Low-temperature partitioning extraction followed by liquid chromatography tandem mass spectrometry determination of multiclass antibiotics in solid and soluble wastewater fractions.

An analytical method based on low-temperature partitioning extraction (LTPE) followed by high performance liquid chromatography coupled to triple quadrupole mass spectrometry analysis was developed and validated for the determination of eight multiclass antibiotics in wastewater. The analyzed target antibiotics included one ß-lactam, two sulfonamides, three fluoroquinolones, one macrolide and one diaminopyrimidine. LTPE parameters such as sample pH, volume ratio between sample and extractor solvent, ultra-sonic extraction time, extraction tube material, solvent and volume to reconstitute the sample extracts, were optimized. Additionally, the influence of solids on extraction efficiency was evaluated. Quantification of the target antibiotics was performed by double consecutive injection method, without the use of a labeled compound, in order to correct matrix effects. The whole samples were analyzed, including, liquid and solid fractions of wastewater. The results revealed that the filtration step can underestimate the total antibiotics concentration, particularly to the hydrophobic compounds that have higher affinity for solids, indicating that the suspended wastewater particulate should not be neglected. The method detection limit ranged from 18.54 ng L-1 (trimethoprim) to 78.49 ng L-1 (ciprofloxacin). Intra-day precision of less than 12.3% was achieved. The recoveries values ranged from 13.9% (sulfadiazine) to 48.9% (erythromycin) in influent samples and from 19.1% (sulfadiazine) to 57.2% (ciprofloxacin) in effluent samples. The method was applied to the measurement of antibiotic residues in influent and effluent from wastewater treatment plants. The majority target antibiotics were detected in wastewater samples. Their concentrations ranged from 237 to 9553 ng L-1 in influent and from 212 to 1660 ng L-1 in effluent. This work provides new insights on the applicability of LTPE for antibiotic residues extraction from wastewater. In addition, the performed analysis highlights the importance of measuring total concentrations of analytes in whole sample.

Aqueous chlorination of herbicide metribuzin: Identification and elucidation of "new" disinfection by-products, degradation pathway and toxicity evaluation.

A widely used herbicide, metribuzin, was evaluated for degradation, mineralization and disinfection by-products (DBPs) formation during aqueous chlorination. In addition, to assess the toxicity effects of chlorination on metribuzin solution the following tests were performed: acute toxicity using Artemia salina nauplii; cell viability using MTT assay; estrogenicity using a re-engineered Bioluminescent Yeast Estrogen Screen (BLYES) and a constitutively bioluminescent strain (BLYR); mutagenicity and developmental toxicity using Q(SAR) methodology. Metribuzin at 10 mg·L-1 was degraded by chlorination, achieving 93% of removal at 30 min of reaction. TOC analysis showed that the herbicide does not suffer complete mineralization, even after 24 h of contact with free chlorine. Seventeen DBPs were detected and their structural formulae were elucidated by high resolution mass spectrometry. Toxicity effects for chlorinated solutions increased when compared to the unreacted metribuzin solution. DBPs were more toxic to Artemia salina nauplii, increasing around 20% on nauplii mortality. It was also observed high estrogenicity to human receptors in BLYES assays and mutagenic and developmental toxicant effects to animals and humans in Q(SAR) methodology, suggesting that DBPs are potentially more toxic than the precursor metribuzin. Metribuzin solutions at 10 mg·L-1 showed equivalent 17-ß-estradiol values ranged from 0.061 to 6.71 µg·L-1 after to be chlorinated at different reaction times.

Preliminary assessment of antimicrobial activity and acute toxicity of norfloxacin chlorination by-product mixture.

