Direct Determination of Heavy Metals in Honey by Potentiometric Stripping Analysis

Abstract

Honey is a valuable nutritious food rich in simple sugars, aminoacids, proteins and minerals. In addition, this food product contains natural phenols and flavonoids, responsible for some bioactive properties. Due to known health benefits of honey and its exquisite flavour this foodstuff is readily consumed by children and wide population imposing necessity of strict quality control. One of quality criteria is the content of heavy metals. Elevated content of heavy metals in honey may result from environmental or processing contamination, or may originate from soil or plant species that honey is derived from.

In this work twenty five samples of honey from Serbia, Montenegro and Bosnia and Herzegovina were analysed in respect to zinc, cadmium, lead and copper content. Honey samples were analysed directly, without sample preparation, by applying potentiometric stripping analysis. Zinc, cadmium and lead were quantitated by using indium as an internal standard, whereas copper was determined by standard addition method. Method accuracy was confirmed by blind analysis of standard samples and with good recovery results which, for analysed samples, were in the range 91-101%. In all analysed sampled determined metals contents were in the range permitted by Serbian regulations. Cadmium was not detected in any of the analysed samples, whereas the content of other metals were in the range of 0.01-3.6 mg/g for zinc, 0.02-0.8 mg/g for lead and 0.1-2.4 mg/g for copper, respectively.