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目的建立测定婴幼儿配方奶粉中D/L-肉碱含量的高效液相色谱-二极管阵列法和荧光法。方法样品以20%乙醇为提取溶剂,L-丙氨酸-β-萘胺与样品中肉碱反应,反应衍生物通过流动相在C18色谱柱中分离,二极管阵列法采用50 mmol/L p H2.7磷酸二氢钠缓冲液∶乙腈-四氢呋喃(体积比91∶9)为流动相,在紫外波长为244 nm处进行检测。荧光法采用(50 mmol/L p H2.7)磷酸二氢钾缓冲液∶乙腈-四氢呋喃(体积比85∶8∶7)为流动相,在荧光激发波长为280 nm和发射波长为328 nm处,进行检测。结果二极管阵列法中L-肉碱回收率在73%~96%,RSD在3.91%~7.08%;D-肉碱回收率在80%~94%,RSD在4.36%~8.89%。荧光法中L-肉碱回收率在84%~104%,RSD在4.5%~7.0%;D-肉碱回收率在85%~100%,RSD在3.6%~6.2%。结论以上2种方法均适用于婴幼儿配方食品中D/L-肉碱的测定,测定结果差异均无统计学意义(P>0.05)。但荧光法的检出灵敏度高,更适合婴幼儿配方食品中较低含量的D/L-肉碱检测。
OBJECTIVE To establish a high performance liquid chromatography-diode array and fluorescence method for the determination of D / L-carnitine in infant formula. Methods The sample was extracted with 20% ethanol and L-alanine-β-naphthylamine was reacted with carnitine in the sample. The reactive derivative was separated on a C18 column by mobile phase. The diode array method was used with 50 mmol / L p H2 .7 sodium dihydrogen phosphate buffer: acetonitrile-tetrahydrofuran (91: 9 by volume) as the mobile phase, detected at UV wavelength of 244 nm. Fluorescence method was performed with 50 mmol / L p H2.7 potassium dihydrogen phosphate buffer: acetonitrile-tetrahydrofuran (85: 8: 7 by volume) as the mobile phase at a fluorescence excitation wavelength of 280 nm and an emission wavelength of 328 nm , For testing. Results The results showed that the recovery rate of L-carnitine was 73% ~ 96% and the RSD was 3.91% ~ 7.08%. The D-carnitine recovery was 80% ~ 94% and RSD was 4.36% ~ 8.89%. The recovery of L-carnitine was 84% ~ 104% and the RSD was 4.5% ~ 7.0%. The recovery of D-carnitine was 85% ~ 100% and RSD was 3.6% ~ 6.2%. Conclusion The above two methods are suitable for the determination of D / L-carnitine in infant formula, the results were not statistically different (P> 0.05). However, the fluorescence detection of high sensitivity, more suitable for infant formula in the lower content of D / L-carnitine detection.