固相萃取-超高效液相色谱-串联质谱法测定乳粉和果冻中的氯化胆碱

建立了固相萃取-超高效液相色谱-串联质谱测定乳粉和果冻中氯化胆碱的分析方法。样品在10 mL 0.02mol/L乙酸铵溶液(冰乙酸调节pH至3.0)中水解3 h后离心,上清液经DIKMA ProElut PLS固相萃取柱(60 mg/3 mL)净化后,用Agilent ZORBAX 300 SCX色谱柱(150 mm×2.1 mm,5μm)进行分离,通过电喷雾正离子(ESI~+)模式电离,多反应监测(MRM)模式进行定性和定量分析。方法的检出限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.15 mg/kg和0.50 mg/kg,加标回收率为70.8%~100.2%,相对标准偏差(RSD)均不大于6.83%(n=6)。目标化合物在0.05~8.0 mg/L范围内线性关系良好,线性方程为Y=2.05×10~5X+3.24×10~4,相关系数(r)为0.996。对市售乳粉和果冻中的氯化胆碱进行检测,结果表明,乳粉和果冻中氯化胆碱的含量分别为251.0~2 448 mg/kg和0.261~0.314 mg/kg。该法准确可靠、灵敏度高,适用于乳粉和果冻中氯化胆碱的测定。

Determination of choline chloride in milk powder and jelly by solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry

An analytical method was developed for the determination of choline chloride in milk powder and jelly by solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were centrifuged after hydrolyzation 3 h in 10 mL 0.02 mol/L ammonium acetate (glacial acetic acid adjust pH to 3.0). The supernatant was cleaned up by a DIKMA ProElut PLS column (60 mg/3 mL). The target compounds were separated by an Agilent ZORBAX 300 SCX column (150 mm×2.1 mm, 5 μm). Qualitative and quantitative analyses were carried out by multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI⁺). The limit of detection (LOD, S/N=3) and the limit of quantitation (LOQ, S/N=10) were 0.15 mg/kg and 0.50 mg/kg, respectively. The recoveries of choline chloride spiked in milk powder and jelly were 70.8%-100.2%, with RSDs no more than 6.83% (n=6). The standard curves showed good linearity in the concentration range from 0.05 to 8.0 mg/L with correlation coefficient (r) of 0.996. The method was applied to detection of commercially available choline chloride in milk powder and jelly. The contents of choline chloride in real milk power and jelly samples were 251.0-2448 mg/kg and 0.261-0.314 mg/kg, respectively. The developed method is accurate, reliable, sensitive, and suitable for the determination of choline chloride in milk powder and jelly.