DETERMINING HEAVY METALS IN MUSHROOM SAMPLES BY STRIPPING VOLT-AMMETRY

Industrial cultivation of mushrooms in Ukraine in recent years has been developing at a rather high pace. A promising consumer of Ukrainian mushrooms may be the European Union market. But mushrooms are not delivered there in significant volumes due to quite high requirements for the product quality. From the biosphere, heavy metals can enter the mushrooms and make them potentially dangerous for people. The content of heavy metals: zinc, cadmium, lead, and copper in edible mushrooms (ceps, chanterelles, butter mushrooms, saffron milk-caps, and champignons) has been studied by using the stripping voltammetry method after the destruction of the matrix of mushroom samples. Sample preparation was done by the method of “wet” mineralisation with oxidising mixtures of various compositions using inorganic acids (nitrate, chloride, sulfate), and an oxidiser – hydrogen peroxide. Besides, dry ashing was used. As a result of the experiment, it has been found that the most effective method of extracting the ions of heavy metals and ensuring the accuracy of the analysis is sample preparation using nitric acid and hydrogen peroxide. The concentrations of the metals under analysis are calculated on the dry basis (mg/kg). The concentrations found for bioelements that are contained in enzymes in living organisms (zinc, copper, and toxic elements – lead and cadmium), are within the range of 51.3–72.9; 3.0–10.3; 0.2–1.32, and 0.06–0.33 mg/kg, respectively. Thus, by arranging the samples of the mushrooms under study in ascending order by the specified total content of heavy metals, we obtain the following series: ceps – butter mushrooms – chanterelles – saffron milk caps – champignons. Besides, the relative error of analysis has been calculated, and the replicability of the selected research method has been estimated. Thus, the method of stripping voltammetry can be applied in quantitative determination of heavy metals in mushroom samples.