Lauritsen F R, Ketola R A
Physical Biochemistry Group, Institute of Biochemistry, Odense University, DK-5230 Odense M, Denmark.
Anal Chem. 1997 Dec 1;69(23):4917-22. doi: 10.1021/ac970570q.
This paper discusses the use of trap-and-release membrane inlet mass spectrometry (T&R-MIMS) for the quantitative determination of semivolatile organic compounds in real samples. We found that the T&R-MIMS technique is particular sensitive to relatively polar, semivolatile organic compounds. For example, the detection limits for the acids acetylsalicylic acid and phenoxyacetic acid were lowered by a factor of 100 as compared with those possible with standard MIMS, and caffeine was detectable only with the T&R-MIMS method. The detection limits were in the parts-per-billion range, and the dynamic range was 3 orders of magnitude. As a practical example of the application of the T&R-MIMS technique, we used it for the quantitative analysis of caffeine in ground coffee and tea leaves. Good agreement between T&R-MIMS and HPLC determinations was found, and the reproducibility of the whole analytical system for caffeine determination (extraction procedure and T&R-MIMS determination) was within 10% as relative standard deviation. However, for coffee, a large background from the essential oils prevented low-level work, such as the determination of residual caffeine in decaffeinated coffee. Obviously, the analysis of many complex matrixes will require the use of tandem mass spectrometry.
本文讨论了捕集-释放膜进样质谱法（T&R-MIMS）用于实际样品中半挥发性有机化合物的定量测定。我们发现T&R-MIMS技术对相对极性的半挥发性有机化合物特别敏感。例如，与标准MIMS相比，乙酰水杨酸和苯氧乙酸的检测限降低了100倍，咖啡因只能用T&R-MIMS方法检测到。检测限在十亿分之一范围内，动态范围为3个数量级。作为T&R-MIMS技术应用的一个实际例子，我们将其用于研磨咖啡和茶叶中咖啡因的定量分析。发现T&R-MIMS和HPLC测定结果之间具有良好的一致性，整个咖啡因测定分析系统（萃取程序和T&R-MIMS测定）的重现性以相对标准偏差计在10%以内。然而，对于咖啡，精油产生的大量背景干扰了低水平的工作，如脱咖啡因咖啡中残留咖啡因的测定。显然，对许多复杂基质的分析将需要使用串联质谱法。
