Determination of the Trace Element Contents of Fruit Juice Samples by ICP OES and ICP-MS

Abstract

Fruit juices were analysed for their contents in a series of essential and toxic elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, V, Sb, Mo and Zn). Samples were subjected to microwave-assisted acid digestion (HNO3/H2O2), and analytes were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), in axial mode, or by inductively coupled plasma mass spectrometry (ICP-MS), with kinetic energy discrimination, using 103Rh and 89Y as internal standards. The methods were validated, showing good precision (relative standard deviations < 10%), linearity and mean analytical recovery values (89 to 103%). The ICP-OES instrumental limits of detection (LODs) were between 0.3 μg L-1 (for Mg) and 1.5 μg L-1 (for Ca), whereas ICP-MS instrumental LODs varied from 2 ng L-1 (for Co, Mo and V) to 5.7 μg L-1 (for Na). Some toxic elements (As and Sb) were not detected in the fruit juices analyzed, Cd concentrations were below the maximum permitted level established by Brazilian and European regulations and only in one sample the Pb concentration (61.7 µg L-1) exceeded current legal limits. Besides, essential elements such as Ca, Mg and Na were in high concentrations in the samples analyzed.