Bioproducts characterization of residual periphytic biomass produced in an algal turf scrubber (ATS) bioremediation system.

The transformation of residual biomass from bioremediation processes into new products is a worldwide trend driven by economic, environmental and social gain. The present study aimed to evaluate the potential for obtaining bioproducts of technological interest from the remaining periphytic biomass formed during a bioremediation process with an algal turf scrubber (ATS) system installed in a lake catchment. Different methodologies were used according to the target bioproduct. Analyses were performed by high performance liquid chromatography with diode array detector (HPLC/DAD), gas chromatography mass spectrometry (GC-MS), ultraviolet-visible spectroscopy (UV-VIS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The results demonstrated that the periphytic biomass presented potential since protein (17.7%), carbohydrates (22.4%), total lipids (3.3%) with 3.6 mg mL-1 of fatty acids, antioxidants (144.5 µmol Trolox eq. g-1) and chlorophyll a, chlorophyll b and carotenoids (1,719.7 µg mL-1, 541.2 µg mL-1 and 317.7 µg mL-1, respectively) were obtained. Inorganic analysis presented a value of 42.3 ± 2.58% of total ash and metal presence was detected, indicating bioaccumulation. The properties found in periphyton strengthen the possibility of its application in different areas, ensuring bioremediation efficiency.

Simultaneous determination of the quaternary ammonium pesticides paraquat, diquat, chlormequat, and mepiquat in barley and wheat using a modified quick polar pesticides method, diluted standard addition calibration and hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry.

In this study, a modified Quick Polar Pesticides (QuPPe) method, optimized by a central composite design, was developed to determine quaternary ammonium pesticides (QUATs) residues in barley and wheat by ultra-high-performance liquid chromatographic tandem mass spectrometry (UHPLC-MS/MS) using a hydrophilic interaction chromatography (HILIC) column. Considering the high polarity of these compounds, special conditions of sample preparation and analysis are required. Different mobile phases, extraction procedure and clean-up were evaluated. An isocratic elution with aqueous solution of ammonium formate 60 mmol L-1 (pH 3.7) and acetonitrile, 40:60 (v/v), was selected. Water and acidified methanol as extraction solvent, without heating, and a clean-up with dichloromethane, chitosan and acetonitrile presented good results. The validated method presented satisfactory selectivity, linearity, matrix effect, trueness and precision, providing recoveries from 93 to 110% with RSD < 13% for barley, and 70 to 115% with RSD < 18% for wheat. The complexity of these matrices requires the calibration in matrix and the diluted standard addition calibration (DSAC) procedure has been shown to be an excellent option to compensate for the matrix effect and the losses of the analytes in the extraction. Real samples of barley and wheat were analyzed and 60% presented concentrations of paraquat above the maximum limits allowed by the European Union. The modified QuPPe method combined with DSAC and HILIC-UHPLC-MS/MS demonstrated to be an effective approach to determine QUATs in barley and wheat, and is a good alternative for routine analysis. The use of the biosorbent chitosan is effective, low cost and more ecological when compared to others conventional sorbents.

Optimization of sample preparation by central composite design for multi-class determination of veterinary drugs in bovine muscle, kidney and liver by ultra-high-performance liquid chromatographic-tandem mass spectrometry.

In this study a simple and fast multi-class method for the determination of veterinary drugs in bovine liver, kidney and muscle was developed. The method employed acetonitrile for extraction followed by clean-up with EMR-Lipid® sorbent and trichloracetic acid. Tests indicated that the use of TCA was most effective when added in the final step of the clean-up procedure instead of during extraction. Different sorbents were tested and optimized using central composite design and the analytes determined by ultra-high-performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS). The method was validated according the European Commission Decision 2002/657 presenting satisfactory results for 69 veterinary drugs in bovine liver and 68 compounds in bovine muscle and kidney. The method was applied in real samples and in proficiency tests and proved to be adequate for routine analysis. Residues of abamectin, doramectin, eprinomectin and ivermectin were found in samples of bovine muscle and only ivermectin in bovine liver.

Multiresidue determination of pesticides in crop plants by the quick, easy, cheap, effective, rugged, and safe method and ultra-high-performance liquid chromatography tandem mass spectrometry using a calibration based on a single level standard addition in the sample.

