Time Intensity Q1Q2 CID ASAP Probe Corona ConeAbstract. Amphetamine-type stimulants (ATS) are among illicit stimulant drugs that are most often used worldwide. A major challenge is to develop a fast and efficient methodology involving minimal sample preparation to analyze ATS in biological fluids. In this study, a urine pool solution containing amphetamine, methamphetamine, ephedrine, sibutramine, and fenfluramine at concentrations ranging from 0.5 pg/mL to 100 ng/mL was prepared and analyzed by atmospheric solids analysis probe tandem mass spectrometry (ASAP-MS/MS) and multiple reaction monitoring (MRM). A urine sample and saliva collected from a volunteer contributor (V1) were also analyzed. The limit of detection of the tested compounds ranged between 0.002 and 0.4 ng/mL in urine samples; the signal-to-noise ratio was 5. These results demonstrated that the ASAP-MS/MS methodology is applicable for the fast detection of ATS in urine samples with great sensitivity and specificity, without the need for cleanup, preconcentration, or chromatographic separation. Thus ASAP-MS/MS could potentially be used in clinical and forensic toxicology applications.

The present work describes the development and analytical validation of a method involving microextraction packed sorbent and gas chromatography coupled to mass spectrometry (MEPS-GC-MS) for the multi-residue analysis of 22 pesticides (permethrin, fenpropathrin, aldrin, α-hexachlorocyclohexane, β-hexachlorocyclohexane, lindane, vinclozolin, endosulfan, heptaclor, dodecaclor, tetradifon, 1,1-dichloro-2,2-bis (p-chlorophenyl)ethane, 1,1-bis(p-chlorophenyl)-2,2-dichloroethylen, carbofuran, carbaryl, pirimiphos methyl, chlorpyriphos, dimethoate, disulfoton, fenamiphos, terbufos and profenofos) in honey samples. The MEPS variables of sample pH, draw-eject cycles, ionic strength and desorption procedure were optimized to improve the sensitivity of the proposed method. The method was shown to be linear at concentrations ranging from 2, 5 and 10 ng/g (limit of quantification) to 75-100 ng/g. These values are lower than those established as the maximum residue limits for honey samples. The accuracy values (82-114%) were adequate for all the analytes, as were the inter-day precision data, with coefficient of variation lower than 14%. On the basis of analytical validation, the MEPS-GC methodology has been shown to be a promising alternative for the analysis of pesticides in honey samples. The MEPS packed syringe can be reused 40 times for honey samples, whereas the conventional solid-phase extraction (SPE) column can only be used once. Compared with liquid-liquid extraction and SPE, MEPS is able to reduce sample preparation time and organic solvent consumption.

& Rapid and sensitive analytical method for the simultaneous determination of sulfonamides (sulfacetamide, sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxypyridazine, and sulfamethoxazole) in poultry litter wastewater samples by microextraction packed sorbent (C8) and liquid chromatography with spectrophotometric detection (MEPS=LC) analysis. We evaluated how MEPS variables, such as the pH extraction, draw-eject cycles, ionic strength, and desorption conditions (solvent and solvent volume) affected extraction performance, to obtain a more efficient extraction process in the proposed method. The proposed MEPS=LC method presented linear range at concentrations from 5.0 ng mL À1 (Limit of quantification -LOQ) to 200 ng mL À1 , inter-day precision with coefficient of variation lower than 8%, correlation coefficient greater than 0.998; the extraction phase C8 was used. On the basis of analytical validation, the MEPS=LC methodology can be used to analyze sulfonamides in poultry litter wastewater samples.

O presente trabalho descreve a aplicação bem sucedida da microextração em sorvente empacotado e cromatografia líquida com detecção de arranjo de diodos (MEPS/LC-DAD) para a determinação simultânea das sulfonamidas (sulfacetamida, sulfadiazina, sulfatiazol, sulfametazina sulfametoxipiridazina e sulfametoxazol) em amostras de ovos. As variáveis MEPS (pH da amostra, número de ciclos aspirar/dispensar, força iônica e procedimento de dessorção) foram otimizados para aumentar a sensibilidade analítica do método. O método apresentou linearidade na faixa de concentração de 30 ng g -1 (limite de quantificação, LOQ) a 300 ng g -1. Este valor de LOQ é inferior ao limite máximo de resíduo (LMR) preconizado para sulfonamidas em amostras de ovos (100 µg kg -1 ). As taxas de recuperação foram adequadas para todos os analitos (> 94%), bem como os dados de precisão inter-ensaio, com coeficientes de variação inferiores a 10%. Com base na validação analítica, a metodologia MEPS/LC é adequada para a determinação de sulfonamidas em amostras de ovos.The present work describes a successful application of microextraction packed sorbent and liquid chromatography with diode array detection (MEPS/LC-DAD) for simultaneous determination of the sulfonamides (sulfacetamide, sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxypiridazine and sulfamethoxazole) in egg samples. The MEPS variables (pH of the sample, draw-eject cycles, ionic strength, and desorption procedure) were optimized, in order to improve the sensitivity of the proposed method. The method was shown to be linear at concentrations ranging from 30 ng g -1 (limit of quantification, LOQ) to 300 ng g -1 . This LOQ value is lower than those established as the maximum residue limit (MRL) for egg samples (100 µg kg -1 ). The accuracy values were adequate for all analytes (> 94%), as well as the inter-day precision data, with coefficient of variation lower than 10%. On the basis of analytical validation, the MEPS/LC methodology has been shown to be a promising alternative for analysis of sulfonamides in egg samples. Keywords: MEPS, sulfonamides, liquid chromatography, egg IntroductionSulfonamides (SAs) are a group of synthetic antibiotics that have played an important role as effective chemotherapeutics in bacterial and protozoan infections in veterinary medicine practice. Subtherapeutic doses of more than ten SAs are routinely used in food-producing animals for prophylactic and growth-promoting purposes. SAs residues could be potentially toxic to aquatic organisms and humans because of their carcinogenic potency and possible antibiotic resistance. [1][2][3][4] There are no sulfonamides approved for use in laying hens. The use of veterinary drugs for medicinal purposes in laying hens could result in violative drug residues in food meant for human consumption. Of all the marketed SAs, only sulfamethazine and sulfadimethoxine have been approved for use in chickens. Furthermore, this approval extends to broilers only, not laying hens. 4,5 To safeguard human health, many countries ...

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A multicommuted method for determination of chlorine in water samples using a 100-cm cell was developed. In this method, orto-Tolidine reacts with chlorine and the product was monitored at 438 nm. The analytical curve for chlorine was linear in concentration range from 1.34x10 -6 to 2.01x10 -5 mol L -1 with a detection limit of 9.40x10 -8 mol L -1 . A sampling rate of 45 h -1 and a RSD of 1.0 % (n = 15) were obtained. The method was applied with success for chlorine determination in six water samples.