Covingtonmooney9332

2 ng μL-1. The genosensor had a very good selectivity, fabrication reproducibility and stability, and was applicable for practical applications.This research describes a solid-phase microextraction device using carbon nanomaterials supported on steel threads. The device was used to pre-concentrate and extract 24 pesticides in water. The carbon nanomaterials were obtained by a chemical vapor deposition (CVD) process, using methane and acetonitrile as carbon source. The different pesticides were separated, detected, and quantified using gas chromatography coupled to mass spectrometry (GC-MS). The system, optimized and validated in the laboratory, presented good results. Linearity was between 0.0007 and 50.00 μg L-1, with determination coefficients greater than 0.9. The detection and quantification limits were in the range of 0.0002-1.1309 μg L-1 and 0.0007-3.7320 μg L-1, respectively. The studied pesticides presented recovery values in the range of 70 ± 8 to 123 ± 18%. Carbon nanomaterials exhibited high thermal and mechanical resistance, as the same fiber could be used for approximately 300 extractions. The device was applied to analyze environmental water samples collected from the São Francisco river basin in Brazil and in the Chinampas in Mexico City.Quantitative analysis under various perturbations is a difficult problem because the analytical signal changes with different factors. In this work, three-level simultaneous component analysis (3-MSCA) was used for analyzing the near-infrared (NIR) spectra of aqueous solutions under different perturbations. The spectral data of aqueous proline solutions at different pH, concentration and temperature were measured, and a three-level model was built to describe the effects of the three perturbations on the spectra, respectively. The first level model describes the change of the spectra with pH, from which significant aggregation of proline was observed around the isoelectric point. The second and third level model show the spectral change with concentration and temperature, respectively, and the spectral feature has a very good linear relationship with the corresponding influencing factors. Therefore, the pH and concentration scores can be used as the calibration curve for quantitative analysis of the pH and the content of proline, and the temperature scores can be used to predict the temperature of the solutions. In addition, the structural change of water molecules under different conditions is obtained from the loadings. A decline of the bulk water was found with the increase of concentration, implying an ascending trend of the bonded water due to the interaction of proline and water. The dissociation of water clusters with the increase of temperature is also displayed.In this study, a multi ion-selective electrode system was developed for simultaneous determination of Ca2+, Mg2+, K+ and NH4+ ions. The system, called electronic tongue, was used for the quantitative determination of these ions in different water samples. The measurement system was comprised of sixteen ion-selective electrodes, an Ag/AgCl double-junction reference electrode, and a sixteen-channel multi-potentiometer. In the fabrication process of the electronic tongue, an electrode body, which comprised eight ion-selective electrodes together on it, was designed. The obtained data were evaluated by using multivariate calibration methods such as Classical Least Squares (CLS), Principal Component Regression (PCR) and Partial Least Squares (PLS1). The parameters that influence the electronic tongue performance were investigated. Analyses were conducted in synthetic water samples and real water samples. Percentage recovery values in synthetic samples, which were calculated via PLS1, were found 101.35%, 102.41%, 100.04% and 99.23% for Ca2+, Mg2+, K+ and NH4+ respectively. The results, obtained from the electronic tongue and other analytical techniques, were compared and no significant difference was found between the results at 95% confidence level.We developed hydrophilic interaction chromatography (HILIC)-type sorbents modified with nucleobases for solid phase extraction (SPE). The synthesized hydrophilic base resins were modified by each nucleobase (adenine, guanine, and cytosine). The measurement of the amount of water content indicated that each nucleobase-modified sorbent had a water layer. To evaluate the adsorption properties in the HILIC mode, we chose two nucleobases (uracil and adenine) and four nucleosides (uridine, adenosine, cytidine, guanosine) as water-soluble analytes, which were loaded into an SPE cartridge packed with the nucleobase-modified sorbent. Firstly, 95% acetonitrile (ACN) solutions were used in the process of conditioning and sample loading of the above polar analytes. High recoveries of the analytes were observed in each nucleobase-modified sorbent, and the Diol-type sorbent (no modification with any of the nucleobases) did not adsorb each water-soluble analyte. On the basis of this result, a 98% ACN solution was used durinportant for retention in the HILIC-type sorbent.Owing to the risks and dangers of xenobiotic cannabinoids (phyto and synthetic), studies are required to evaluate community consumption. SC-43 price The analysis of excreted cannabinoids in wastewater can provide information about community consumption for a defined catchment area. The recovery of cannabinoids from complex wastewater matrices is difficult due to the hydrophobic properties of these compounds. In this study, a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was optimised for the recovery of 30 cannabinoids from wastewater, including the cannabis urinary biomarker 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), cannabidiol (CBD), and a variety of different generational synthetic cannabinoids and metabolites. Method validation assessed criteria including linearity, selectivity, recovery, ion-suppression, filtration losses and matrix effect. Two sample preparation approaches-liquid-liquid extraction (LLE) and solid phase extraction (SPE)-were compared, with comparable limits of quantification between 0.001 and 0.5 µg L-1 in wastewater. Filtration was found to reduce the recovery for many of the investigated cannabinoids, where up to 97% of analyte was lost. The method was applied to 15 different catchment areas across Australia to gauge the community use of the cannabinoids in this study. The cannabis biomarker THC-COOH was quantified at all locations, and cannabidiol was measured at eight catchment areas. Three synthetic cannabinoids were detected at the limit of detection 5-fluoro APINACA, JWH-073 (4-hydroxypentyl), and MDMB-CHMICA.