Determination of heavy metal chromium in pork by laser-induced breakdown spectroscopy

Meat can be polluted by heavy metals during the feeding of livestock and processing of meat. It is necessary to monitor the concentration of toxic metals in meat. The element chromium (Cr) in pork was selected as a determination target for this work. Fresh pork was polluted in a Cr solution to create a different content level, then dried and pressed into pellets to eliminate the effect of water and improve the stability and sensitivity of laser-induced breakdown spectroscopy (LIBS). The spectra of pressed pellets were collected at optimized LIBS experimental parameters. After that, the real content of samples was obtained by atomic absorption spectroscopy. Characteristic lines Cr I 425.43, Cr I 427.48, and Cr I 428.97 were verified, and a model comparing the LIBS intensity of the line peak and the actual concentration of Cr was constructed. The results showed that the model has better predicted precision and accuracy, especially applying the line Cr I 425.43 for calibration. This work makes it obvious that LIBS has food safety potential for detecting residue of heavy metals in meat. (C) 2016 Optical Society of America