Optimization of solid-phase microextraction for the gas chromatographic-mass spectrometric determination of synthetic musk fragrances in water samples

Described is a solid-phase microextraction-gas chromatography-mass spectrom etric procedure for the determination of three polycyclic musk fragrances ( galaxolide, tonalide, celestolide) and a nitro musk fragrance (musk ketone) in natural river water. Both classes of the musk fragrances could be extra cted reproducibly from water samples with a recovery in the range of 45-50% and relative standard deviation of 11-18% for fragrances at 25-260 ng/l le vels. Detection limits were between 14 and 22 ng/l. To achieve this reprodu cibility it was necessary to use an internal standard, pentachloronitrobenz ene, for all substances. Best recoveries were achieved with polydimethylsil oxane (PDMS)-divinylbenzene fibers (compared to recoveries obtained with PD MS, polyacrylate or carboxen fibers) and extraction times of 45 min at 30 d egreesC, with no need for attainment of equilibrium conditions. The latter was achieved at about 2 h. For Elbe River water, in the vicinity of Magdebu rg, no matrix effects were observed. While the average levels of celestolid e and musk ketone for samples investigated were below the detection limits, 14 and 22 ng/l, respectively, and for tonalide below the limit of quantifi cation, 22 ng/l, the ambient levels of galaxolide in the Elbe River were 11 7 ng/l. (C) 2000 Elsevier Science BN. All rights reserved.