Among drugs and personal care products, antibiotics arouse interest since they are widely used in human and veterinary medicine and can lead to the development of bacterial resistance. Usually, sewage treatment does not remove most of these compounds. So, these drugs can reach water treatment plants (WTP), where disinfection with chlorine compounds is common. This work aimed to evaluate the antimicrobial activity and preliminary toxicity of the mix of by-products forming due to the chlorination of norfloxacin. This is a fluoroquinolone antibiotic indicated for the treatment of urinary infection and gonorrhea, with sodium hypochlorite (NaClO). The drug was subjected to chlorination tests, on a bench scale, with several reaction times (from 5 min to 24 h). Analyses of high-resolution mass spectrometry (MS) were performed for the characterization of the by-products. The MS results showed five peaks attributed to the by-products' formation, of which four were identified. The antibiogram results indicated that the solution that contained the mixture of the by-products lost antibacterial activity against the E. coli strain studied. The acute toxicity tests for the Artemia salina microcrustacean showed that the blend of the by-products exhibited higher toxicity than pure norfloxacin.

Can high rate algal ponds be used as post-treatment of UASB reactors to remove micropollutants?

The present study evaluated the removal capacity of a UASB-HRAP treatment system, combining anaerobic and microalgae-based, aerobic treatment, for eleven organic micropollutants present in raw sewage, including pharmaceuticals, estrogens and xenoestrogens. The UASB reactor and the HRAP were operated at a hydraulic retention time (HRT) of 7 h and 8 days, respectively. Influent and effluent samples from the UASB and HRAP were collected periodically. All the target compounds were detected in raw sewage, with an occurrence ranging from 70 to 100%. Removal rates in the UASB reactor were generally incomplete, ranging from no removal (-25.12% for the hormone EE2-ethinylestradiol) to 84.91% (E2 - estradiol). However, the overall performance of the UASB + HRAP system was highly efficient for the majority of the compounds, with removal rates ranging from 64.8% (ibuprofen) to 95% (estrone). Gemfibrozil and bisphenol A were the only exceptions, with overall removal rates of 39% and 43%, respectively. Hormones were the compounds with the highest removal rates in the system.

Method development for simultaneous determination of polar and nonpolar pesticides in surface water by low-temperature partitioning extraction (LTPE) followed by HPLC-ESI-MS/MS.

During this research, chemometric approaches were applied for optimization of the low-temperature partitioning extraction (LTPE) for the simultaneous analysis of the pesticides: acephate, difenoconazole, fenamidone, fluazifop, fluazinam, methamidophos, and thiamethoxam from surface water samples and determination by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. It was used the 23 full factorial and the Doehlert experimental designs. The extraction technique was optimized by evaluating the effects of the three variables: sample pH, ionic strength (addition of Na2HPO4), and organic solvent volume. Considering the interest to find an optimal condition for all analytes simultaneously, the best extraction parameters found were as follows: pH = 5.33, concentration of Na2HPO4 = 0.0088 mol L-1 and organic phase volume = 4.5 mL. The optimized methodology showed LOD and LOQ levels from 0.33 to 8.13 ng L-1 and from 1.09 to 26.84 ng L-1, respectively. The recovery values ranged from 38.37 and 99.83% and the RSD values varied from 2.33 to 18.92%. The method was applied to surface water analysis sampled in areas with intensive agricultural practices in Ouro Branco City, Minas Gerais, Brazil. The difenoconazole was detected in concentrations between 12.53 and 94.76 ng L-1.

Ocorrência de fármacos e desreguladores endócrinos em esgoto bruto e tratado na cidade de Belo Horizonte (MG) / Occurrence of drugs and endocrine disrupters in raw and treatment sewage in the city of Belo Horizonte / MG, Brazil

RESUMO Os compostos de preocupação emergente (contaminants of emerging concern - CECs) atingem constantemente os corpos d'água via lançamento de esgoto sanitário, efluentes industriais e lixiviados de aterro, disposição inadequada de resíduos sólidos e escoamento superficial, ocasionando a poluição dos cursos d'água. Geralmente estes se encontram em concentrações da ordem de nanograma por litro ou micrograma por litro, dificultando sua análise ou onerando esse processo, demandando, assim, o desenvolvimento de técnicas de preparo e extração. Nesse contexto, destaca-se a Partição a Baixa Temperatura (EPBT), que se baseia na partição do analito de interesse entre fase aquosa e fase orgânica. Face ao exposto e à relevância do tema, o presente trabalho teve como objetivo avaliar, pelo uso da EPBT e cromatografia gasosa acoplada à espectrometria de massas, a ocorrência de 16 CECs no esgoto bruto e no tratado de Belo Horizonte (MG).

