Los compuestos polifenólicos en productos apícolas y su función antioxidante

Peer reviewe

Fenugreek seeds: phenolic composition and antioxidant activity

Trabajo presentado a la XXV International Conference On Polyphenols (ICP), celebrada en Francia en agosto de 2010.Peer reviewe

Improved sample preparation for GC-MS-SIM analysis of ethyl carbamate in wine.

AbstractAn improved sample preparation procedure for analysis of carcinogenic ethyl carbamate (EC) in wine by GC–MS–SIM is proposed. Differences over AOAC reference procedure were: (1) use of EC-d5 as internal standard instead of less similar propyl carbamate; (2) extraction by diethyl ether instead of more toxic dichloromethane, and (3) concentration by vacuum automated parallel evaporation instead of more time and work consuming rotary evaporation. Mean recovery was 104.4%, intraday precision was 6.7% (3.4μgL−1) and 1.7% (88.5μgL−1), regression coefficient was 0.999 in the linear working range of 3–89μgL−1, and limits of detection and quantification were 0.4 and 1.2μgL−1. Applicability was demonstrated by analysis (in triplicate) of 5 wine samples. EC concentration ranged from 5.2±0.2 to 29.4±1.5μgL−1. The analytical method is selective, accurate, repeatable, linear, and has similar method performance as the reference method along with the several mentioned advantages

Rapid and sensitive methodology for determination of ethyl carbamate in fortified wines using microextraction by packed sorbent and gas chromatography with mass spectrometric detection

This work presents a new methodology to quantify ethyl carbamate (EC) in fortified wines. The presented approach combines the microextraction by packed sorbent (MEPS), using a hand-held automated analytical syringe, with one-dimensional gas chromatography coupled with mass spectrometry detection (GC–MS). The performance of different MEPS sorbent materials was tested, namely SIL, C2, C8, C18, and M1. Also, several extraction solvents and the matrix effect were evaluated. Experimental data showed that C8 and dichloromethane were the best sorbent/solvent pair to extract EC. Concerning solvent and sample volumes optimization used in MEPS extraction an experimental design (DoE) was carried out. The best extraction yield was achieved passing 300 μL of sample and 100 μL of dichloromethane. The method validation was performed using a matrix-matched calibration using both sweet and dry fortified wines, to minimize the matrix effect. The proposed methodology presented good linearity (R2 = 0.9999) and high sensitivity, with quite low limits of detection (LOD) and quantification (LOQ), 1.5 μg L−1 and 4.5 μg L−1, respectively. The recoveries varied between 97% and 106%, while the method precision (repeatability and reproducibility) was lower than 7%. The applicability of the methodology was confirmed through the analysis of 16 fortified wines, with values ranging between 7.3 and 206 μg L−1. All chromatograms showed good peak resolution, confirming its selectivity. The developed MEPS/GC–MS methodology arises as an important tool to quantify EC in fortified wines, combining efficiency and effectiveness, with simpler, faster and affordable analytical procedures that provide great sensitivity without using sophisticated and expensive equipment