Study on Catalytic Adsorptive Stripping Voltammetry of Trace Cobalt at Bismuth Film Electrodes

Abstract

Bismuth film electrodes (BiFE) prepared by plating a glassy carbon support ex situ from a solution containing 0.5 M LiBr and 1 M HCl was tested for the determination of cobalt traces using adsorptive stripping voltammetry (AdSV) and catalytic adsorptive stripping voltammetry (CAdSV). AdSV enables one to determine cobalt as the Co(II)-dimethylglyoximate (Co-DMG) complex down to 0.3 mg/L Co. Addition of NaNO 2 to the solution containing dimethylglyoxime in ammonia buffer provides a 15-fold enhancement of the voltammetric signal of cobalt due to the catalytic effect occurring during the reduction of Co(II)-DMG. Utilization of the bismuth film electrode under optimized conditions assures a stable catalytic adsorptive stripping voltammetric response for Co, with an extremely high sensitivity (1.75 mA/(mg/L)), good precision (RSD 3%), and a low detection limit (0.07 mg/L Co with 60 s of adsorptive accumulation). The results of the measurement of the catalytic cobalt response in the presence of DMG and nitrite under hydrodynamic amperometric conditions have shown the BiFE to be an attractive and suitable tool for the rapid determination of cobalt at low mg/L level in both batch and flow systems.

A Decade with Bismuth‐Based Electrodes in Electroanalysis

“…Among a sextet of new papers [25 -30], one could also find the pioneering report from Greece [26], representing -from a retrospective point of view -the very beginnings of a highly productive electroanalytical group from Thessaloniki. Otherwise, the season of extremely hot summer in Europe indicated that the era of basic characterizations and simple model analyses was almost over and the future would be in a sign of more specialized applications, such as highly sensitive detections via electrocatalytic effect [25], simultaneous determinations of trace metals in environmental samples [26,27], or monitoring of heavy metals in food products described by a debuting group from Italy [28].…”

Rapid and sensitive determination of cobalt by adsorptive cathodic stripping voltammetry using tin–bismuth alloy electrode

“…The detection limit was given by the equation C L = 3S bl /S, where S bl is the standard deviation of the blank measurements and S is the sensitivity of the calibration graph. The detection limit of Co 2+ for 60 s accumulation was calculated to be 44 pM, which is lower than that at hanging mercury drop electrode [2,16], stationary mercury drop electrode [37], cylindrical silver-based renewable amalgam film electrode [13,38], in situ and ex situ plated bismuth film electrode [39][40][41][42], solid bismuth disk vibrating electrode [43], in situ plated lead film glassy carbon electrode and screen-printed electrode [9,27,28], and in situ plated leadcopper film electrode [30]. The data for the application of various electrodes in the AdCSV determination of Co 2+ is show in Table 2.…”

Fabrication of Bismuth/Multi‐walled Carbon Nanotube Composite Modified Glassy Carbon Electrode for Determination of Cobalt

“…23 Most of the bismuth film electrodes developed for cobalt determination show a higher detection limit than mercury electrodes even when the catalytic processes are employed. 3,4,10,11 This paper reports for the first time the adsorptive cathodic stripping behavior of a Bi/MWNT composite modified electrode, which shows a dramatically enhanced sensitivity to cobalt with a detection limit below 1×10 -10 mol/L. Comparisons will be shown among the bare glassy carbon electrode, BiFE, MWNT and Bi/MWNT modified electrodes.…”

“…7 These electrodes have been applied to determination of many heavy metals such as cadmium, 8 lead, 8 tin, 9 nickel 3,4 and cobalt. 3,4,10,11 Carbon nanotubes (CNT) have attracted much attention in electroanalysis due to the unique mechanical, electronic, geometrical and chemical properties. [12][13][14] In recently years, it has been found that combining metal particles, such as platinum, 15 nickel, 16 copper 17 and palladium, 18 with CNT-modified electrodes can provide a promising way for fabrication of novel electrodes with largely improved performances.…”