摘要
选野生和栽培鱼腥草样本各25个,分别从每个样本称取0.500 0g,用5.0mL硝酸和2.0mL过氧化氢按预设程序进行微波消解,制得样品溶液25.0mL,按电感耦合等离子体质谱法(ICP-MS)测定其中22种无机元素,以45Sc、72 Ge、103 Rh、159 Tb、175 Lu和209 Bi为内标,用混合标准溶液制得标准曲线,各元素的线性关系良好。在已知样本的基础上,按标准加入法进行回收率和精密度试验,测得回收率为82.0%~114%,测定值的相对标准偏差(n=6)为0.20%~4.5%。对所测得数据进行独立样本t检验统计分析,结果表明:地理生长环境、种植技术和人类活动等因素造成了野生和栽培鱼腥草中无机元素含量的差异。对50个鱼腥草样本×22个元素变量数据矩阵(50×22)进行主成分分析,其结果基本反映了无机元素与野生和栽培鱼腥草之间的关系,但不能进行准确的鉴别。进一步对50×22个元素变量数据通过逐步判别分析,筛选出具有显著作用的变量元素(Na、K、Cr、Se、Cd),建立了典型判别函数和线性判别函数模型,达到了两种不同类型鱼腥草的完全区分。为验证判别模型的可靠性,进行了回代检验和交叉验证,得到正确判别率为100%。据此认为应用ICP-MS结合化学计量学方法可实现野生和栽培鱼腥草的鉴别。
Twenty-five samples each of wild and domesticated Houttuynia cordata were collected.A portion of 0.500 0 g was taken from each of the samples and digested with 5.0 mL of HNO3 and 2.0 mL of H2O2 in a microwave digestor under prescribed programme to prepare a sample solution of 25.0 mL.Twenty-two inorganic elements were determined in each of the sample solutions by ICP-MS.45Sc,72Ge,103Rh,159Tb,175Lu and 209 Bi were chosen as internal standards.Standard curves were prepared by mixed standard solutions.Good linear relationships of standard curves of the 22 elements were obtained.Tests for recovery and precision were performed by addition of standards to a known sample,giving values of recovery in the range of 82.0% to 114% and RSDs(n=6)in the range of 0.20%-4.5%.It was shown by the results of statistical study of t-test,distinctive differences of contents of inorganic elements in the 2 kinds of Houttuynia cordata were due to the differences of geographical and growing environments,the cultivation techniques,and mankind activities.In further,the principal component analysis was applied to the study of matrixes(50×22)of variable data given by the 50 samples of the Houttuynia cordata and the 22 inorganic elements.As shown by the results obtained,relationships between the contents of the inorganic elements and the kinds(i.e.wild or domesticated)of the Houttuynia cordata were revealed,but a clear differentiation between the wild and domesticated Houttuynia cordata was still not attained.Then,the progressive discriminant analysis was applied to study the 50×22 elemental variable data,five variable elements(Na,K,Cr,Se,Cd)having significant effect were sieved,and models of typical discriminant function and linear discriminant function were established,attaining to complete and ultimate differentiation between the 2 kinds of Houttuynia cordata.To verify the reliability of the discriminant models,tests of back-substitution and cross-validation were applied,and rate of discriminant accuracy of 100% was obtained.It was conside
作者
周美丽
范晓旭
杨春花
杨伟
ZHOU Meili;FAN Xiaoxu;YANG Chunhua;YANG Wei(Food Inspection and Testing Institute of Dali,Dali 671000,China)
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2019年第11期1305-1311,共7页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
