Electrochemical sensor modified with gold and arenediazonium salts for the determination of copper and mercury in human’s hair

Current article presents the results of using a solid carbon-containing electrochemical sensor modified with arenediazonium salts (ME-ADT-COOH) for the joint determination of copper and mercury in human hair. The sensitivity of the determination of copper and mercury ions using a graphite electrode modified with gold and arenediazonium salts with a substituent carboxy group is higher compared to the other carbon-containing modified electrodes. The influence of the concentration of arenediazonium tosylates with various substituents on the obtained analytical signal was studied. The conditions for the manufacturing the new carbon-containing modified electrochemical sensor have been developed. The effective surface area of the modified electrode was calculated, which was estimated using a cyclic voltammogram against the background of 0.1 M KCl with the addition of potassium hexacyanoferrate (С=5*10-4mol/l) salts and calculated using the Randles-Ševčík equation for the reversible electrode process. A linear range of determined concentrations in the voltametric determination of microelements on the arendiazonium-modified gold-graphite electrode was established - from 0.1 to 12 µg/g. The error of the determination did not exceed 25 %. The correctness of the results of the determination of copper and mercury in real objects by the “introduced-found” method, which correlates well with the known values, has been verified.