采用荧光光谱法测定饮料中的苋菜红与亮蓝。样品经柠檬酸溶液调节酸度至pH 6.0,用聚酰胺粉吸附待测物,解析后,以320 nm为激发波长、425 nm为发射波长测定苋菜红,以382 nm为激发波长、445 nm为发射波长测定亮蓝,苋菜红和亮蓝的浓度分别在2.5×10-6~2.50×10-5mol·L-1,5.0×10-6~5.00×10-5mol·L-1范围内与其荧光强度呈线性关系,检出限(3s)分别为2.0×10-7mol·L-1和1.0×10-6mol·L-1。本法用于测定市售饮料中的苋菜红与亮蓝,加标回收率在102%~104%之间,测定值的相对标准偏差均小于5%。

Fluorescent spectrometry was applied to the determination of amaranth and brilliant blue in drink. The acidity of the sample solution was adjusted to pH 6.0 with critic acid solution and the analytes in the solution were adsorbed by polyamide powders. After desorption, amaranth and brilliant blue were determine at the excitation wavelengths of 320 nm , 382 nm and the emission wavelengths of 425 nm, 445 nm, respectively. Linear relationships was found between the fluorescence intensity and the concentrations of amaranth and brilliant blue in the ranges of 2.5×10-6-2.50×10-5mol·L-1 and 5.0×10-6-5.00×10-5mol·L-1, respectively, with detection limits (3s) of 2.0×10-7mol·L-1 and 1.0×10-6mol·L-1, respectively. The proposed method was used to determine amaranth and brilliant blue in the commercially avaliable drink, giving recovery rates obtained by standard addition method in the range of 102%-104% and RSDs less than 5%.