Fast, clean, low-cost screening of cadmium and lead in the mussel Mytilus galloprovincialis Lmk. by visible spectroscopy and partial least squares regression

The potential of visible (VIS) spectroscopy for screening cadmium and lead contents in the mussel Mytilus galloprovincialis Lmk. was assessed. The spectra of the samples were recorded (400-700 nm). The Cd and Pb contents were determined by graphite furnace atomic absorption spectroscopy, and were regressed against different spectral transformations by modified partial least square (PLSm) regression. Coefficients of determination in the cross-validation (Cd = 0.95; Pb = 0.77) were indicative of equations with excellent and good quantitative information, respectively. The standard deviation to standard error of cross-validation ratio (Cd = 4.43; Pb = 2.10) showed sufficient predictive accuracy for the equations to be used for screening purposes. PLSm loading plots corresponding to the first terms of the equations showed that chromophores influenced them significantly. This pioneering use of the VIS spectrum to predict Cd and Pb in mussels represents an important saving in time and cost of analysis in comparison to other methods.