Determination of organic UV filters in water by stir bar sorptive extraction and direct analysis in real-time mass spectrometry

Authors: Manuela Haunschmidt, Christian W. Klampfl, Wolfgang Buchberger, Robert Hertsens
2011, Jul, 23, ,


Analytical and Bioanalytical Chemistry, 2010.

A screening method for analyzing environmental waters contaminated
with UV filters using direct analysis in real-time mass spectrometry
(DART®-MS) was developed. To demonstrate the suitability of DART®-MS a
test set of seven organic UV filters, namely benzophenone-3 (BP-3),
ethylhexyl dimethyl p-aminobenzoate (OD-PABA), 4-t-butyl-4'-
methoxydibenzoylmethane (BM-DBM), homomethyl salicylate (HMS), 2-
(ethylhexyl) salicylate (EHS), octocrylene (OC), and 4-
methylbenzylidene camphor (4-MBC), was defined. In the first step,
standard solutions of the analytes prepared in methanol were
investigated in order to determine optimum parameters for the DART®-MS.
Because of the very low concentrations of UV filters expected in
environmental water samples, a pre-concentration step using stir bar
sorptive extraction was performed. DART®-MS allows the direct, simple
and rapid semi-quantitative analysis of the analytes enriched on the
surface of the polydimethylsiloxane-coated stir bars. The optimized
method provided calibration curves with correlation coefficients
R>0.959, repeatability from 5% (for 4-MBC) to 30% (for BM-DBM)
relative standard deviation and limits of detection lower than 40 ng L
-1 for all analytes. Finally, real lake water samples from locations
with typical leisure activities were analyzed. Results obtained with
the developed DART®-MS method were cross-checked by confirmatory
analysis using thermodesorption gas chromatography mass spectrometry
(TD-GC-MS). Thereby, it could be demonstrated that both analytical
methods provide comparable concentrations for the UV filters in the
lake water samples.
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