Novel applications of highly sensitive liquid chromatography/mass spectrometry/mass spectrometry for the direct detection of ultra-trace levels of contaminants in water.

Recent advances in the sensitivity of liquid chromatography/mass spectrometry (LC/MS) instrument technology provide the basis for the direct detection, i.e. without sample pre-concentration, of organic contaminants in water in the ng/L range. Novel applications for the analysis of atrazine and some of its desalkylated and hydroxylated degradation products, the pharmaceutical compounds diclofenac and carbamazepine, sulfonylurea herbicides, and iodinated X-ray contrast media have been developed. For each analyte a specific tandem mass spectrometric (MS/MS) transition has been selected and the corresponding mass spectrometric parameters optimised. All analytes could be analysed within three specific analytical runs including different high-performance liquid chromatography (HPLC) conditions. Detection limits were determined to be better than 10 ng/L for the direct analysis of the compounds in water except for X-ray contrast media, for which detection limits were found to be up to one order of magnitude higher. The methods have been successfully utilised for the analysis of natural waters. Matrix effects frequently occurring in LC/MS have shown to be low to moderate in the case of X-ray contrast media. This work demonstrates that for the analysis of a large number of water contaminants, the sample pre-concentration step could possibly be omitted.