柱前衍生-高效液相色谱-荧光检测法测定罐头食品中的尿素

建立了罐头食品中尿素残留检测的柱前衍生-高效液相色谱-荧光检测方法。取5.0 g样品,经20 mL 1%(v/v)乙酸溶液提取、定容,离心后取上清液过滤,吸取0.5 mL提取液用呫吨醇进行衍生,采用高效液相色谱-荧光检测器进行测定。尿素在0.1~500 mg/L内线性良好,相关系数大于0.999 5。实验表明,在5种罐头食品中各添加0.001~30 g/kg尿素,其平均回收率为80.2%~109.7%,相对标准偏差(n=6)为2.05%~6.53%,检出限为0.5mg/kg,定量限为1.0 mg/kg。利用本研究建立的方法对168个实际样品进行测定,在3个肉类罐头样品中检出尿素,含量分别为10.6、62.1和2.6 mg/kg。方法稳定、可靠、操作简单,适用于罐头食品中尿素的检测。

Determination of urea in canned foods by high performance liquid chromatography-fluorescence detection coupled with precolumn derivatization

A method for the determination of urea residue in canned foods by high performance liquid chromatography-fluorescence detection (HPLC-FLD) coupled with precolumn derivatization was established. The sample (5.0 g), including canned edible fungi, fruit, vegetable, fish, and meat was extracted with 20 mL 1%(v/v) acetic acid solution. The extract was centrifuged, filtrated, and then derivatized with xanthydrol. The analysis was completed with HPLC-FLD. A good linear relationship was obtained in the range of 0.1-500 mg/L with the correlation coefficients more than 0.9995. The average recoveries of urea spiked at 0.001-30 g/kg levels in five kinds of canned foods ranged from 80.2% to 109.7% with the RSDs of 2.05%-6.53%. The limit of detection (LOD) was 0.5 mg/kg, and the limit of quantitation (LOQ) was 1.0 mg/kg. The proposed procedure was then applied to the analysis of 168 real samples collected from Xiamen, Fujian Province, China. The existence of urea was found in three pork cans with contents of 10.6, 62.1 and 2.6 mg/kg, respectively. The method is stable, reliable, simple and suitable for the determination of urea in canned foods, and has great potential for routine analysis in foodstuffs.