In this study, a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, optimized by a 23 full factorial design, was developed for the determination of 72 pesticides in plant parts of carrot, corn, melon, rice, soy, silage, tobacco, cassava, lettuce and wheat by ultra-high-performance liquid chromatographic tandem mass spectrometry (UHPLC-MS/MS). Considering the complexity of these matrices and the need of use calibration in matrix, a new calibration approach based on single level standard addition in the sample (SLSAS) was proposed in this work and compared with the matrix-matched calibration (MMC), the procedural standard calibration (PSC) and the diluted standard addition calibration (DSAC). All approaches presented satisfactory validation parameters with recoveries from 70 to 120% and relative standard deviations≤20%. SLSAS was the most practical from the evaluated approaches and proved to be an effective way of calibration. Method limit of detection were between 4.8 and 48µgkg-1 and limit of quantification were from 16 to 160µgkg-1. Method application to different kinds of plants found residues of 20 pesticides that were quantified with z-scores values≤2 in comparison with other calibration approaches. The proposed QuEChERS method combined with UHPLC-MS/MS analysis and using an easy and effective calibration procedure presented satisfactory results for pesticide residues determination in different crop plants and is a good alternative for routine analysis.

Dilution standard addition calibration: A practical calibration strategy for multiresidue organic compounds determination.

Among calibration approaches for organic compounds determination in complex matrices, external calibration, based in solutions of the analytes in solvent or in blank matrix extracts, is the most applied approach. Although matrix matched calibration (MMC) can compensates the matrix effects, it does not compensate low recovery results. In this way, standard addition (SA) and procedural standard calibration (PSC) are usual alternatives, despite they generate more sample and/or matrix blanks consumption need, extra sample preparations and higher time and costs. Thus, the goal of this work was to establish a fast and efficient calibration approach, the diluted standard addition calibration (DSAC), based on successive dilutions of a spiked blank sample. In order to evaluate the proposed approach, solvent calibration (SC), MMC, PSC and DSAC were applied to evaluate recovery results of grape blank samples spiked with 66 pesticides. Samples were extracted with the acetate QuEChERS method and the compounds determined by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Results indicated that low recovery results for some pesticides were compensated by both PSC and DSAC approaches. Considering recoveries from 70 to 120% with RSD <20% as adequate, DSAC presented 83%, 98% and 100% of compounds meeting this criteria for the spiking levels 10, 50 and 100µgkg(-1), respectively. PSC presented same results (83%, 98% and 100%), better than those obtained by MMC (79%, 95% and 97%) and by SC (62%, 70% and 79%). The DSAC strategy showed to be suitable for calibration of multiresidue determination methods, producing adequate results in terms of trueness and is easier and faster to perform than other approaches.

Optimization of a QuEChERS based method by means of central composite design for pesticide multiresidue determination in orange juice by UHPLC-MS/MS.

In this study, different extraction procedures based on the QuEChERS method were compared for the multiresidue determination of pesticides in orange juice by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). After choosing preliminary conditions, an experimental design was carried out with the variables C18, PSA, NaOH and CH3COONa to optimize the sample preparation step. The validation results of the validation were satisfactory, since the method presented recoveries between 70% and 118%, with RSD lower than 19% for spike levels between 10 and 100 µg L(-1). The method limit of detection (LOD) and limit of quantification (LOQ) ranged from 3.0 to 7.6 µg L(-1) and from 4.9 to 26 µg L(-1), respectively. The method developed was adequate for the determination of 74 pesticide residues in orange juice.

Acute exposure to the biopesticide azadirachtin affects parameters in the gills of common carp (Cyprinus carpio).

The biopesticide, azadirachtin (Aza) is less hazardous to the environment, but may cause several toxic effects in aquatic organisms. The Cyprinus carpio (n=12, for all concentrations) after 10days of acclimation under controlled conditions, were exposed at 20, 40, and 60µL/L of Aza during 96h. After this period, fish were anesthetized and euthanized then mucus layer and gills collected. In this study, the effects of exposure to different Aza concentrations were analysed through a set of biomarkers: Na(+)/K(+-)ATPase, lipid peroxidation (TBARS), protein carbonyl (PC), superoxide dismutase (SOD), glutathione-S-transferase (GST), catalase (CAT), glutathione peroxidase (GPx), non-protein thiols (NPSH), ascorbic acid (AsA) and histological parameters and, yet, protein and glucose concentration in the surface area of mucous layer. Na(+)K(+-)ATPase was inhibited at 40 and 60µL/L compared to control. TBARS decreased at 40µL/L compared to control. PC, SOD and GST increased at 60µL/L in comparison to control. CAT increased at 20 and 60µL/L, and GPx increased in all Aza concentrations compared to control. NPSH decreased and AsA increased in all concentrations in comparison to control. Histological analyses demonstrated an increase in the intensity of the damage with increasing Aza concentration. Alterations in histological examination were elevation and hypertrophy of the epithelial cells of the secondary filament, hypertrophy and hyperplasia of the mucous and chlorate cells and lamellar aneurism. Glucose and protein concentrations in mucus layer increased at 60µL/L compared to control. In general, we suggest that 60µL/L Aza concentration affected several parameters causing disruptions carp metabolism.