RESUMEN
The sorbate and benzoate contents of commercial fresh cheese (quarg) samples are determined by reverse-phase liquid chromatography following extraction with a methanol-acetate buffer pH 4.5 mixture (37 + 63). The mobile phase is acetonitrile-acetate buffer pH 4.5 (20 + 80), the effluent flow rate is maintained at 1.0 mL/min, and the detector is set at 232 nm. Recoveries from quarg spiked at the 5-50 mg/kg level ranged from 95 to 99%, which compares favorably with methods previously published. Precision averaged 2-5% RSD, whereas the limit of detection was 0.3 mg/kg (sorbic acid) and 1.0 mg/kg (benzoic acid).
Asunto(s)
Benzoatos/análisis , Queso/análisis , Ácidos Grasos Insaturados/análisis , Ácido Sórbico/análisis , Tampones (Química) , Cromatografía Liquida , Francia , Indicadores y Reactivos , Espectrofotometría UltravioletaRESUMEN
Furfural (2-furaldehyde) and hydroxymethylfurfural (5-hydroxy-2-furaldehyde, HMF) are determined in brandy and honey by reverse phase high performance liquid chromatography. Brandies and other spirits are injected without sample preparation; honey is diluted with water and the solution is filtered before injection onto a reverse phase column with detection at 285 nm. The mobile phase is methanol--water (10 + 90) and the effluent flow rate is maintained at 1.0 mL/min. External standardization is used for quantitative determination. Recoveries from cognac and honey spiked at different levels ranged from 95 to 99% (furfural) and 95 to 100% (HMF). The furfural content of the brandies was also determined by the existing colorimetric method of the Bureau National Interprofessionel du Cognac. The HMF content of the honey was correlated to the results of the classic method of Winkler.
Asunto(s)
Bebidas Alcohólicas/análisis , Furaldehído/análogos & derivados , Furaldehído/análisis , Miel/análisis , Cromatografía Líquida de Alta Presión/métodos , Contaminación de Alimentos/análisisRESUMEN
An interlaboratory procedure for the quantitative extraction and analysis of thebaine from different tissues of Papaver bracteatum Lindl. is presented. Each step was evalutated for the yield of thebaine by use of 1-3H-thebaine and GLC. The method of drying and milling of tissue and the size of resultant particles were important factors in the quantitative recovery of thebaine.