Pypin, A.A.; Shik, A.V.; Stepanova, I.A.; Doroshenko, I.A.; Podrugina, T.A.; Beklemishev, M.K. A Reaction-Based Optical Fingerprinting Strategy for the Recognition of Fat-Soluble Samples: Discrimination of Motor Oils. Sensors2023, 23, 7682.
Pypin, A.A.; Shik, A.V.; Stepanova, I.A.; Doroshenko, I.A.; Podrugina, T.A.; Beklemishev, M.K. A Reaction-Based Optical Fingerprinting Strategy for the Recognition of Fat-Soluble Samples: Discrimination of Motor Oils. Sensors 2023, 23, 7682.
Pypin, A.A.; Shik, A.V.; Stepanova, I.A.; Doroshenko, I.A.; Podrugina, T.A.; Beklemishev, M.K. A Reaction-Based Optical Fingerprinting Strategy for the Recognition of Fat-Soluble Samples: Discrimination of Motor Oils. Sensors2023, 23, 7682.
Pypin, A.A.; Shik, A.V.; Stepanova, I.A.; Doroshenko, I.A.; Podrugina, T.A.; Beklemishev, M.K. A Reaction-Based Optical Fingerprinting Strategy for the Recognition of Fat-Soluble Samples: Discrimination of Motor Oils. Sensors 2023, 23, 7682.
Abstract
Optical “fingerprints” are widely used in chemometrics-assited recognition of samples of different nature. An emerging trend in this area is the transition from obtaining "static" spectral data to reactions occurring over time. The indicator reactions are usually carried out in aqueous solutions; in this study we have developed the reactions that occur in an organic solvent, which makes it possible to recognize fat-soluble samples. In this capacity, we used 5W40, 10W40 and 5W30 motor oils of 4 manufacturers, totally 6 samples. The procedure involved mixing of the dye, sample, and reagents (HNO3, HCl, or t-butyl hydroperoxide) in ethanolic solution in a 96-well plate and measuring absorbance or near-IR fluorescence intensity every several minutes during 20–55 min. The obtained photographic images were processed by linear discriminant analysis (LDA) and k-nearest neighbors algorithm (kNN). The discrimination accuracy was evaluated by using the validation procedure. Reaction of oxidation of a dye with nitric acid allowed to recognize all 6 samples with 100% accuracy by LDA. Merging data of 4 reactions that did not provide complete discrimination ensured an accuracy of 93% by kNN technique. The developed indicator systems have good prospects for the discrimination of other fat-soluble samples. Overall, the results confirm the viability of the kinetic-based discrimination strategy.
Keywords
optical sensing; absorbance; fluorescence; fingerprinting; recognition of motor oils; oxidation of carbocyanine dyes; linear discriminant analysis; k-nearest neighbors algorithm
Subject
Chemistry and Materials Science, Analytical Chemistry
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
