Miniature 3D-printed integrated electrochemical cell for trace voltammetric Hg(II) determination

This work describes an integrated miniature all-3D-printed device for the determination of trace Hg(II) by anodic stripping voltammetry (ASV). The device is fabricated through a single-step printing process using a dual-extruder 3D printer and is composed of a mini vessel (printed from a polylactic acid (PLA) filament) and of 3 thermoplastic electrodes printed from a carbon-loaded PLA conducive filament and integrated at the bottom of the vessel. The working electrode surface is modified with a thin gold film electroplated in situ. The formation of the gold deposit was studied by linear sweep voltammetry and optical microscopy and the electrode materials as well as the chemical and instrumental conditions for Hg(II) determination were optimized. The limit of detection for Hg(II) is 0.52 mu g L-1, the within-sensor repeatability (expressed as the coefficient of variation of 8 measurements of 20 mu g L-1 Hg(II) at the same device) is 3.9 % and the between-cell reproducibility (expressed as the coefficient of variation 5 measurements of 20 mu g L-1 Hg(II) conducted at different cells) is 8.9 %. The 3D-printed device was successfully applied to the determination of Hg(II) in bottled water and fish oil samples.