Quantitative Determination of Semivolatile Organic Compounds in Solution Using Trap-and-Release Membrane Inlet Mass Spectrometry

• Published in: Analytical chemistry (Washington) 1997-12, Vol.69 (23), p.4917-4922
• Main Authors: Lauritsen, Frants R, Ketola, Raimo A
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Membranes; Scientific imaging; Spectrometric and optical methods; VOCs; Volatile organic compounds
• ISSN: 0003-2700; 1520-6882
• 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.