Solid phase extraction based on the use of agaricus arvensis as a fungal biomass for the preconcentrations of Pb and Al prior to their determination in vegetables by ICP-OES.

Abstract

A solid phase extraction (SPE) method based on the use of a fungal biomass as sorbent was developed for the preconcentrations of Pb and Al. Agaricus arvensis was immobilized on Amberlite XAD-4 and loaded onto a column. Important parameters such as pH and flow rate of the solution, amount of biosorbent and resin, volume of sample solution, which affect the efficiency of the preconcentration procedure for Pb and Al, were optimized. The effect of possible interfering ions, i.e., Cd2+, Cu2+, Ni2+, Zn2+, Co2+, Na+, K+, Ca2+, Mg2+, and Fe2+, was investigated. Experiments on the repeatability of the solid phase column showed that the same column could be used at least 30 cycles without loss of the biosorption efficiency for the recovery of Pb and Al. The limit of detection (LOD) of Pb and Al was found to be 0.10 ng mL-1 and 0.03 ng mL-1, respectively. The sensitivity of ICP-OES improved 39.8-fold for Pb and 39.5-fold for Al. Linearity was obtained in the concentration range of 1.25–50.0 ng mL-1 for Pb and 0.5–50.0 ng mL-1 for Al. The relative standard deviation (RSD) of the method under optimum conditions was lower than 8.4% (n=5) for Pb and Al, which was validated through the analysis of certified reference tea and poplar leaves samples. The biosorption capacity of immobilized Agaricus arvensis for Pb and Al was found to be 31.2 mg g-1 and 45.7 mg g-1, respectively. The developed method was applied to determine the concentrations of Pb and Al in various edible vegetable samples (cucumber, okra, tomato, beans, aubergine, watermelon, zucchini, pepper, melon, lettuce, roka, purslane, scallion, cress, parsley, cabbage, sugar cane, and basil) grown along the cultivated banks of the Tigris River in Diyarbakır, Turkey.