Iron (III) porphyrin bearing 2,6-di-tert-butylphenol pendants deposited onto gold electrodes for amperometric determination of L-histidine.

A sensitive amperometric sensor for determination of L-histidine was developed using gold electrode modified with Fe(III)-porphyrin bearing three 2,6-di-tert-butylphenol groups and one palmitoyl chain. Two methods of electrode modification were applied: direct chemisorption and embedment into dodecanethiol monolayer. Both types of electrodes were used for detection of L-histidine using Osteryoung square-wave voltammetry. The sensitivity of sensors presented towards L-histidine depends on the method of electrode modification. The detection limits observed for the electrodes incorporating with Fe(III)-porphyrin host by embedment and chemisorption were in 1 and 100 nM ranges, respectively. In addition, the determination of L-histidine with electrode modified by embedment technique was more precise, in comparison to that obtained by the direct chemisorption. Applicability of gold electrodes modified with Fe(III)-porphyrin for the direct electrochemical determination of L-histidine was demonstrated using the artificial matrix mimicking human serum.