Low-cost reusable sensor for cobalt and nickel detection in aerosols using adsorptive cathodic square-wave stripping voltammetry

Abstract

A low-cost electrochemical sensor with Nafion/Bi modification using adsorptive stripping voltammetry for Co and Ni determination in airborne particulate matter and welding fume samples is described. Carbon stencil-printed electrodes (CSPEs) manufactured on low-cost PET films were utilized. Dimethylglyoxime (DMG) was used as a Co(II) and Ni(II) chelator with selective chemical precipitation for trace electrochemical analysis. Electrochemical studies of the Nafion/Bi-modified CSPE indicated a diffusion-controlled redox reaction for Co and Ni measurements. The Nafion coating decreased the background current and enhanced the measured peak current. Repeatability tests based on changes in percent relative standard deviation (RSD) of peak current showed the electrode could be used at least 15 times before the RSD exceeded 15% (the reported value of acceptable repeatability from Association of Official Analytical Chemists (AOAC)) due to deterioration of electrode surface. Limits of detection were 1 μg L−1 and 5 μg L−1 for Co and Ni, respectively, which were comparable to electrochemical sensors requiring more complicated modification procedures. The sensor produced a working range of 1–250 and 5–175 μg L−1 for Co and Ni, respectively. Interference studies showed no other metal species interfered with Co and Ni measurements using the optimized conditions. Finally, the developed sensors were applied for Co and Ni determination in aerosol samples generated from Co rods and a certified welding-fume reference material, respectively. Validation with ICP-MS showed no statistically different results with 95% confidence between sensor and the ICP methods.

Specific Dopamine Sensing Based on Short-Term Plasticity Behavior of a Whole Organic Artificial Synapse

“…The deviation values are lower than the recommended value from the Association of Official Analytical Chemists (AOAC) (15%). 29,30 We now discuss a possible origin for the selectivity of DA vs AA or UA by our PEDOT:PSS based artificial synapse, that works even without a specific recognition moiety for DA. The sensing mechanism may rely on a preferential, stronger interaction of DA with PEDOT:PSS at the PEDOT:PSS/ electrolyte interface.…”

“Dip-and-read” paper-based analytical devices using distance-based detection with color screening

“…A stainless steel welding fume sample certified for Cr, Fe, Mn and Ni (SSWF-1) was obtained from the Health & Safety Laboratory (Harpur Hill, Buxton, UK). Aqua regia digestion of the SSWF-1 material was performed by the method previously reported by our group 55 with a slight modification. Briefly, 4.9 mg of the SSWF-1 material was digested into 1 mL of aqua regia heated at 70 °C for 15 min.…”

An electrochemical paper-based analytical sensor for one-step latex protein detection

“…The circle-shaped working electrode had a 3 mm diameter. The electrodes were dried at 65 °C for 1 h. 31,32 A ring-shaped piece of adhesive tape was used for confining the solution droplet to the electrodes (Fig. S1a †).…”