采用全自动氨基酸分析仪测定30批不同产地当归药材中16种氨基酸的含量,结合主成分分析、聚类分析及判别分析评价当归中氨基酸含量的差异及其品质优劣。称取粉碎过筛后的样品1 g,加入0.1 mol·L^-1盐酸溶液30 mL,超声,冷却至室温后,用水定容至100 mL;分取1 mL,于50 ℃真空浓缩至近干,然后加入10 mL样品稀释液(pH 2.20),涡旋溶解,过0.22 μm水系滤膜,按照仪器工作条件测定其中天冬氨酸(Asp)、苏氨酸(Thr)、丝氨酸(Ser)、谷氨酸(Glu)、甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、甲硫氨酸(Met)、异亮氨酸(Ile)、亮氨酸(Leu)、酪氨酸(Tyr)、苯丙氨酸(Phe)、赖氨酸(Lys)、组氨酸(His)、精氨酸(Arg)、脯氨酸(Pro)的含量。结果表明:16种氨基酸标准曲线的线性范围均为1~200 μmol·L^-1,检出限(3S/N)为0.02~0.04 mg·L^-1,加标回收率为90.4%~98.2%,测定值的相对标准偏差(n=6)为1.3%~4.1%;30批当归样品中16种氨基酸总量为4.86%~10.70%,必需氨基酸总量为0.37%~2.71%,差异氨基酸为Gly和Met;采用主成分分析对16种氨基酸含量降维,共提取了5个主成分,累积方差贡献率为80.895%,30批当归样品的综合得分为-2.44~2.42,综合得分最高的是样品13^#,最低的是样品29^#;在此基础上分别进行了聚类分析和判别分析,聚类分析将30批当归样品聚为3类,样品28^#(云南)为一类,样品29^#(陕西)为一类,其余样品(四川、甘肃与青海)聚为一类,利用判别分析建立的典则判别函数模型对30个样品进行回判验证,正确判别率为100%。

Sixteen amino acids in 30 batches of Angelica sinensis samples from different producing areas were determined by automatic amino acid analyzer, and the difference of amino acid content and quality of Angelica sinensis were evaluated combining with principal component analysis, cluster analysis and discriminant analysis. The crushed and sieved sample (1 g) was taken, and 30 mL of 0.1 mol·L^-1 hydrochloric acid solution was added. After ultrasound and cooling to room temperature, the volume of the mixture was made up to 100 mL with water. Ailquot (1 mL) was concentrated to nearly dry under vacuum at 50 ℃, and 10 mL of the sample diluent (pH 2.20) was added. The solution was dissolved by vortex, and filtrated by 0.22 μm water filtration membrane. Aspartic acid (Asp), threonine (Thr), serine (Ser), glutamic acid (Glu), glycine (Gly), alanine (Ala), valine (Val), methionine (Met), isoleucine (Ile), leucine (Leu), tyrosine (Tyr), phenylalanine (Phe), lysine (Lys), histidine (His), arginine (Arg) and proline (Pro) were determined according to the working conditions of the instrument. The results showed that the linear ranges of the standard curves of 16 amino acids were 1-200 μmol·L^-1, with detection limits (3S/N) in the range of 0.02-0.04 mg·L^-1, the spiked recoveries in the range of 90.4%-98.2%, and RSDs (n=6) of the determined values in the range of 1.3%-4.1%. The total amounts of 16 amino acids and essential amino acids were in the ranges of 4.86%-10.70% and 0.37%-2.71%, respectively, and the differential amino acids were Gly and Met. Five principal components were extracted by principal component analysis after dimensionality reduction for the contents of 16 amino acids, and the cumulative variance contribution rate was 80.895%. The comprehensive scores of 30 batches of Angelica sinensis samples were in the range of -2.44-2.42, and the highest comprehensive score was sample 13^#, while the lowest score was sample 29^#. On this basis, cluster analysis and discriminant analysis were carried out respectively. The 30 batches of Angelica sinensis samples were grouped into 3 categories by cluster analysis, and sample 28^# (Yunnan) was the first class, sample 29^# (Shaanxi) was the second class, and other samples (Sichuan, Gansu and Qinghai) were grouped together as the third class. The canonical discriminant function models established by discriminant analysis were used to back adjudication verification for 30 samples, and the correct discriminant rate was 100%.