碎裂、分析性能和基质效应进行了严格评估，并与大气压化学电离（APCI）和电喷雾（ESI）进行了比较。
采用标准 QuEChERS 法进行样品前处理，采用液相色谱/质谱联用技术，使用混合线性四极离子阱（LIT）-傅里叶变换离子回旋共振（FTICR）质谱仪，在全扫描正离子模式下，采用 DBDI、APCI 和 ESI 源，对所测试的农药进行鉴定和定量。
建立的 LC/DBDI-MS 方法可用于三种不同蔬菜基质（苹果、橙子和西红柿）中 43 种农药的筛查。在所研究的大多数化合物中，观察到较小的基质效应（即信号抑制或增强≤20%）：在所研究的化合物中，95%、70%和 81%的化合物在苹果、橙子和西红柿提取物中表现出较小的基质效应。对添加橙子提取物的分析结果表明，LC/DBDI-MS 获得的灵敏度适用于水果和蔬菜样品中农药残留的多残留分析。对于大多数研究的农药，LOQs 均符合欧洲法规 396/2005（及其后续更新）中关于食品的规定（默认最大残留限量为 10 µg kg(-1)）。
与商业来源的比较研究表明，DBDI 作为一种离子化技术适用于残留分析，因为它结合了以下两个优点：（1）与 APCI 相比，DBDI 的使用可最大限度地减少基质效应；（2）改善了对某些化合物的检测灵敏度-这些化合物不易通过 ESI 离子化，例如对硫磷。
