Chromatographic determination of riboflavin in the presence of tetracyclines in skimmed and full cream milk using fluorescence detection

Abstract

Foi estabelecido um método cromatográfico rápido e simples para a determinação de riboflavina em leite bovino, na presença de tetraciclinas. Para tanto, as proteínas foram precipitadas com ácido tricloroacético e a separação realizada por CLAE em fase reversa com detector de fluorescência. Foi utilizada uma coluna C 8 com eluição isocrática e fase móvel acetato de sódio 0,1 mol L-1 , cloreto de cálcio 35 mmol L-1 , EDTA 25 mmol L-1 : metanol (65:35 v/v). O método foi validado mediante avaliação dos seguintes parâmetros: linearidade (0,9980), faixa linear (0,50 a 1,30 μg mL-1), precisão intra e inter-ensaio (RSD ≤ 0,5%), exatidão (recuperação 92%) e limites de detecção e de quantificação (0,75 μg mL-1 e 0,22 μg mL-1 , respectivamente). O método foi aplicado na análise de leite integral e desnatado, mostrando-se robusto na presença de substâncias fluorescentes como as tetraciclinas, e quando comparado com o método espectrofluorimétrico, não revelou diferença significativa (p≤ 0,05) entre os resultados obtidos. An easy and simple chromatographic method for the determination of riboflavin in bovine milk in the presence of tetracyclines was established. For this, the proteins were precipitated with trichloroacetic acid and the separation was carried out by reversed-phase HPLC with fluorescence detection. A C 8 column was used with isocratic flow using a mobile phase consisting of 0.1 mol L-1 sodium acetate, 35 mmol L-1 calcium chloride and 25 mmol L-1 EDTA : methanol (65:35 v/v). The method was validated by means of the following parameters: linearity (0.9980), linear range (0.50-1.30 µg mL-1), intra-and inter-assay precision (RSD ≤ 0.5%), accuracy (recovery 92%), and detection and quantitation limits (0.75 μg mL-1 and 0.22 μg mL-1 , respectively). The method was applied for analysis of full cream and skimmed milk, showing robustness in the presence of tetracyclines, and when compared with a spectrofluorimetric method showed no significant difference (p≤ 0.05) between the results obtained.

Oxidative stability of bovine milk determined by individual variability in herd irrespective of selenium status

“…Tocopherols were extracted and detected as described by Havemose, Weisbjerg, Bredie, and Nielsen (2004), ascorbic acid and uric acid as described by Østdal, Andersen, and Nielsen (2000), and riboflavin as described by Silva, Trevisan, Rath, Poppi, and Reyes (2005). All low molecular weight components were quantified using external standards.…”

Light-induced protein and lipid oxidation in cheese: Dependence on fat content and packaging conditions

“…The samples were injected onto a reverse phase column (Sorbax SB-C8 with the dimension 4.6 × 150 mm, 5 μm from Agilent Technologies, USA). The riboflavin was quantified using fluorescence detection according to Silva et al [29]. Quantification was …”

Does vitamin fortification affect light oxidation in fluid skim milk?

“…Riboflavin Analysis. Riboflavin analysis was conducted in accordance with the procedure published by Silva et al (2005). Briefly, 0.75 mL of 33% trichloroacetic acid (Sigma-Aldrich) was added to 0.5 mL of milk in a 2-mL Eppendorf tube (Sigma-Aldrich).…”