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This study investigated the occurrence of tetracyclines (TCs), namely minocycline (MIN), TC, and its epimer epitetracycline (ETC), and doxycycline (DC), in four hospital wastewater effluents and its fate in municipal wastewater treatment plants (WWTPs), in Coimbra, Portugal. Analytical determination was carried out by solid-phase extraction followed by liquid chromatography with fluorescence detection. A gradient system with a mobile phase containing oxalic acid 0.02 M and acetonitrile was used. After postcolumn derivatization with magnesium reagent, TCs were detected at lambda(exc) 386 nm and lambda(em) 500 nm. The proposed method allowed good sensitivity, accuracy, and precision. LOQs were 0.5 microg l(-1) for ETC and TC and 15 and 5 microg l(-1) for MIN and DC, respectively. The recovery values ranged between 66.4% and 117.1%, and intraday and interday repeatability was lower than 6.8%. The method was successfully used to determine the presence of the above-mentioned TCs in 24 wastewater composite samples obtained from hospital effluents and from influent and effluent of the WWTP located in Coimbra, Portugal. MIN and TC were found in 41.7% of the samples; ETC and DC were found in 25% and 8.3% of the samples, respectively. The levels found ranged from 6 to 531.7 microg l(-1) in hospital effluents, while its concentrations in WWTP ranged from 95.8 to 915.3 microg l(-1). A seasonal influence in the concentrations found has also been observed, the levels found in samples collected during spring being higher than those observed in samples collected during autumn; however, these are only preliminary results. The WWTP removal rate ranged between 89.5% and 100%.

Ochratoxin A (OTA) is a secondary fungal metabolite produced by several moulds, mainly by Aspergillus ochraceus and by Penicillium verrucosum, that occurs in meat products. The aim of this work was to optimize an efficient extraction procedure for the determination of OTA in muscle tissue in order to assess its occurrence in meat samples. Three different apparatus, a Waring blender, a switching apparatus, and an ultrasonic processor, were evaluated to verify the efficiency of extraction. The analytical methods proposed involve the extraction with chloroform-orthophosphoric acid, cleanup through an immunoaffinity column, high-performance liquid chromatography/fluorescence detection for separation and identification of OTA, and confirmation with liquid chromatography/FD after methylation of OTA in muscle tissue. The limit of quantification of the proposed method was 0.04 microg kg(-1). Recoveries of OTA, using switching apparatus, ranged from 90.3 to 103.2% for chicken muscle spiked at 2.4 and 0.48 microg kg(-1), respectively, with a within-day relative standard deviation of 17 and 15.3%. The proposed method was applied to 38 chicken, swine, and turkey muscle samples and the presence of OTA was confirmed in five samples. Finally, the estimated daily intake of OTA in this study was between 23 pg kg(-1) body weight per day for swine samples and 18 pg kg(-1) body weight per day for turkey samples.

A total of 98 poultry samples, including chicken and turkey muscle, were analysed, using a sensitive and reliable analytical method based on liquid chromatography (LC) with spectrofluorimetric detection, for simultaneous determination of four fluoroquinolone (FQ) antibiotics, namely enrofloxacin (ENRO), ciprofloxacin (CIPRO), norfloxacin (NOR), and sarafloxacin (SARA). The method involved extraction with 0.15 mol L(-1) HCl and clean-up by solid-phase extraction using Oasis HLB cartridges. Chromatographic separation was carried out on a C(18) TSK gel column, in isocratic mode, with 0.025 mol L(-1) H(3)PO(4) solution, adjusted to pH 3.0 with tetrabutylammonium hydroxide-methanol (78:22) as mobile phase. Good linearity over the investigated concentration range was observed, with mean values of correlation coefficients higher than 0.9989 for all the analytes studied. The limits of quantification (LOQ), expressed as the lowest fortification level with acceptable precision were 15 microg kg(-1) for ENRO, CIPRO, and NOR, and 30 microg kg(-1) for SARA; these values are in compliance with requirements for monitoring of maximum residues levels (MRLs). Overall recoveries from spiked samples ranged from 80% to 92% with relative standard deviations (RSD) lower than 6.1%. Of the chicken and turkey samples analysed, 44.2% and 37.8%, respectively, were contaminated. The levels found in the analysed poultry samples, collected from markets of Oporto and Coimbra, located in the north and central zones of Portugal, respectively, were lower than 114.2 and 87.6 microg kg(-1) in chicken and turkey muscle samples, respectively. One positive chicken sample was contaminated with ENRO at levels higher than the MRL.

The present work shows the optimization and validation results of an analytical methodology based on immunoaffinity clean-up (IAC) followed by liquid chromatography with tandem mass detection (LC-MS-MS) for the analysis of the mycotoxins fumonisin B(1) (FB(1)) and B(2) (FB(2)) in human urine samples, in order to evaluate fumonisins exposure in two Portuguese populations. As far as we know, immunoaffinity clean-up procedure was used, for the first time, in the analysis of fumonisins (FBs) in urine. Using this analytical methodology, the limit of quantification achieved was 10 ng mL(-1) for FB(1) and for FB(2). Recoveries were higher than 73.4% for fortification levels between 10 and 100 ng mL(-1) and intra-day and inter-day repeatability were lower than 8.6%. The natural occurrence of FB(1) and FB(2) in 68 human urine samples obtained from the central zone of Portugal was studied. None of the studied samples presented detectable levels of FB(1) and FB(2).

The main goal of this work was determination of residues of the antibiotics ofloxacin (OFLO), norfloxacin (NOR), ciprofloxacin (CIPRO), and enrofloxacin (ENRO) in wastewater samples. The samples, after acidification to pH 4.5 and addition of EDTA, were extracted on an anion-exchange cartridge in tandem with an Oasis HLB cartridge. The LC–FD method, developed in previous studies, was based on application of a monolithic C18 column. The limit of quantification (LOQ) of the method was 250 ng L-1 for OFLO, 25 ng L-1 for NOR and CIPRO, and 50 ng L-1 for ENRO. Mean recovery ranged between 75 and 121% for OFLO, NOR, CIPRO, and ENRO. A total of 14 wastewater samples were analyzed; these were collected from four hospitals and from influent and effluent from a wastewater-treatment plant in Coimbra, Portugal, during spring and autumn. CIPRO was present in all the samples, NOR was detected second most often, followed by OFLO. ENRO was found at concentrations under the LOQ in five hospital samples, and the highest level was found in influent from the WWTP.