Signal amplification of dopamine using lanthanum hexacyanoferrate-modified electrode

Abstract

A sensitive and selective electrochemical sensor has been developed using an electroactive polynuclear lanthanum hexacyanoferrate (LaHCF) complex with counter alkali cation (Na+) deposited on the glassy carbon (GC) electrode (GC/LaHCF). The GC/LaHCF-modified electrode is found to be an excellent transducer in mediating the oxidation of neurotransmitter molecule such as dopamine (DA) at physiological pH 7.2. Interestingly, the GC/LaHCF-modified electrode amplifies a 50-fold enhancement in the oxidation of DA signal compared to the bare GC electrode. Besides, the GC/LaHCF-modified electrode shows excellent selectivity in the voltammetric oxidation of DA in the presence of ascorbic acid (AA). Under optimal conditions, the GC/LaHCF modified electrode shows a linear relationship in DA oxidation between 0.1 × 10−6 and 1.0 × 10−6 M with the detection limit of 1 × 10−8 M (10 nM). Importantly, practical utility of the modified electrode is good in studying the real sample analysis such as dopamine hydrochloride injection assay. The effect of an electroactive polynuclear lanthanum hexacyanoferrate deposited on glassy carbon electrode has been studied for dopamine oxidation under physiological condition. The main advantages are signal amplification, excellent selectivity and application to real sample analysis. The modified electrode can be used to study dopamine in the submicromolar concentration.