Fr. Lauritsen et Ra. Ketola, QUANTITATIVE-DETERMINATION OF SEMIVOLATILE ORGANIC-COMPOUNDS IN SOLUTION USING TRAP-AND-RELEASE MEMBRANE INLET MASS-SPECTROMETRY, Analytical chemistry, 69(23), 1997, pp. 4917-4922
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.