A new ecological and low-cost alternative based on the electrolytic dissolution of stainless steel for the immediate voltammetric determination of manganese using 3D printed electrodes

Abstract

The chemical analysis of stainless steels are generally performed using spectrometric techniques after sample preparation by acid digestion. This is an expensive approach and is not considered environmentally friendly due to the excessive use of reagents. In this context, a new sustainable strategy was developed here for monitoring manganese levels in seven stainless steels samples. The analysis was conducted after sample preparation by electrolytic dissolution (ED) performed directly in the voltammetric cell using differential pulse cathodic stripping voltammetry (ED-DPCSV). For this purpose, a fully 3D-printed sensor manufactured with a laboratory-made conductive filament composed of polylactic acid (PLA) and graphite (PLA/GRA, 60:40 % wt) was properly characterized and applied for the voltammetric measurements. The ED conditions were optimized, requiring only 110 s. The relative standard deviation for signals obtained for ED process was below 3.3 %, and a nanomolar-scale detection limit of 28.0 nmol/L (1.54 µg/L) was achieved using the voltammetric method. The sensor proved to be interference-free for a wide variety of metal ions. Finally, the manganese levels found in the stainless steel samples were statistically comparable to results obtained by optical emission spectrometry (ICP OES).