Trace manganese detection via differential pulse cathodic stripping voltammetry using disposable electrodes: additively manufactured nanographite electrochemical sensing platforms

Additive manufacturing is a promising technology for the rapid and economical fabrication of portable electroanalytical devices. Such additively manufactured electrodes are fabricated using a range of plastic feedstock’s (filaments) with conductive nanomaterials, bought commercially or via bespoke construction. In this paper we seek to determine how our bespoke additive manufacturing feedstock’s perform as the basis of an electrochemical sensing platform towards the sensing of manganese (II) via differential pulse cathodic stripping voltammetry, despite the electrode comprising only 25 wt% nanographite and 75 wt% plastic (polylactic acid). The AM-electrodes are also critically compared to graphite screen-printed macroelectrodes (SPEs) and both are explored in model and real tap-water samples. Using optimized CSV conditions in pH 6.0, the analytical outputs using the AM-electrodes give rise to: limit of detection, 1.6 x 10-9 mol L-1 (0.09 μg L-1); analytical sensitivity, 3.4 μA V μmol-1 L; linear range, 9.1 x 10-9 mol L-1 to 2.7 x 10-6 mol L-1 (R2 = 0.998); and RSD 4.9 % (N = 10 for 1 μmol L-1). These results are compared to screen-printed electrodes (SPEs) giving comparable results providing confidence that the AM-electrodes can provide the basis of useful electrochemical sensing platforms. The proposed electroanalytical method (both AM-electrodes and SPEs) are shown to be successfully applied for the determination of manganese (II) in tap water samples and in the analysis of a certified material (drinking water). The proposed method electroanalytical based methodology is feasible to be applied for in-loco analyses due to the portability of sensing, in addition, the use of the AM-printed electrodes are attractive due to their low cost.