University of Duisburg-Essen, Applied Analytical Chemistry, Universitaetsstr. 5, 45141 Essen, Germany.
Molecules. 2020 Jul 16;25(14):3253. doi: 10.3390/molecules25143253.
A closed atmospheric pressure chemical ionization (APCI) ion source as interface between a gas chromatograph (GC) and a triple quadrupole mass spectrometer (QqQ-MS) was developed. The influence of different ion source conditions, such as humidity, make-up gas flow, and the position of the GC column, were investigated and determined as main factors to increase sensitivity and repeatability of the system. For a performance test under real conditions, the new APCI ion source was used for the determination of plant protection products in commercially available coffee beans from Vietnam. The ionization behavior was investigated and the majority of the analytes were detected as [MH], [M], or as characteristic fragment ions, which have been assigned to ion source fragmentation. The developed GC-MS methods are based on tandem MS (MS/MS) and revealed for the plant protection products limits of detection (LOD) between 1 and 250 pg on column and relative standard derivations for all compounds < 16%. The used ultrasonic solid-liquid extraction yielded recovery rates of approximately 60 to 100%. Residues of herbicide methyl esters, organophosphorus compounds, and organonitrogen compounds have been detected in the analyzed coffee beans.
我们开发了一种封闭的大气压化学电离（APCI）离子源，作为气相色谱仪（GC）和三重四极杆质谱仪（QqQ-MS）之间的接口。研究了不同的离子源条件，如湿度、补充气流和 GC 柱的位置，它们是提高系统灵敏度和重复性的主要因素。为了在实际条件下进行性能测试，我们将新的 APCI 离子源用于检测来自越南的市售咖啡豆中的植物保护产品。研究了这些化合物的电离行为，大多数分析物被检测为 [MH]、[M] 或特征碎片离子，这些离子已被分配到离子源的碎裂过程中。所开发的 GC-MS 方法基于串联质谱（MS/MS），对于这些植物保护产品，在柱上的检测限（LOD）在 1 至 250 pg 之间，所有化合物的相对标准偏差均小于 16%。所使用的超声固相萃取得到的回收率约为 60%至 100%。在所分析的咖啡豆中检测到了除草剂甲酯、有机磷化合物和有机氮化合物的残留。
