ABSTRACT
A method and evaluated for screening and confirmation of diethylstilbestrol (DES), alpha- and beta-zearalanol in bovine urine was developed. The residues were extracted from urine by C18 cartridges and purified on alumina columns. For screening and confirmation purposes, the anabolic derivatives were analyzed by gas chromatography-mass spectrometry after derivatization with BSTFA + 1% TMCS or a solution of PFPA/acetone (1:2, v/v), respectively. The recovery of most analytes for the whole procedure was higher than 96%, with a detection limit of 0.5 ppb. This procedure is being routinely applied to the Brazilian National Program for the Control of Residues in Meat (PNCRBC).
Subject(s)
Diethylstilbestrol/urine , Estrogens, Non-Steroidal/urine , Zeranol/urine , Aluminum Oxide/chemistry , Animals , Cattle , Diethylstilbestrol/chemistry , Estrogens, Non-Steroidal/chemistry , Gas Chromatography-Mass Spectrometry/methods , Hydrolysis , Reproducibility of Results , Sensitivity and Specificity , Zeranol/chemistryABSTRACT
Synopsis The aim of this work was to evaluate several plant extracts with regard to ultraviolet absorption spectra in view of a possible application as antisolar agents. Liquid and dry extracts of Hamamelis virginiana, Matricaria recutita, Aesculus hippocastanum, Rhamnus purshiana and Cinnamomum zeylanicum were prepared by repercolation, maceration and microwave oven extraction. UVB absorption spectra (290-320nm) were obtained and the solar protection factors (SPF) of these preparations were determined by a spectrophotometric method. The results showed that after incorporation to a 2% solution of the synthetic sunscreen octylmethoxycinnamate, the extracts showed an intensification in SPF values, suggesting that this can be an interesting method to intensify SPF. In addition, these extracts can contribute their emollient and moistening properties to the product. These are important characteristics for protecting skin against exposure to the sun.