ABSTRACT Contaminants of Emerging Concern (CECs) constantly reach water bodies through the discharge of sanitary sewage, industrial effluents and landfill leachate, inadequate disposal of solid waste and surface runoff, causing the pollution of watercourses. In general, these are in concentrations of the order of mg / L or ng / L, making it difficult to analyze or burden this process, thus requiring the development of preparation and extraction techniques. In this context, it stands out the Low Temperature Patitioning Extraction (LTPE), which is based on the partition of the analyte of interest between aqueous phase and organic phase. Bearing this and the relevance of the subject in mind, the present work had the objective of evaluating the occurrence of 16 CECs in the crude and treated sewage of Belo Horizonte / MG, by using LTPE and gas chromatography coupled to mass spectrometry.

Determination of nine pharmaceutical active compounds in surface waters from Paraopeba River Basin in Brazil by LTPE-HPLC-ESI-MS/MS.

A simple, inexpensive, versatile, and environment-friendly extraction method, using low-temperature partitioning extraction (LTPE), was validated to quantify pharmaceutical-active compounds (PhACs) in surface water samples by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The PhACs analyzed were acetaminophen, bezafibrate, diclofenac, diltiazem, fluconazole, linezolid, miconazole, ondansetron hydrochloride, and trimethoprim. The detection and quantification limits ranged from 0.15 to 12.30 ng L-1 and 0.43 to 40.60 ng L-1, respectively. Recovery rates ranged from 46 to 135%, and relative standard deviation (RSD%) varied between 0.49 and 6.13%. This method was applied to monitor water contamination by PhACs in the Paraopeba River Basin (PRB), Minas Gerais state, Brazil. All PhACs, except linezolid which was not detected, were found in PRB water samples in concentrations that ranged from 2.6 ng L-1 to 2.62 µg L-1.

Behavior of pharmaceuticals in UV photoreactors fed with sewage treated by anaerobic/aerobic system.

This work has assessed the seasonal changes and the dynamics in the concentration of six pharmaceutical compounds during photolysis as a tertiary treatment of sewage previously treated by an anaerobic/aerobic system comprising a UASB (Upflow Anaerobic Sludge Blanket) reactor and a trickling filter (TF). The target compounds were four antibiotics (ciprofloxacin (CPF), clindamycin (CLM), sulfamethoxazole (SMX), and trimetoprim), one ß-blocker (atenolol), and one anti-inflammatory (diclofenac (DCF)). Six hydraulic retention times (HRTs) were evaluated (5, 10, 20, 40, 80, and 160 min) with the intent of varying the ultraviolet C (UVC) radiation doses applied to the effluent from biological treatment containing the target contaminants. The concentrations of pharmaceutical compounds in the effluent of the UASB/TF system were in agreement with the concentration levels reported in the literature. Aside from DCF, the seasonality seems to be a preponderant characteristic regarding the pharmaceutical concentration found in the effluent of biological treatment systems. The radiation dose of 117 mJ cm-2 seemed to be most suited for the photolysis application to tertiary treatment of domestic effluents. It was observed that lower UVC doses led to deconjugation of pharmaceuticals, which can result in increased concentrations of target pollutants in the photoreactor effluent.

Validation of a new high-throughput method to determine urinary S-phenylmercapturic acid using low-temperature partitioning extraction and ultra high performance liquid chromatography-mass spectrometry.

