Neste artigo, duas bebidas mexicanas com denominação de origem controlada (DOC), tequila e mezcal, foram facilmente discriminadas por espectrofotometria UV-Vis e métodos quimiométricos. Os espectros foram registrados na faixa de 250-400 nm; a principal característica foi uma banda larga centrada em torno de 280 nm, cuja amplitude varia segundo o tipo de bebida e de marca. No entanto, diferenças adicionais foram identificadas através de análise multivariada, mostrando uma distinção clara entre as bebidas. Usando RP-HPLC com detector ultravioleta, os compostos que têm origem na banda de absorção foram determinados. Portanto, o espectro de cada bebida na faixa de comprimento de onda de 250-330 nm aproximadamente, mostrou uma mistura particular de furfural (FUR), 2-acetilfurano (2AF) e 5 methylfurfural (5MF). Além disso, os espectros de absorção das misturas de FUR, 2AF e 5MF foram registrados em diferentes concentrações e com um modelo de mínimos quadrados parciais (PLS), as concentrações desses compostos foram previstas em amostras de teste e em licores. Quando estes resultados foram comparados com os obtidos por HPLC, os coeficientes de correlação foram de R ≥ 0,920. Portanto, esta metodologia apresenta um método alternativo para identificar e quantificar alguns compostos furanos em tequilas brancas e mezcales. Além destes resultados, a metodologia pode ser realizada in situ e resultados específicos no controle de qualidade podem ser obtidos em poucos minutos.In this paper, two Mexican white spirits with appellation d'origen contrôlée (AOC), i.e., tequila and mezcal were easily discriminated by using UV-Vis spectrophotometry and chemometric techniques. The spectra were recorded in the range of 250-400 nm and their main feature is a broad band centered about 280 nm whose amplitude changes according to the type of beverage and brand, however, additional differences are pointed out through multivariate analysis that makes a fair differentiation between the beverages. By using RP-HPLC with UV detector, the compounds that originate the absorption band were determined. Thus, the spectrum of each beverage in the wavelength range of 250-330 nm, approximately, is a particular mixture of furfural (FUR), 2-acetylfuran (2AF) and 5-methylfurfural (5MF). Further, the absorption spectra of mixtures of FUR, 2AF and 5MF standards were recorded at several concentrations and by using a partial least square model (PLS), the concentrations of those compounds were predicted in test and spirit samples. When these results were compared to those obtained by HPLC, the correlation coefficients were R ≥ 0.920. Therefore, with this methodology one builds up an alternative method to identify and quantify some furanic compounds in white tequilas and mezcals. In addition to these results, the methodology can be performed on site and results about specific quality controls can be obtained within minutes.
Next generation β-glucuronidases can effectively cleave glucuronides in urine at room temperature. However, during the discovery studies, additional challenges were identified for urine drug testing across biologically relevant pH extremes and patient urine specimens. Different enzymes were evaluated across clinical urine specimens and commercially available urine control matrices. Each enzyme shows distinct substrate preferences, pH optima, and variability across clinical specimens. These results demonstrate how reliance on a single glucuronidated substrate as the internal hydrolysis control cannot ensure performance across a broader panel of analytes. Moreover, sample specific urine properties compromise β-glucuronidases to varying levels, more pronounced for some enzymes, and thereby lower the recovery of some drug analytes in an enzyme-specific manner. A minimum of 3-fold dilution of urine with buffer yields measurable improvements in achieving target pH and reducing the impact of endogenous compounds on enzyme performance. After subjecting the enzymes to pH extremes and compromising chemicals, one particular β-glucuronidase was identified that addressed many of these challenges and greatly lower the risk of failed hydrolyses. In summary, we present strategies to evaluate glucuronidases that aid in higher accuracy urine drug tests with lower potential for false negatives.
Novel opioid interferences were observed during the development of a high-resolution liquid chromatography-mass spectrometry urine drug testing method for 47 analytes from multiple drug classes. The interferences affected both analytes and internal standards and were only observed when the method was challenged with patient samples. Some interferences were attributable to isomeric opioid metabolites not previously reported while others were due to interference from in-source dissociations or 13C isotopic contributions from known opioid metabolites not typically monitored as analytes. Based on patient drug profiles, known and inferred metabolism, accurate mass, retention time and MS/MS spectrum, the putative identity of each interference was assigned and later confirmed, when possible, using an authentic standard. Opioids are some of the most frequently monitored analytes in urine drug testing laboratories. Because of the potential for co-purification, co-chromatography and spectral similarity, it is anticipated that the reported opioid metabolite interferences could be present with other method conditions and instrument platforms. The objectives of this work are to raise awareness of these interferences and emphasize the importance of evaluating patient samples for potential interferences during method development.
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