低场核磁技术结合化学计量学法快速检测掺假阿胶产品

Rapid detection of adulterated E’jiao by low-field nuclear magnetic resonance combined with chemometrics

目的研究快速检测掺假阿胶的低场核磁共振技术(LF-NMR)新方法。方法应用低场核磁共振技术(LF-NMR)结合主成分分析法(PCA)和逐步判别分析法(Step-LDA)对掺黄明胶、新阿胶、劣质胶的阿胶进行测定。结果阿胶、黄明胶、新阿胶、劣质胶的弛豫特性不同,LF-NMR技术结合PCA可以实现对掺假阿胶与纯阿胶间的辨识,利用Step-LDA构建的判别模型对纯阿胶与不同形式掺假阿胶的区分效果更好,回判成功率均达100%,交叉验证组所有样本均正确分类,准确率达到100%,不同比例的掺假阿胶在得分图上呈规律性分布。建立掺假阿胶的Step-LDA得分模型,不同掺假物质的检测限为:黄明胶7%~9%,新阿胶7%~9%,劣质胶5%~7%。结论应用低场核磁共振技术结合化学计量学可实现掺黄明胶、新阿胶、劣质胶的阿胶的区分,LF-NMR结合Step-LDA鉴别准确率较好。

Objective To study rapid detection of adulterated E'jiao by Low-field nuclear magnetic resonance(LF-NMR).Methods LF-NMR combined with principal component analysis(PCA)and stepwise linear discriminant analysis(Step-LDA)were used to identify and quantify Colla corii asini(E'jiao)adulterated with pigskin gelatin,oxhide gelatin,and miscellaneous gelatin.Results Relaxation characteristics of E'jiao,pigskin gelatin,oxhide gelatin,and miscellaneous gelatin were different.Different kinds of adulterated E'jiao samples could be distinguished by LF-NMR and PCA.Step-LDA data was more significant,the back discrimination ratio was 100%,all the samples in the cross-validation group were correctly classified,reaching up to 100%accuracy.Different amounts of adulterants in E'jiao samples could be arranged regularly.The Step-LDA discriminant model was used to determine the detection limits of adulterant in E'jiao,The detection limits were as follows:oxhide gelatin,7%~9%,pigskin gelatin,7%~9%,miscellaneous gelatin,5%~7%.Conclusion LF-NMR and chemometrics could be used for the distinction between E'jiao,pigskin gelatin,oxhide gelatin,and miscellaneous gelatin,the classification accuracy is better by using Step-LDA.