A new highly sensitive and environmentally friendly analytical method, using low-temperature partition extraction and ultra-high-performance liquid chromatography with tandem mass spectrometry, without the use of a labeled analyte, was developed and validated to determine and quantify urinary S-phenylmercapturic acid in urine samples. The World Health Organization, in its guidelines for air quality in Europe, recognizes that benzene is carcinogenic to humans and there is no safe level of exposure. Urinary S-phenylmercapturic acid is a sensitive and specific biological marker of exposure to benzene. The new analytical method, extraction, and analysis, were linear in the working range between 0.1 and 200.0 µg/L, precise (relative standard deviation lower than 6.0%), accurate (97.0-105.0%), and sensitive. The method's limits of detection and quantification were 0.02 and 0.084 µg/L, respectively. The recovery with the low-temperature partition extraction was 96.1%, with relative standard deviation less than 3.8%. The method is simple, accurate, and reproducible, and has been successfully applied in the evaluation of nonoccupational exposure to benzene, by urinary S-phenylmercapturic acid in urine samples.

Uso de fotorreatores UV para a remoção de diclofenaco, bezafibrato e etinilestradiol de esgoto tratado em sistema UASB-FBP / Use of UV photoreactors to remove diclofenac, bezafibrate and ethynylestradiol from sewage treated in UASB-TF system

RESUMOEste trabalho avaliou a remoção de diclofenaco (DCF), bezafibrato (BZF) e etinilestradiol (EE2) de efluentes de sistema UASB-FBP (reator anaeróbio de manta de lodo seguido de filtro biológico percolador) em fotorreatores UV de lâmpadas imersas (FRI) e emersas (FRE). Os resultados mostram que baixa eficiência de remoção de tais compostos foi obtida em ambos fotorreatores quando se utilizou baixo tempo de contato (~10 min) e baixa concentração inicial de fármacos (0,5 µg.L-1 para EE2, e 21 µg.L-1 para DCF e BZF). O aumento da concentração inicial de DCF (para 20 mg.L-1) e do tempo de contato (para 20 min) resultaram em aumento da eficiência de remoção (de 31 para 83% no FRI e de 36 para 86% no FRE), indicando que compostos dissolvidos presentes no efluente biológico afetaram adversamente a remoção de fármacos nos fotorreatores devido a competição pela radiação UV incidente.

ABSTRACTThis paper evaluated the removal of diclophenac (DCF), bezafibrate (BZF) and ethynylestradiol (EE2) from effluent of an anaerobic reactor coupled to a trickling filter (UASB-TF) in two types of UV photoreactors (immerse UV lamps - FRI and emmersed UV lamps - FRE). The results showed low removal efficiencies in both photoreactors when low contact times (10 min) and low initial concentration of such compounds was used (0.5 µg.L-1 for EE2 and 21 µg.L-1 for DCF and BZF). An increase in the initial concentration of DCF (to 20 mg.L-1) and of the contact time (to 20 min) led to an increase in the removal efficiency (from 31 to 83% in FRI and from 36 to 86% in FRE), suggesting that dissolved compounds present in the biological effluent adversely affected the removal of the pharmaceutical tested due to competition for the incident UV radiation.

Biotechnological potential of yeast isolates from cachaça: the Brazilian spirit.

This study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were verified: capacity to use alternative carbon sources; ability to tolerate high concentrations of sucrose, ethanol, methanol, aluminum and zinc as well as different pH values and foam production. Pichia guilliermondii and Pichia anomala strains were identified as the most promising ones for application in the second-generation biofuel industry, showing ability to grow on high glycerol concentrations. Other isolates, identified as Saccharomyces cerevisiae, produced bioethanol comparable to the industrial strains, and were therefore ideal for use in the first-generation ethanol industry. Some of these strains also showed high resistance to aluminum, as observed in sugarcane juice, and to inter-cycle washings with diluted sulphuric acid, as performed in the industrial bioethanol production process. In summary, yeast isolates from cachaça distilleries displayed robustness and phenotypic plasticity, which makes them interesting for biotechnological applications.

Photodegradation of bisphenol A in aqueous medium: monitoring and identification of by-products by liquid chromatography coupled to high-resolution mass spectrometry.

