Comparison of the performance of analytical methods based on solid-phase extraction and on solid-phase microextraction for the determination of antifouling booster biocides in natural waters

Analytical procedures based on solid-phase extraction (SPE) and solid-phase microextraction (SPME) have been compared for the determination of four organic booster biocides used in marine antifouling paints (irgarol 1051, dichlofluanid, chlorothalonil, and sea-nine 211). Both techniques were coupled with gas chromatography with electron-capture, flame-thermionic, and mass-spectrometric detection. Recovery studies in spiked samples of water of different origin (distilled, lake, river, and sea water) demonstrated that Irgarol 1051, sea nine 211, and chlorothalonil were extracted efficiently (recovery > 75%) with C-18 and SDB disks whereas extraction of dichlofluanid was moderate or insufficient (less than or equal to 65%). With AC disks careful extraction procedures are needed for efficient extraction of dichlofluanid, sea-nine 211, and irgarol 1051; chlorothalonil was difficult to desorb (recovery < 60%). In SPME both fibers could be used to extract all the biocides with relatively high recoveries (65 - 118%). SPME is a more efficient multi-residue technique for the tested biocides than SPE, which requires the use of different adsorbents for determination of biocides. Very low limits of detection (0.4-20 ng L-1) can be achieved with both SPE and SPME under optimized conditions, and their potential for trace-level screening of natural waters for antifouling biocides is demonstrated. The methods were applied to the analysis of the antifouling biocides in samples of sea water from Greek marinas.