Gaussian process regression coupled with mRMR to predict adulterant concentration in cocaine

Street cocaine is often mixed with various substances that intensify its harmful effects. This paper proposes a framework to identify attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) intervals that best predict the concentration of adulterants in cocaine samples. Wavele...

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Bibliographic Details
Published in:Journal of pharmaceutical and biomedical analysis 2024-09, Vol.248, p.116294, Article 116294
Main Authors: Anzanello, M.J., Fogliatto, F.S., John, D., Ferrão, M.F., Ortiz, R.S., Mariotti, K.C.
Format: Article
Language:English
Subjects:
ATR-FTIR
Cocaine adulterants
Gaussian Process regression
MRMR
ReliefF
Wavelength selection
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Summary:Street cocaine is often mixed with various substances that intensify its harmful effects. This paper proposes a framework to identify attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) intervals that best predict the concentration of adulterants in cocaine samples. Wavelengths are ranked according to their relevance through ReliefF and mRMR feature selection approaches, and an iterative process removes less relevant wavelengths based on the ranking suggested by each approach. Gaussian Process (GP) regression models are constructed after each wavelength removal and the prediction performance is evaluated using RMSE. The subset balancing a low RMSE value and a small percentage of retained wavelengths is chosen. The proposed framework was validated using a dataset consisting of 345 samples of cocaine with different amounts of levamisole, caffeine, phenacetin, and lidocaine. Averaged over the four adulterants, the GP regression coupled with the mRMR retained 1.07 % of the 662 original wavelengths, outperforming PLS and SVR regarding prediction performance. •A new framework for predicting cocaine adulterant concentration•Two feature selection approaches integrated to Gaussian Process are tested•Predictions were substantially improved when using reduced regions of the spectra•The proposed framework was validated in four adulterants
ISSN:0731-7085
1873-264X
1873-264X
DOI:10.1016/j.jpba.2024.116294