Quantification of cadmium and lead in offal by SF-ICP-MS: Method development and uncertainty estimate

Offal of bovine, ovine and porcine are able to accumulate potentially toxic heavy metals, such as Cd and Pb, posing a risk for human health. For this reason, the Commission Regulation no. 466/2001 provided the maximum admitted levels for these metals in this kind of matrix (Cd, 500 ng g−1 in all kinds of offal; Pb, 500 ng g−1 in liver and 1000 ng g−1 in kidney). A method based on sector field inductively coupled plasma mass spectrometry for Cd and Pb quantification in calf liver was developed and further applied to offal of different animals. The uncertainty of measurements was calculated according to the Eurachem/Citac Guide. The method LoDs and LoQs were 3.5 and 11 ng g−1 for Cd, and 2.0 and 6.0 ng g−1 for Pb. The repeatability and the intra-laboratory reproducibility showed relative standard deviations equal to 2.25% and 1.99% for Cd and 1.49% and 6.55% for Pb. Relative expanded uncertainties at the mean value in calf liver were 4.74% for Cd and 13.8% for Pb. In Italian offal the following concentration intervals were found (in ng g−1): (i) Cd: calf, from <3.5 in spleen and lung to 96.4 in kidney; lamb, <3.5 in all offal; pig, 114 in liver and (ii) Pb: calf, from 4.03 in lung to 31.8 in liver; lamb, from 4.71 in heart to 279 in liver; pig, 9.19 in liver.