Multimycotoxin Determination in Grains: A Comprehensive Study on Method Validation and Assessment of Effectiveness of Controlled Atmosphere Storage in Preventing Mycotoxin Contamination.

Two simple and low-cost QuEChERS approaches were optimized and validated for multimycotoxin determination in grains by UPLC-MS/MS and applied to assess effectiveness of controlled atmosphere (CA) storage in preventing mycotoxin contamination. Common bean, soybean, and maize samples were stored for 6 months. CA treatments were conducted varying O2 and CO2 partial pressures, temperatures, and moisture contents of the chambers. In the validation study for common bean and maize, 8 out of 11 mycotoxins were successfully validated. For soybean, 10 out of 11 mycotoxins were validated. Aflatoxin B1 was detected in all commodities. Statistical tests suggest that storage temperature played a key role in aflatoxin B1 concentrations in common bean and soybean, but had no influence on maize. Maize was also positive for fumonisins B1 and B2. Differences in fumonisin concentrations were not significant among different treatments. Concentrations of aflatoxin B1 in some samples exceeded legislation's maximum levels. Thus, some of the CA treatments applied were effective in preventing mycotoxin contamination in common bean and soybean but were not effective for maize.

Mycotoxins in wheat flour: occurrence and co-occurrence assessment in samples from Southern Brazil.

The goal of this survey was to evaluate the presence and concentration as well as the co-occurrence of legislated and non-legislated mycotoxins in wheat flour samples from Brazil. A total of 200 wheat flour samples were analysed by a validated multi-mycotoxins method. DON was the mycotoxin with the highest occurrence, being present in 100% of the analysed samples and showing contamination in both years and regions (53-2905 µg kg-1). ZEN was detected in 51% (

Simultaneous determination of 117 pesticides and 30 mycotoxins in raw coffee, without clean-up, by LC-ESI-MS/MS analysis.

This paper describes the optimization and validation of an acetonitrile based method for simultaneous extraction of multiple pesticides and mycotoxins from raw coffee beans followed by LC-ESI-MS/MS determination. Before extraction, the raw coffee samples were milled and then slurried with water. The slurried samples were spiked with two separate standard solutions, one containing 131 pesticides and a second with 35 mycotoxins, which were divided into 3 groups of different relative concentration levels. Optimization of the QuEChERS approach included performance tests with acetonitrile acidified with acetic acid or formic acid, with or without buffer and with or without clean-up of the extracts before LC-ESI-MS/MS analysis. For the clean-up step, seven d-SPE sorbents and their various mixtures were evaluated. After method optimization a complete validation study was carried out to ensure adequate performance of the extraction and chromatographic methods. The samples were spiked at 3 concentrations levels with both mycotoxins and pesticides (with 6 replicates at each level, n = 6) and then submitted to the extraction procedure. Before LC-ESI-MS/MS analysis, the acetonitrile extracts were diluted 2-fold with methanol, in order to improve the chromatographic performance of the early-eluting polar analytes. Calibration standard solutions were prepared in organic solvent and in blank coffee extract at 7 concentration levels and analyzed 6 times each. The method was assessed for accuracy (recovery %), precision (RSD%), selectivity, linearity (r2), limit of quantification (LOQ) and matrix effects (%).

Enantioselective metabolism of hydroxychloroquine employing rats and mice hepatic microsomes / Metabolismo enantiosseletiva da hidroxicloroquina empregando microssomas hepáticos de ratos e camundongos

Hydroxychloroquine (HCQ) is an important chiral drug used, mainly, in the treatment of rheumatoid arthritis, systemic lupus erythematosus and malaria, and whose pharmacokinetic and pharmacodynamic properties look to be stereoselective. Respecting the pharmacokinetic properties, some previous studies indicate that the stereoselectivity could express itself in the processes of metabolism, distribution and excretion and that the stereoselective metabolism looks to be a function of the studied species. So, the in vitro metabolism of HCQ was investigated using hepatic microsomes of rats and mice. The microsomal fraction of livers of Wistar rats and Balb-C mice was separated by ultracentrifugation and 500 μL were incubated for 180 minutes with 10 μL of racemic HCQ 1000 μg mL-1. Two stereospecific analytical methods, high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), were used to separate and quantify the formed metabolites. It was verified that the main formed metabolite is the (-)-(R)-desethyl hydroxychloroquine for both animal species.

A hidroxicloroquina (HCQ) é um importante fármaco quiral usado, principalmente, no tratamento de artrite reumatóide, lupus eritematoso sistêmico e malária e cujas propriedades farmacocinéticas e farmacodinâmicas parecem ser estereosseletivas. Em relação às propriedades farmacocinéticas, alguns estudos prévios indicam que a estereosseletividade pode se expressar nos processos de metabolismo, distribuição e excreção e que o metabolismo estereosseletivo parece ser função da espécie estudada. Sendo assim, o metabolismo in vitro da HCQ foi investigado usando microssomas de fígado de ratos e de camundongos. A fração microssômica de fígados de ratos Wistar e de camundongos Balb-C foi isolada por ultracentrifugação e 500 μL foram incubados por 180 minutos com 10 μL de HCQ racêmica 1000 μg mL-1. Dois métodos analíticos estereoespecíficos, por cromatografia líquida de alta eficiência (HPLC) e eletroforese capilar (CE), foram usados para separar e quantificar os metabólitos formados. Verificou-se que o principal metabólito formado é o (-)-(R)-desetilidroxicloroquina para ambas as espécies de animais.

Enantioselective analysis of the metabolites of hydroxychloroquine and application to an in vitro metabolic study.

A one-step chiral method for the quantification of the enantiomers of two hydroxychloroquine (HCQ) metabolites, desethylchloroquine (DCQ) and desethylhydroxychloroquine (DHCQ) by HPLC is described, in addition to its application to the in vitro study of HCQ metabolism in rat liver microsomes. Liquid-liquid extraction was used to extract the enantiomers from microsome samples and the separation was performed on a Chiralpak AD-RH column protected with an RP-8 guard column using hexane:isopropanol (92:8, v/v) plus 0.1% diethylamine as the mobile phase, at a flow rate of 1.0 mL min(-1). The detection was carried out at 343 nm. The method proved to be linear in the range of 50-5000 ng mL(-1) for DCQ enantiomers and 125-2500ngmL(-1) for DHCQ enantiomers, with a quantification limit of 50 and 125 ng mL(-1), respectively. Precision and accuracy, demonstrated by within-day and between-day assays, were lower than 15%. The metabolic study demonstrated that metabolism is stereoselective for HCQ. The major metabolites formed in the incubation of racemic HCQ were (-)-(R)-DCQ and (-)-(R)-DHCQ with R/S ratios of 2.2 and 3.3, respectively.