The occurrence of UV filters in natural and drinking water in São Paulo State (Brazil).

Ultraviolet (UV) filters are widely used in the formulation of personal care products (PCPs) to prevent damage to the skin, lips, and hair caused by excessive UV radiation. Therefore, large amounts of these substances are released daily into the aquatic environment through either recreational activities or the release of domestic sewage. The concern regarding the presence of such substances in the environment and the exposure of aquatic organisms is based on their potential for bioaccumulation and their potential as endocrine disruptors. Although there are several reports regarding the occurrence and fate of UV filters in the aquatic environment, these compounds are still overlooked in tropical areas. In this study, we investigated the occurrence of the organic UV filters benzophenone-3 (BP-3), ethylhexyl salicylate (ES), ethylhexyl methoxycinnamate (EHMC), and octocrylene (OC) in six water treatment plants in various cities in Southeast Brazil over a period of 6 months to 1 year. All of the UV filters studied were detected at some time during the sampling period; however, only EHMC and BP-3 were found in quantifiable concentrations, ranging from 55 to 101 and 18 to 115 ng L(-1), respectively. Seasonal variation of BP-3 was most clearly noticed in the water treatment plant in Araraquara, São Paulo, where sampling was performed for 12 months. BP-3 was not quantifiable in winter but was quantifiable in summer. The levels of BP-3 were in the same range in raw, treated and chlorinated water, indicating that the compound was not removed by the water treatment process.

Determination of estrogenic mycotoxins in environmental water samples by low-toxicity dispersive liquid-liquid microextraction and liquid chromatography-tandem mass spectrometry.

A novel, simple, rapid and eco-friendly method based on dispersive liquid-liquid microextraction using a bromosolvent was developed to determine six estrogenic mycotoxins (zearalenone, zearalanone, α-zearalanol, ß-zearalanol, α-zearalenol and ß-zearalenol) in water samples by liquid chromatography-electrospray ionization tandem mass spectrometry in the negative mode (LC-ESI-MS/MS). The optimal conditions for this method include the use of 100 µL bromocyclohexane as an extraction solvent (using a non-dispersion solvent), 10 mL of aqueous sample (adjusted to pH 4), a vortex extraction time of 2 min, centrifugation for 10 min at 3500 rpm and no ionic strength adjustment. The calibration function was linear and was verified by applying the Mandel fitting test with a 95% confidence level. No matrix effect was observed. According to the relative standard deviations (RSDs), the precision was better than 13% for the repeatability and intermediate precision. The average recoveries of the spiked compounds ranged from 81 to 118%. The method limits of detection (LOD) and quantification (LOQ) considering a 125-fold pre-concentration step were 4-20 and 8-40 ng L(-1), respectively. Next, the method was applied to the analysis of the environmental aqueous samples, demonstrating the presence of ß-zearalanol and zearalanone in the river water samples.

Method validation using weighted linear regression models for quantification of UV filters in water samples.

This paper describes the validation of a method consisting of solid-phase extraction followed by gas chromatography-tandem mass spectrometry for the analysis of the ultraviolet (UV) filters benzophenone-3, ethylhexyl salicylate, ethylhexyl methoxycinnamate and octocrylene. The method validation criteria included evaluation of selectivity, analytical curve, trueness, precision, limits of detection and limits of quantification. The non-weighted linear regression model has traditionally been used for calibration, but it is not necessarily the optimal model in all cases. Because the assumption of homoscedasticity was not met for the analytical data in this work, a weighted least squares linear regression was used for the calibration method. The evaluated analytical parameters were satisfactory for the analytes and showed recoveries at four fortification levels between 62% and 107%, with relative standard deviations less than 14%. The detection limits ranged from 7.6 to 24.1 ng L(-1). The proposed method was used to determine the amount of UV filters in water samples from water treatment plants in Araraquara and Jau in São Paulo, Brazil.

Multiresidue determination of carbamate, organochlorine, organophosphorus, and dicarboximide pesticides in lettuce by GC/MS.

An extraction method based on matrix solid-phase dispersion was developed to determine pirimicarb, methyl parathion, malathion, procymidone, alpha-endosulfan and beta-endosulfan in lettuce using gas chromatography-mass spectrometry. The best results were obtained using 4.0 g of lettuce, 2.0 g of silica as dispersant sorbent, 0.1 g of activated carbon as clean up sorbent and acetonitrile as eluting solvent. The method was validated using lettuce samples fortified with pesticides at six different concentration levels (0.1 to 2.0 mg/kg). Average recoveries (7 replicates) ranged from 50 to 120%, with relative standard deviations between 0.6 and 8.0%. Detection and quantification limits for lettuce ranged from 0.01 to 0.02 mg/kg and 0.04 to 0.10 mg/kg, respectively.