Quantitative models for detecting the presence of lead in turmeric using Raman spectroscopy

Abstract

© 2020 Elsevier B.V. The current study presents a novel methodology to quantify lead in Turmeric using Raman spectroscopy. In this study, Partial Least Squares Regression (PLSR) was used for the quantification of lead. For calibration purposes, different amounts of lead were added to Turmeric samples encompassing a concentration range between 4 and 25 ​μg ​g−1. Since lead does not show any Raman band, for the purposes of this study, a complex was formed, its solvent was evaporated and the complex solid samples were registered with a Raman instrument. Raman measurements were performed in two different modes, -diffuse reflectance and transmission-. The PLSR models developed from Raman spectra of two data acquisition modes were evaluated in order to determine the suitability of both acquisition modes for quantifying lead content. The results indicated that diffuse reflectance showed better performance in terms of accuracy and robustness with a bias of 0.55 ​μg ​g−1, a relative standard error of prediction (RSEP) of 8.5% and a correlation between the predicted and reference values (R2) of 0.967. Despite the low lead concentration in the samples, the proposed model allows the quantification of the lead content in a fast and simple way.