柱前衍生高效液相色谱-质谱法测定水稻中尼克烟酰胺含量

Determination of Nicotinamide in Rice by Pre-column Derivatization and High Performance Liquid Chromatography-Mass Spectrometry

建立了柱前衍生高效液相色谱-质谱联用(HPLC-MS)测定水稻中尼克烟酰胺含量的方法。样品中尼克烟酰胺经水提取后,与9-芴甲基氯甲酸酯(FMOC-Cl)衍生,采用液相色谱质谱联用仪测定。系统研究了衍生剂浓度和衍生介质等条件对衍生效率的影响。通过优化流动相酸度和梯度洗脱等条件,提高了方法灵敏度。尼克烟酰胺在0.1～5.0mg/L范围内呈良好的线性关系(r=0.9983),对水稻的根、茎、叶及大米的标准加入实验表明,方法的添加回收率在72.0%～89.2%之间;相对标准偏差为2.3%～9.6%;方法检出限为0.05mg/kg。方法简便、准确可靠,可以满足水稻中生理水平尼克烟酰胺的定性定量分析。

A method was developed for the determination of nicotinamide （NA） in rice by pre-column derivatization and high performance liquid chromatography/electrospray ionization mass spectrometry （HPLC/ESI- MS）. After extraction with water, NA was derivatized by 9-fluorenylmethoxyearbonyl（FMOC-CI）. In order to enhance the sensitivity, the derivatization was optimized regarding organic solvent content and amount of FMOC-Cl. The best HPLC conditions for the separation of NA in real samples were achieved using a C18 column and mobile phase which contained 0. 1% formic acid. The MS experiments were performed in selected ion monitoring mode（SIM）. The method shows good linearity over the range of 0. 1 -5 mg,/L for NA with a correlation coefficient of 0. 9983. The limit of determination（LOD） was 0.05 mg/kg. Precision and recovery studies were evaluated at three concentration levels for rice root, stem, leaf and unpolished rice. The recovery （ n = 5） ranged from 72.0% to 89.2% with relative standard deviations from 2.3% to 9.6%. The method is simple, highly selective and reliable, and can be used to determine NA in rice at physiological level.