Non-targeted Detection of Multiple Frauds in Orange Juice Using Double Water-Soluble Fluorescence Quantum Dots and Chemometrics
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The feasibility of a highly sensitive “turn-off” fluorescent probe of double quantum dots (QDs) combined with chemometrics was investigated for untargeted screening of extraneous adulterants in pure orange juice (OJ), including sucrose syrup and artificial fruit powder. Pure and adulterated OJ samples were characterized by their different quenching patterns of the two separate and strong fluorescent peaks generated by the double QDs followed by chemometrics analysis. Class models of pure OJ samples (n = 117) obtained from pressing newly harvested oranges were developed using one-class partial least squares (OCPLS) based on different signal preprocessing methods, including smoothing, taking second-order derivatives (D2) and standard normal variate (SNV) transformation. As a result, D2-OCPLS model could detect at 5.0% (w/w) of sucrose syrup and 2.0% (w/w) of artificial fruit powder in pure OJ with a sensitivity (the rate of true positives) of 97.8% and specificity (rate of true negatives) of 77.0%. In conclusion, the proposed fluorescence probe with double QDs has been demonstrated to have potential for applications in rapid and sensitive screening of adulterants in OJ, which also implies promising applications to untargeted analysis of other water-soluble food samples.
KeywordsOrange juice Double quantum dots Beverage fraud One-class partial least squares (OCPLS) Untargeted detection
This work received financial support from the National Natural Science Foundation of China (Grant Nos. 21665022, 21576297, 21776321, 21706233, and 21476270), Guizhou Provincial Science and Technology Department (Nos. QKHJC1186 and QKHZC2816), the Talented Researcher Program from Guizhou Provincial Department of Education (No. QJHKYZ073), Provincial Key Disciplines of Chemical Engineering and Technology in Guizhou Province (No. ZDXK8), and the Talented Youth Cultivation Program from “the Fundamental Research Funds for the Central Universities”, South-Central University for Nationalities (No. CZP19005).
Compliance with Ethical Standards
Conflict of Interest
Lu Xu declares that he has no conflict of interest. Liuna Wei declares that she has no conflict of interest. Qiong Shi declares that she has no conflict of interest. Chen-Bo Cai declares that he has no conflict of interest. Hai-Yan Fu declares that she has no conflict of interest. Yuan-Bin She declares that he has no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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