Ydepatterson2322

Analytical curves presented regression coefficients values above 0.9908 for a concentration range from 0.005 to 0.6 μg g-1. Limits of detection (LOD) from 0.002 to 0.006 μg g-1 and limits of quantification (LOQ) from 0.006 to 0.020 μg g-1 were reached for all analytes. This method can be used to monitor and quantify fipronil and its intermediates in soil.Polypyrrole (PPy) is a polymer widely used as an extraction phase due to its ability to perform intermolecular interactions with the analyte, such as acid-base, π-π, dipole-dipole, hydrophobic, and hydrogen bonding. In this manuscript, we report the coating of a stainless steel needle with a PPy film for analyte extraction and subsequent analysis by electrospray ionization mass spectrometry (ESI-MS) under ambient and open-air conditions. The method, named PPy-ESI-MS, was optimized for analysis of 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) in synthetic urine. Seven cycles of electrodeposition of the PPy film onto the needle surface, sample at pH 8, and 40 min of extraction of analytes were determined as the best analysis conditions. The analytical performance of PPy-ESI-MS was evaluated for MDA and MDMA compounds. Analytical curves were obtained with R2 > 0.98. Limits of detection (LODs) and limits of quantification (LOQs) were determined as 20 μg L-1 and 70 μg L-1 for MDA and as 25 μg L-1 and 80 μg L-1 for MDMA, respectively. Values of precision were below 17%, and values of accuracy below 5%. The apparent recoveries ranged between 84.5% and 111.3%. In addition, the PPy-ESI-MS method was applied for the analysis of sarcosine in synthetic urine in order to evaluate the performance of the method for another class of compounds. The calibration curve was obtained with R2 > 0.98, along with LOD and LOQ of 30 μg L-1 and 100 μg L-1, respectively. The precision and accuracy values were below 5% and 8%, respectively, and the apparent recoveries close to 100%. This work demonstrates the usefulness of combining an extraction phase with ESI-MS analysis under ambient conditions to determine different classes of small molecules in a complex sample.Infant formula (IF) constitutes the sole source of mineral intake for infants who are only fed IF. The assurance of the amount of minerals declared on the label and the mineral levels and their chemical forms present a major concern related to providing a good amount of nutrients for absorption by these children. Thus, the objectives of this study were (i) to evaluate several sample preparation methods for minerals in IF; (ii) to validate an analytical method using an ultrasonic bath for simultaneous determination of the Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn contents in IF by ICP OES and (ii) to establish the optimum analytical conditions of the in vitro method to study the dialyzability of these minerals from IF. The ultrasound-assisted method was shown to conform to 'green chemistry principles', being simple, fast and low cost compared with reference methods. The results were similar to those obtained with reference methods (microwave-assisted acid digestion and dry ashing) with regard to selectivity, sensitivity and linearity (r2 > 0.999). The accuracy and the precision were verified using certified reference materials, with recoveries and coefficients of variation ranging from 91 to 105% and from 1.1 to 5.2%, respectively. For in vitro dialyzability, the conditions established in this study allowed including an overnight step between the gastric and gastrointestinal stages (accuracy and precision ranging from 81 to 108% and 0.4 to 6.3%, respectively), contributing to establishing an in vitro digestion method suitable for infant gastrointestinal conditions.Water contained in organic solvents or products in chemical industries, as contaminants, poses an adverse risk in chemical reaction, life or environmental safety. However, conventional fluorescent water sensing suffers from drawbacks, including limited organic solvents, narrow linear range, lack of visual detection, single detection strategy, and others. Herein, a novel type of red-emitting carbon dots (RCDs) has been created via one-step solvothermal synthesis based on biomass (e.g., lignin) as the carbon source and p-phenylenediamine (PPD) as the nitrogen source. Colorimetric and fluorometric detection of water in organic solvents has been demonstrated. find more The RCDs showed excitation-independent photoluminescence (PL) in different solvents and solvatochromic behavior, red in water, orange in ethanol, yellow in N,N-dimethyl formamide (DMF), and green in acetone. Remarkably, detection of water content in six organic solvents, including polar solvents (ethanol, acetone, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and DMF) and apolar solvent (ether), was performed. With increasing water content in solvents, emission colors changed from green to red, or yellow to red, offering qualitative sensing of water. Furthermore, a broad linear detection range (10-90%), low limits of detection (LOD) (e.g., 0.36% for ethanol and 0.082% for acetone), and good generality for various organic solvent systems were realized. Particularly, dual sensing strategies, including PL quenching and shift with water in various solvents, were achieved simultaneously, showing great potential for the development of advanced optical sensors with high performance.Dinitolmide is a nitro amide coccidiostat used in poultry feed, and is a potential threat to the environment and human health. In this study, a monoclonal antibody (mAb) against dinitolmide was prepared and an immunochromatographic assay (ICA) was developed to detect residual dinitolmide in chicken tissue. The results show that the mAb exhibited high sensitivity, with a limit of detection as low as 9.01 ng mL-1. A cross reactivity test revealed that the mAb also had good specificity for dinitolmide. This ICA method showed a visible limit of detection of 2.5 μg kg-1, and a cut-off value of 25 μg kg-1 for testing dinitolmide in chicken sample extract by using the naked eye. Importantly, these observations using our ICA, were comparable to other methods of detection such as liquid chromatography, tandem mass spectrometry and indirect competitive enzyme-linked immunosorbent assays (IC-ELISA). These data suggest that our ICA method is a reliable, portable, and high-throughput method for the detection of dinitolmide residues in chicken tissue.