Flow-injection analysis coupled with electrochemical detection of poisonous inorganic arsenic(iii) species using a gold nanoparticle/carbon nanofiber/chitosan chemically modified carbon screen printed electrode in neutral pH solution

Abstract

Development of simple and selective detection of poisonous arsenic species [As(III)] in drinking water is the subject of continued research in the multi-disciplinary areas of chemistry and biology. In this paper is reported, a well dispersed gold nanoparticle decorated-carbon nanofiber-chitosan modified carbon screen printed electrode (SPE/CNF-CHIT@Au_nano) prepared using an inexpensive and simple electrochemical method for electro-catalytic oxidation and flow injection analysis (FIA) of inorganic As(III) species in a neutral (pH 7) phosphate buffer solution. The modified electrode has about a four times higher current signal for the arsenic oxidation than that of a gold polycrystalline electrode. The SPE/CNF-CHIT@Au_nano system is highly stable in vigorously stirred solutions. Rotating disc electrode (RDE) studies performed using a glassy carbon electrode–rotating disc electrode (GCE–RDE) with its surface modified using the CNF-CHIT@Au_nano film gave a heterogeneous rate constant, k_cat = 1.92 × 10⁴ mol⁻¹ dm³ s⁻¹ for the electrochemical oxidation of As(III). Furthermore, SPE/CNF-CHIT@Au_nano was used as an efficient electrochemical detector (ECD) for the FIA of arsenic(III) in a neutral pH solution. The present FIA-ECD shows zero interference with other common cationic and anionic species. As an analytical application, selective detection of As(III) in arsenic polluted industrial effluent and tap water samples were determined satisfactorily with good recovery values. The analysis results from FIA-ECD were comparable with those obtained using the inductively coupled plasma – optical emission spectrometry method.