Detection of the adulteration of fresh coconut water via NMR spectroscopy and chemometrics.
Detection of the adulteration of fresh coconut water via NMR spectroscopy and chemometrics.
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DOI：
10.1039/c8an01964a
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
Paul I. C. Richardson;H. Muhamadali;Y. Lei;A. Golovanov;David I. Ellis;R. Goodacre
中科院分区：
文献类型：
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作者：
Paul I. C. Richardson;H. Muhamadali;Y. Lei;A. Golovanov;David I. Ellis;R. Goodacre
在这里，我们应用核磁共振波谱结合化学计量学来量化掺假新鲜椰子水，水糖混合物拉伸。椰子水是从年轻的哥斯达黎加椰子中提取出来的，并掺入了各种浓度的糖溶液。用1D质子核磁共振光谱和化学计量学对45个样品进行了分析。结果显示，定量检测高度敏感，糖掺杂的检出限为1.3%，预测均方根误差为0.58%。有趣的是，我们发现了化学位移的规律漂移，苹果酸信号的线形变化伴随着掺假水平的增加。进一步调查发现，这是由样品中二价阳离子（如镁）浓度的变化引起的。可以得出结论，1H NMR光谱可以准确定量该产品的掺假程度，并发现苹果酸信号的移位和线形可以用作新鲜椰子水部分替代外部成分（如糖混合物）的潜在诊断标记。
Here, we applied NMR spectroscopy in combination with chemometrics to quantify the adulteration of fresh coconut water, stretched with water-sugar mixtures. Coconut water was extracted from young Costa Rican coconuts and adulterated with concentrations of various sugar solutions. A total of 45 samples were analysed by 1D proton NMR spectroscopy and chemometrics. Results showed highly sensitive quantification, with a limit of detection of adulteration with sugars of 1.3% and a root-mean-squared error of prediction of 0.58%. Interestingly, we identified a regular drift in the chemical shift and a change in the lineshape of malic acid signals concomitant with increasing levels of adulteration. On further investigation, this was found to originate from changes in the concentration of divalent cations, such as magnesium, within the samples. It can be concluded that 1H NMR spectroscopy enables accurate quantification for the degree of adulteration in this product, with the added discovery finding that the shift and lineshape of the malic acid signal can be utilised as a potential diagnostic marker for partial substitution of fresh coconut water with extrinsic components such as sugar mixtures.