Arsenic(III) detection in water by flow-through carbon nanotube membrane decorated by gold nanoparticles

A carbon nanotube flow-through membrane electrode decorated by gold nanoparticles (GCME) was utilized for the detection of As(III) in water. The carbon nanotube membrane was prepared by vacuum filtration of multiwalled carbon nanotubes dispersion in 1-methyl-2-pyrrolidone providing a sheet resistance of 108 +/- 6 Omega/sq with an areal mass of 60 mu g cm(-2). Gold nanoparticles were electrodeposited on the surface of GCME by applying a constant potential of -1.0 V for 15 s while a 1.0mM HAuCl4 solution in 0.1M NaCl was flowed through the GCME. The analytical response of As(III) by linear sweep anodic stripping voltammetry (LSASV) was monitored as a function of time showing that the nonconductive nature of As-0 prevents the electrodeposition of a thick layer of arsenic on the electrode surface. Thus, accumulation of a large amount of arsenic can only be achieved with a large surface area of gold nanoparticles. The calibration curve was calculated by normalization of LSASV peak charge by the volume of analyte solution flowed through the GCME since different deposition time ranging from 10 to 120 s were required to detect the different concentration used for calibration. The analytical method provided a linear range from 0.75 to 750 ppb As(III) which is suitable for environmental monitoring of this pollutant. (C) 2019 Elsevier Ltd. All rights reserved.