Validation of Microwave and ICP Parameters for Assessment of Selected Toxic Trace Elements in Fresh Fruits from Turabah Valley of Saudi Arabia

Abstract

The analytical parameters of the microwave assisted oven and of the inductively coupled plasma (ICP) method were extensively studied and well validated in terms of spectral lines (nm), linearity (R2), accuracy (recovery %), precision (RSDs), detection and quantification limits (LODs and LOQs). The validated analytical method was used to determine the contents of selected toxic trace elements (TTEs) in fresh fruit samples from Turabah Valley of Saudi Arabia. Samples were digested by a microwave-assisted oven at the ratio of 1:2.5 (v/v) (H2O2:HNO3). The R2 > 0.9990 or better, the recovery (%) were within the acceptable range (100 ± 8), the RSDs were below 4 %, the LODs and the LOQs were ranged between 0.0005-0.0556 mg kg-1 and 0.003-0.174 mg L-1, respectively. It was found that Al, Mn, Pb, As and Cd were detected in most analyzed samples, while Co, Ni and Cr were below the detection limits of the method. A considerable variation were observed with regard to TTEs concentrations in different studied fruit samples. TTEs content of fruits were compared with those of soil and well water samples in the same area. Elevated levels of Al were obtained in some fruit samples, while other elements were within the critical safety levels specified by the FAO/WHO/SASO. Some physico-chemical properties such as moisture, ash and total solid contents (%) of fruits were also estimated and compared with the reference values. The results indicate that the developed ICP method was well suited for determination of toxic and/or nutrient trace elements in fruits and possibly similar matrices.