Detection o micro-toxic elements in commercial coffee brands using optimized dual-pulsed laser-induced spectral analysis spectrometry

摘要

A fast detection system based on dual-pulsed laser-induced breakdown spectroscopy (DP-LIBS) was successfully developed and optimized for the estimation of micro-toxic element contents in commercial coffee brands to monitor pollution and ensure food safety. A series of 13 various coffee brands were quantitatively analyzed in this study utilizing DP-LIBS and a standard analytical technique like inductively coupled plasma/optical emission spectrometry (ICP-OFS). The micro-toxic elements, such as aluminum (Al), lead (Pb), zinc (Zn), and chromium (Cr), that exist in the coffee brands were exactly identified. We prepared standard matrices in a known concentration in the coffee sample to draw the standard calibration curves for each element, as well as by utilizing a tactic based on the intense line emission of the element of interest as a quantitative analysis. The analytical routines were approved under the expectations that the plasma created by the dual-pulsed lasers was in local thermodynamic equilibrium (LTE) and was optically thin. We investigated the influence of different parametric dependence studies to enhance our DP-LIBS detection sensitivity. Furthermore, the precision of our DP-LIBS data for determining the concentration of micro-toxic elements present in coffee samples was validated via the ICP-OES technique. The results achieved by the DP-LIBS technique were in full agreement with the ICP-OES results. In addition, the estimated limit of detection of our DP-LIB spectrometer for Al, Pb, Zn, and Cr were 105.13 +/- 07, 90.17 +/- 12, 83.58 +/- 15, and 68.78 +/- 09 mu g L-1, respectively. The suggested protocols demonstrated the excellent benefits of the DP-LIBS for the detection of micro-toxic elements existing in coffee and for checking the purity and quality of food products. (C) 2018 Optical Society of America