Identification of rhinoceros keratin using direct analysis in real time time-of-flight mass spectrometry and multivariate statistical analysis
Identification of rhinoceros keratin using direct analysis in real time time-of-flight mass spectrometry and multivariate statistical analysis
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DOI：
10.1002/rcm.8285
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发表时间：
2018-12-30
影响因子：
2
通讯作者：
Espinoza, Edgard O.
中科院分区：
文献类型：
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作者：
Price, Erin R.;McClure, Pamela J.;Espinoza, Edgard O.
犀牛角贸易在国际上受到管制或禁止，因为认识到它对全世界野生种群的影响。法律和法规的执行取决于成功识别何时发生违规行为，这因替代/仿制犀牛角蛋白的存在而变得复杂（例如，牛角角蛋白）。在这项研究中，我们评估的潜力，直接分析真实的时间（DART）电离配对飞行时间质谱（DART-TOFMS）分类不同的角蛋白类型从四个分类组：犀牛，牛科动物，国内马，穿山甲。方法收集5种犀牛角蛋白、8属牛科动物角蛋白、马蹄角蛋白和穿山甲鳞片角蛋白共156个样品的光谱。Fisher比率分析确定了表征每个类别的最重要的离子，并且这些离子用于训练模型，该模型由143个光谱组成。核判别分析（KDA）被用来分类不同的群体。结果所采集的各分类群的光谱特征明显。化学型表明，光谱的犀牛，牛科动物，和国内的马是彼此相似的，而穿山甲的化学型显示出不同的化学配置文件。KDA建立的模型解决了每个分类组：95%的样本使用留一交叉验证正确分配。未用于模型开发的13个盲样均正确归类为分类学来源。结论DART-TOFMS是一种可靠的角蛋白分类鉴定方法。这种分析可以用少量的角蛋白进行，样品制备最少，成本低，速度快，使其成为鉴定犀牛角和其他角蛋白类型的潜在有价值的工具。
Rationale Trade in rhinoceros horn is regulated or banned internationally in recognition of its impact on wild populations worldwide. Enforcement of the laws and regulations depends on successfully identifying when violations occur, which is complicated by the presence of alternative/imitation rhinoceros horn keratin (e.g., bovid horn keratin). In this study, we assess the potential for Direct Analysis in Real Time (DART) ionization paired with Time-Of-Flight Mass Spectrometry (DART-TOFMS) to classify different keratin types from four taxonomic groups: rhinoceros, bovid, domestic horse, and pangolin. Methods The spectra of 156 keratin samples from all five rhinoceros species (horn keratin), eight genera of bovids (horn keratin), domestic horses (hoof keratin), and all extant species of pangolins (scale keratin) were collected. Fisher ratio analysis identified the most important ions that characterized each class and these ions were used for the training model, which consisted of 143 spectra. Kernel Discriminant Analysis (KDA) was used to classify the different groups. Results The spectra collected for each taxonomic group are distinctive. The chemotypes demonstrate that the spectra of rhinoceros, bovids, and domestic horse are similar to each other, whereas the chemotypes of pangolins show a different chemical profile. The model built by KDA resolved each taxonomic group: 95% of samples were correctly assigned using leave-one-out cross validation. The 13 blind samples not used in model development were all correctly classified to taxonomic source. Conclusions DART-TOFMS appears to be a reliable approach for taxonomic identification of keratin. This analysis can be carried out with a small sliver of keratin, with minimal sample preparation, inexpensively and quickly, making it a potential valuable tool for identification of rhinoceros horn and other keratin types.