Abstract: In this study, laser induced breakdown spectroscopy (LIBS) combined with univariate calibration, internal calibration and partial least square (PLS) was used for simultaneous quantitative analysis of P, Fe, Al, Mn, K, Mg, Ca and Na in cod samples. A series of cod standard samples with different concentrations of these elements were prepared, and reference values for each element concentration were determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES). The cod samples were compressed into tablets and their LIBS spectra were collected. The characteristic spectral lines were selected for each element, and the three quantitative methods of univariate calibration, internal calibration and PLS were compared. The results showed that PLS was superior to traditional univariate calibration and internal calibration, and had higher prediction accuracy and precision. The relative error (RE) of the predicted concentration ranged from 0.96% to 13.27%, and the relative standard deviation (RSD) ranged from 2.02% to 7.55%. This work showed that LIBS had great potential in the rapid and non-directional detection of various elements in cod and even other aquatic products, and could lay a foundation for the development of a portable LIBS device for multi-element analysis of aquatic products in the future.

Key words: laser induced breakdown spectroscopy; cod; partial least squares; multi-element; simultaneous detection