柱前衍生–高效液相色谱法测定白刺果中氨基酸含量

建立一种快速测定不同产地的白刺果中氨基酸含量的HPLC方法。采用柱前邻苯二甲醛(OPA)和氯甲酸芴甲酯(FMOC)联合在线衍生、二元梯度洗脱(流动相A:40 mmol/L NaH2PO4·H2O,pH 7.8;流动相B:乙腈–甲醇–水的体积比为4.5∶4.5∶1)、反相C18短柱分离(色谱柱:Zorbax Eclipse AAA C18柱,75 mm×4.6 mm,3.5μm)、二极管阵列检测器(检测波长:338 nm;参考波长:390 nm)和荧光检测器(激发波长:340 nm;发射波长:450nm)联合检测,内标法定量。各氨基酸含量在4.5~900μmol/L范围内线性关系良好,相关系数为0.991 2~0.999 8,除了蛋氨酸(部分氧化降解)加标回收率为78.1%外,其它各氨基酸的加标回收率为93.1%~105.1%,相对标准偏差为3.21%~6.23%(n=5)。对产自青海、新疆和内蒙古等3个地区的白刺果中氨基酸含量进行了测定,氨基酸总量分别为11.23,10.47,8.84 g/(100 g),并对各种不同类型氨基酸占氨基酸总量的比例进行了分析。该法适合于白刺果氨基酸含量的测定。

Determination of Amino Acid in Nitraria from Different Regions by High Performance Liquid Chromatography with Pre-Column Derivatization

A HPLC method for rapid determination of amino acid in Nitraria from different regions was developed. Online derivatization with o-phthaldialdehyde and 9-fluorenylmethyl chloroformate was performed automatically by the autosampler,and the derivatization was analyzed on a C18 short column （Zorbax Eclipse AAA C18,75 mm×4.6 mm, 3.5μm） using gradient elution （Mobile phase A：40 mmol/L NaH2PO4 · H2O,pH 7.8;Mobile phase B：Acetonitrile-methanol-H2O volume ratio was 4.5∶4.5∶1） with diode array detector （the detection wave length was 338 nm,the reference wave length was 390 nm） and fluorescence detector （the excitation wave length was 340 nm, the emission wave length was 450 nm） combined detection. Quantifications of amino acids were finished by internal standard method. The recoveries of standard spiking of amino acids were in the range of 93.11%-105.34%,except methionine （78.14%）. The relative standard deviations were in the range of 3.21%-6.23%（n=5） . The peak area of amino acids versus their concentration had a good linearity （correlation coefficients were 0.991 2-0.999 8） in the range of 4.5-900 μmol/L. The contents of amino acids in Nitraria from Qinghai,Xinjiang and Inner Mongolia were 11.23,10.47,8.84 g/（100 g） respectively. The ratios of different type amino acids to total content were analyzed. This method is suitable for rapid determination of amino acid in Nitraria.