QUANTITATIVE-DETERMINATION OF SEMIVOLATILE ORGANIC-COMPOUNDS IN SOLUTION USING TRAP-AND-RELEASE MEMBRANE INLET MASS-SPECTROMETRY

This paper discusses the use of trap-and-release membrane inlet mass s pectrometry (T&R-MIMS) for the quantitative determination of semivolat ile organic compounds in real samples. We found that the T&R-MIMS tech nique is particular sensitive to relatively polar, semivolatile organi c compounds, For example, the detection limits for the acids acetylsal icylic acid and phenoxyacetic acid were lowered by a factor of 100 as compared with those possible with standard MIMS, and caffeine was dete ctable 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 magnit ude, As a practical example of the application of the T&R-MIMS techniq ue, we used it for the quantitative analysis of caffeine in ground cof fee and tea leaves. Good agreement between T&R-MIMS and HPLC determina tions was found, and the reproducibility of the whole analytical syste m for caffeine determination (extraction procedure and T&R-MIMS determ ination) was within 10% as relative standard deviation. However, for c offee, 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.