Bee pollen is a major substrate for mycotoxins growth when no prompt and adequate drying is performed by the beekeeper after collection by bees. Regulatory limits for aflatoxins and ochratoxin A are currently in force in the European Union for a rising list of foodstuffs, but not for this. An immunoaffinity column cleanup process has been applied prior to the analysis of aflatoxins B(1), B(2), G(1), and G(2) and ochratoxin A (OTA). Optimization of the HPLC conditions has involved both a gradient elution and a wavelength program for the separation and fluorimetric quantitation of all five mycotoxins at their maximum excitation and emission values of wavelength in a single run. The higher limit of detection (mug/kg) was 0.49 for OTA and 0.20 for aflatoxin B(1). Repeatability (RSDr) at the lower limit tested ranged from 9.85% for OTA to 6.23% for aflatoxin G(2), and recoveries also at the lower spiked level were 73% for OTA and 81% for aflatoxin B(1). None of the 20 samples assayed showed quantifiable values for the five mycotoxins.
Melatonina, tirosol e hidroxitirosol son sustancias bioactivas cuya presencia se ha descrito en el vino en baja concentración, lo que representa un reto para su análisis. El presente trabajo plantea la puesta a punto de un método para su determinación, mediante cromatografía líquida de alta eficacia acoplada a detección por espectrofotometría de diodos y espectrometría de masas (HPLC-DAD-MS) y su aplicación posterior para su análisis en muestras de diversos tipos de vinos.
Flavonoids are one of the largest groups of plant secondary metabolites. They comprise several thousand compounds that share a phenylchromane skeleton and can be classified into different classes, namely flavones, flavonols, flavanones, flavanols, anthocyanins, dihydroflavonols, isoflavones, and chalcones. Flavonoids occur in their natural sources as aglycones or glycosylated forms and as monomers or constituting polymerized structures and can be found both as free and matrix‐bound compounds. This structural diversity affects their physicochemical behavior, and different flavonoid classes and compounds may have different requisites for their extraction and analysis, so that there is not a unique analytical strategy that applies in all situations. In this article, the main methodological approaches to the analysis of flavonoids in plant materials are revised. Particular attention is paid to more recent extraction techniques and high‐performance liquid chromatography (LC)‐based methodologies coupled to different detection systems, and especially liquid chromatography coupled to mass spectrometry (LC‐MS) that currently dominates the field of flavonoid analysis.
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