Voltammetric determination of mercury in biological samples using crown ether/multiwalled carbon nanotube-based sensor

•Preparation, characterization and electro-catalytic activity investigation of Crown/MWCNTs/CPE•Assay optimization, validation and real sample application•Mercury determination with high sensitivity, selectivity and reproducibility

An electrochemical assay for sensitive and selective determination of mercury was suggested. Preparation, characterization, and testing of the electro-catalytic activity of Crown-ether/multi-walled carbon nanotubes (MWCNTs)/CPEs were performed. The voltammetric responses of modified electrodes with various sensing elements and nanomaterials were carefully investigated. Consequently, improving the sensitivity and selectivity were achieved using a combination of 12-crown-4-ether and MWCNTs (10% w/w for each). A linear response was observed from 5 to 110 μg/ml, with the detection limit (S/N = 3) of 0.25 μg/ml. The method was interference free from many species and successfully applied for the determination of mercury in blood, urine or tab-water samples with a high accuracy and precision comparable with the reference method (Atomic Absorption Spectroscopy AAS).