Evaluation of limits of detection in laser-induced breakdown spectroscopy: Demonstration for food

Laser-induced breakdown spectroscopy is an emerging technique for fast elemental analyses. It is however known to be less sensitive than the standard techniques, and its capability for trace element analysis is not yet established for most types of materials. To accurately evaluate the sensitivity of LIBS, we propose a procedure that combines a calibration-free LIBS approach with the standard methodology for the evaluation of detection limits. The procedure provides limits of detection not only for the observed elements, but for all elements for which the available spectroscopic data enable the calculation of the element-specific emission spectrum. The method is here applied to food, by determining the limits of detection for 82 elements that may alter the nutritional value of food, or present sanitary risks. Comparing the deduced limits of detection with the typical content of minerals and the upper limits of toxic elements recommended by food safety regulations, we establish a list of elements compatible with food quality monitoring via LIBS. Morevover, we demonstrate that almost all elements can be monitored if the spectra were acquired with a LIBS apparatus of optimized detection efficiency, illustrating thus the capability of LIBS for food quality monitoring.