A method has been developed for the trace analysis of 27 compounds from a diverse group of pharmaceuticals, steroids, pesticides, and personal care products. The method employs solid-phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC/MS/ MS), using electrospray ionization (ESI) in both positive and negative modes and atmospheric pressure chemical ionization in positive mode. Unlike many previous methods, a single SPE procedure using 1 L of water coupled to a simple LC method is used for all ionization modes. Instrument detection limits for most compounds were below 1.0 pg on column with reporting limits of 1.0 ng/L in water. Recoveries for most compounds in deionized water were greater than 80%. Sulfuric acid was found to be the preferred sample preservative, and structures of all MS/MS product ions are proposed. Matrix effects from waters with a high content of treated municipal effluent were observed in both ESI modes and are discussed in the paper.In recent years, reports have shown that certain contaminants at trace concentrations in surface waters can have dramatic effects on the endocrine systems of aquatic organisms. 1-3 These compounds are collectively known as endocrine-disrupting compounds (EDCs). Pharmaceuticals, steroids, and personal care products have also been detected in the aquatic environment and may act as EDCs. [4][5][6] As environmental contaminants continue to be discovered, the need for comprehensive methods for their sensitive and selective identification has also increased. Traditional gas chromatography is of limited value without time-consuming and labor-intensive derivatization because many environmental contaminants are polar, have low volatility, and are thermally labile. This has led to the increased use of liquid chromatography/mass spectrometry (LC/MS) due to its ability to effectively analyze these types of molecules.LC/MS methods for the analysis of pharmaceuticals, steroids, and personal care products in water have been developed for a number of different mass spectrometers using diverse extraction procedures and elution protocols. A complete review of methods for the analysis of these compounds in water using LC/MS is beyond the scope of this paper, and thorough reviews have previously been published. [7][8][9] The majority of concentration techniques involve solid-phase extraction (SPE) in which many solid phases, eluent schemes, and final solvents with and without ionpairing reagents, buffers, and modifiers were used. 10-20 Additionally, both single quadrupole 11,15,16

The oxidative removal of a diverse group of trace organic contaminants from surface water and wastewater was evaluated using ozone (O 3 ) and O 3 combined with hydrogen peroxide (O 3 /H 2 O 2 ). Target compounds included estrogenic and androgenic steroids, pharmaceuticals, pesticides, and industrial chemicals. Bench-and pilot-scale experiments were conducted with surface water spiked with the target compounds and wastewater effluent containing ambient concentrations of target compounds. Full-scale water treatment plants were sampled before and after ozonation to determine if bench-and pilot-scale results accurately predict full-scale removal. In both drinking water and wastewater experiments, the majority of target compounds were removed by greater than 90% at O 3 exposures commonly used for disinfection. Atrazine, iopromide, meprobamate, and tris-chloroethylphosphate (TCEP) were the most recalcitrant compounds to oxidize using O 3 , with removals generally less than 50%. The addition of H 2 O 2 for advanced oxidation was of little benefit for contaminant removal as compared to O 3 alone. O 3 /H 2 O 2 provided a marginal increase in the removal of dilantin, diazepam, DEET, iopromide, and meprobamate, while decreasing the removal efficacy of pentoxifylline, caffeine, testosterone, progesterone, and androstenedione. In wastewater experiments, O 3 and O 3 /H 2 O 2 were shown to remove in vitro estrogenicity. Collectively, these data provide evidence that O 3 is a highly effective oxidant for removing the majority of trace organic contaminants from water.

A simple and rapid method has been developed to simultaneously measure sub-µg/L quantities of the oxyhalide anions bromate, chlorate, iodate, and perchlorate in water samples. Water samples (10 mL) are passed through barium and hydronium cartridges to remove sulfate and carbonate, respectively. The method utilizes the direct injection of 10 µL volumes of water samples into a liquid chromatography-tandem triple-quadrupole mass spectrometry (LC-MS/MS) system. Ionization is accomplished using electrospray ionization in negative mode. The method detection limits were 0.021 µg/L for perchlorate, 0.045 µg/L for bromate, 0.070 µg/L for iodate, and 0.045 µg/L for chlorate anions in water. The LC-MS/MS method described here was compared to established EPA methods 300.1 and 317.1 for bromate analysis and EPA method 314.0 for perchlorate analysis. Samples collected from sites with known contamination were split and sent to certified laboratories utilizing EPA methods for bromate and perchlorate analysis. At concentrations above the reporting limits for EPA methods, the method described here was always within 20% of the established methods, and generally within 10%. Twenty-one commercially available bottled waters were analyzed for oxyhalides. The majority of bottled waters contained detectable levels of oxyhalides, with perchlorate e0.74 µg/L, bromate e76 µg/L, iodate e25 µg/ L, and chlorate e5.8 µg/L. Perchlorate, iodate, and chlorate were detectable in nearly all natural waters tested, while bromate was only detected in treated waters. Perchlorate was found in several rivers and reservoirs where it was not found previously using EPA 314.0 (reporting limit of 4 µg/L). This method was also applied to common detergents used for cleaning laboratory glassware and equipment to evaluate the potential for sample contamination. Only chlorate appeared as a major oxyhalide in the detergents evaluated, with concentrations up to 517 µg/g. Drinking water treatment plants were also evaluated using this method. Significant formations of chlorate and bromate are demonstrated from hypochlorite generation and ozonation. From the limited data set provided here, it appears that perchlorate is a ubiquitous contaminant of natural waters at trace levels.

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