RATIONALE: Environmental bisphenol A (BPA) contamination is currently a matter of concern. This compound can disrupt the endocrine system by mimicking natural hormones and cause adverse effects on different organisms. In addition, it has been suggested that BPA can impair brain development, especially in fetuses and children. To efficiently remove BPA from contaminated water and wastewaters, several emerging technologies have been developed. Most are based on photodegradation. However, by-products resulting from the application of such methods have not been properly characterized. METHODS: The photodegradation of BPA was conducted using two different methods: photocatalysis (TiO2/UV-A and TiO2/UV-C systems) and direct photolysis (UV-A and UV-C radiation). The degradation process was continuously monitored to identify and observe the by-products formed under these conditions. Direct infusion electrospray ionization coupled to high-resolution mass spectrometry in negative ion mode [ESI(-)-HRMS] and liquid chromatography coupled to high-resolution mass spectrometry (HPLC/HRMS) were employed to monitor these by-products. RESULTS: The results revealed that the TiO2/UV-C system was the most efficient in causing both BPA depletion and mineralization of the organic matter in solution. Moreover, accurate mass data allowed for the assignment of molecular formulae for seven by-products, many of them unprecedented, formed under these conditions. Thus, a route for the photodegradation of BPA in aqueous medium could be proposed based on these results. Finally, additional tests revealed that the by-products showed a higher toxicity against Artemia salina than the primary precursor. CONCLUSIONS: All of these findings indicate that the identification of by-products arising from oxidative treatments is of primary importance because such compounds can be more hazardous than their precursors.

Photolysis and photocatalysis of ibuprofen in aqueous medium: characterization of by-products via liquid chromatography coupled to high-resolution mass spectrometry and assessment of their toxicities against Artemia salina.

The degradation of the pharmaceutical compound ibuprofen (IBP) in aqueous solution induced by direct photolysis (UV-A and UV-C radiation) and photocatalysis (TiO2 /UV-A and TiO2 /UV-C systems) was evaluated. Initially, we observed that whereas photocatalysis (both systems) and direct photolysis with UV-C radiation were able to cause an almost complete removal of IBP, the mineralization rates achieved for all the photodegradation processes were much smaller (the highest value being obtained for the TiO2 /UV-C system: 37.7%), even after an exposure time as long as 120 min. Chemical structures for the by-products formed under these oxidative conditions (11 of them were detected) were proposed based on the data from liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) analyses. Taking into account these results, an unprecedented route for the photodegradation of IBP could thus be proposed. Moreover, a fortunate result was achieved herein: tests against Artemia salina showed that the degradation products had no higher ecotoxicities than IBP, which possibly indicates that the photocatalytic (TiO2 /UV-A and TiO2 /UV-C systems) and photolytic (UV-C radiation) processes can be conveniently employed to deplete IBP in aqueous media.

Validacao de metodo de cromatografia liquida para a determinacao de sete acidos graxos volateis intermediarios da digestao anaerobia / Validation of a liquid chromatography methodology for the analysis of seven volatile fatty acids intermediates of anaerobic digestion

Ácidos graxos voláteis (AGV) são importantes compostos intermediários indicadores da digestão anaeróbia. Este artigo apresenta dados de validação de uma metodologia para análise de uma mistura de sete AGV (C1 a C5) em amostras ambientais por cromatografia líquida de alta eficiência (CLAE). Foi utilizada uma coluna de exclusão iônica a 55ºC, volume de injeção de 10 µL e fase móvel (0,01 mol.L-1 H2SO4) a 0,6 mL.min-1. Os critérios de validação foram: limites de detecção e de quantificação, que ficaram na faixa de 5,0 a 10 mg.L-1 e 15 a 30 mg.L-1, respectivamente; linearidade (comprovada para todos os ácidos); repetitividade e sensibilidade (muito boa para a maioria dos ácidos); efeito de matriz (efeito de supressão observado para o ácido isobutírico) e exatidão (85 a 104%). Sendo assim, as condições operacionais adotadas se mostraram válidas para a quantificação de AGV em efluentes de reatores anaeróbios.

