高效液相色谱-高分辨质谱法测定奶粉及保健品食品中的左旋肉碱

Determination of L-carnitine in milk powder and healthy food by high performance liquid chromatography coupled with high resolution mass spectrometry

中文关键词:  高效液相色谱-高分辨质谱法  左旋肉碱  同位素内标法  奶粉及保健食品

英文关键词:high performance liquid chromatography-mass spectrometry  L-carnitine  isotope internal standard method  milk powder and healthy food

中文摘要:

      目的 建立高效液相色谱-高分辨质谱法测定奶粉及保健食品中左旋肉碱的含量。方法 奶粉及保健食品样品经适量40 ℃水溶解后, 加乙酸锌沉淀蛋白, 待样品冷却至室温后用水定容至50 mL, 并超声提取 30 min。在4 ℃条件下, 待测溶液经8000 r/min的速度离心3 min, 取上清液过0.45 μm水相滤膜。经质谱正离子模式测定, 同位素内标法定量。结果 左旋肉碱0.1~4.0 μg/mL范围内呈良好线性关系, 相关系数为1.0000, 方法检出限为0.1 μg/kg, 定量限为0.2 μg/kg。加标回收率为98%~110%, 相对标准偏差为0.2%~0.5%。对奶粉质控样品进行测定, 结果与证书结果一致。结论 该法前处理简单、测定快速、准确度高, 灵敏度好, 适用于奶粉及保健食品中左旋肉碱的快速分析检测。

英文摘要:

      Objective To establish a method for determination of L-carnitine in milk powder and healthy food by high performance liquid chromatography coupled with high resolution mass spectrometry. Methods The milk powder samples and healthy food samples were dissolved by appropriate amount of water at 40 ℃, precipitated with zinc acetate, and diluted to 50 mL when the samples were cooled to the room temperature, and conducted for 30 min by ultrasonic extraction. The solution was centrifuged at 8000 r/min for 3 min at 4 ℃, and the supernatant was filtered through a 0.45 μm aqueous phase membrane, measured by mass spectrometry in positive ion mode, and quantified by isotope internal standard method. Results L-carnitine showed a good linear relationship in the range of 0.1–4.0 μg/mL, the correlation coefficient was 1.0000, the limit of detection the method was 0.1 μg/kg, and the limit of quantification was 0.2 μg/kg. The standard recoveries were 98%–110%, and the relative standard deviations were 0.2%–0.5%. The quality control sample of milk powder was determined and the result was consistent with the certificate. Concusion The method has simple pretreatment, rapid determination, high accuracy and good sensitivity, and it is suitable for the rapid analysis and detection of L-carnitine in milk powder and health food.