Effects of background electrolyte and oxygen on trace analysis for lead and cadmium by anodic stripping voltammetry

Cadmium: toxicology and analysis. A review

“…Techniques which have been applied to the determination of cadmium include potentiometric stripping analysis,540~54* adsorptive stripping voltammetry, chronopotentiometry,485 galvanic stripping analysis330 and anodic stripping voltamrnetry. 398,492,542,543 Of these only the last has assumed any importance, usually in the form of differential-pulse anodic stripping voltammetry (DPASV). The capacity of DPASV for multi-element analysis is determined by the difference in reduction potential of the metals concerned.…”

“…Preconcentration times vary from several seconds to minutes depending on the concentration of analyte (being greater for low concentrations), the surface area of the electrode and the rate of mass transport which is usually enhanced by stirring the analyte solution or rotating the working electrode. Elemental mercury in the form of a static or growing drop35, 398,492,543,544 or as a thin film coated on a conducting substance such as graphite542,545,546 serves as the working electrode. Apart from using electrodes with larger surface areas such as glassy carbon and mercuryfilm electrodes, the use of a rapid 'staircase' stripping waveform has reduced analysis times.547,548 Alternatively, the signal to background ratio per unit determination time has been improved542 by using decreased pulse widths coupled with rapid potential scan rates at a mercury-film carbon-fibre electrode.…”

Electrochemical Dissolved Oxygen Removal from Microfluidic Streams for LOC Sample Pretreatment

“…3−5 With the exception of Ag, Ag amalgam electrodes, and a few special cases with the Au electrode, 6−9 classical stripping analysis of Pb requires a deoxygenation step on typical electrode materials such as graphite and mercury. 10,11 Consequently, we have become involved in the development of microfabricated electrochemical platforms for on-site removal of DO for use with our ASC devices for metal analysis. In fact, a miniaturized DO removal or regulating apparatus should also be useful for a diverse range of electroanalytical and lab-on-a-chip applications, such as voltammetric detection in capillary electrophoresis, microfluidic cell culturing platforms, and possibly O 2 -sensitive microfluidic reactors.…”

“…However, these investigations were not able to address metals such as Pb and Cd, which suffer from interference due to oxygen reduction at the potentials needed for electrodeposition . Although portable anodic stripping analyses are widespread, the associated dissolved oxygen (DO) removal step still requires direct operator intervention and thus would be unsuitable for remote automated sensing. − With the exception of Ag, Ag amalgam electrodes, and a few special cases with the Au electrode, − classical stripping analysis of Pb requires a deoxygenation step on typical electrode materials such as graphite and mercury. , Consequently, we have become involved in the development of microfabricated electrochemical platforms for on-site removal of DO for use with our ASC devices for metal analysis. In fact, a miniaturized DO removal or regulating apparatus should also be useful for a diverse range of electroanalytical and lab-on-a-chip applications, such as voltammetric detection in capillary electrophoresis, microfluidic cell culturing platforms, and possibly O 2 -sensitive microfluidic reactors. − …”