Volatile fatty acids (VFA) are important intermediate compounds that somehow indicate the efficiency of anaerobic systems. This paper presents results of method validation for seven VFA (C1 to C5) analysis in environmental samples by high performance liquid chromatography (HPLC). It was used an ion exclusion column kept at 55ºC; injection volume of 10 μL and mobile phase (0.01 mol.L-1 H2SO4) at 0.6 mL.min-1. The validation criteria adopted were: limits of detection and quantification, that fell in the ranges of 5.0 -10 mg.L-1 and 15-30 mg.L-1, respectively; linearity (verified for all acids); repeatability and sensibility (very good for most acids); matrix effect (suppression effect observed for isobutyric acid) and accuracy (from 85 to 104%). Therefore, the operational conditions adopted seemed to be adequate and valid to measure VFA in samples from anaerobic reactors.

Ozonation of the food dye Brilliant Blue in aqueous medium: monitoring and characterization of products by direct infusion electrospray ionization coupled to high-resolution mass spectrometry.

RATIONALE: Dyes have been widely used to accentuate or to provide different colors to foods. However, the high concentrations of dyes in effluents from the food industries can cause serious and unpredictable damages to aquatic life in general. Furthermore, since conventional biological treatments have been shown to be ineffective, the use of advanced oxidation processes to promote the depletion of such dyes in water bodies has turned out to be mandatory. METHODS: The degradation of the food dye Brilliant Blue by ozone in aqueous solution is reported herein. The overall process was monitored in real time by using direct infusion electrospray ionization high-resolution mass spectrometry in the negative ion mode, ESI(-)-HRMS. RESULTS: Preliminary results (visual inspection and UV-vis spectra) showed the high efficiency of ozonation in causing the decoloration of an aqueous solution of the dye whereas TOC (total organic carbon) measurements revealed that such an oxidation process was unable to promote its complete mineralization. ESI(-)-HRMS data showed that the substrate consumption occurred concomitantly with the appearance of four by-products, all of them produced by an initial attack of hydroxyl radicals (generated via the decomposition of ozone) on the two imino moieties of the dye molecule. Structures were proposed for all the by-products based mainly on the high-resolution mass measurements and on the characteristic reactivity of typical functional groups towards hydroxyl radicals. An unprecedented degradation route of Brilliant Blue by ozone in aqueous solution could thus be proposed. CONCLUSIONS: A greater ecotoxicity against Artemia salina was observed for the by-products than for the original dye. This indicates that the identification of by-products arising from oxidation treatments is of primary importance since such compounds can be more hazardous than the precursor itself.

Avaliaçäo da presença de pesticidas N-Metilcarbamatos e seus produtos de degradaçäo nas águas da regiäo de Pará e Minas (MG) Brasil / Evaluation of the presence of N-Methylcarbamate pesticides and degradation products in waters of Pará de Minas (MG) region in Brazil

Os pesticidas N-metilcarbamatos e alguns de seus metabólitos säo altamente tóxicos para o homem e o meio ambiente. Por esta razäo desenvolveu-se método analítico utilizando extraçäo em fase sólida e cromatografia líquida de alta eficiência com detector de ultravioleta (CLAE/UV) para análise destes compostos em amostras de água. O método apresentou índice de recuperaçäo para 10 compostos de 57 a 99 por cento, com desvio padräo relativo (CV) de 5,67 a 7,67 por cento para n=6. A repetitividade do método forneceu CV entre 5,94 a 8,46 por cento para n=6. O limite de detecçäo do método (MDL) situou-se na faixa de 0,07 a 0,38 ug/L para 10 compostos. Este método foi aplicado na análise de amostras de águas coletadas na cidade de Pará de Minas - MG, Brasil e também em alguns pontos selecionados nas bacias dos Rios Paciência e Bom Sucesso, situadas no município de Pará de Minas. Os resultados das análises em amostras de água mostraram-se abaixo dos limites estabelecidos pela legislaçä brasileira