Stripping voltammetry simultaneous detection

For chemical monitoring, a list of priority substances has been established that includes metals such as cadmium, lead, and nickel. As far as metals are concerned, voltammetric techniques and more precisely electrochemical stripping analysis has long been recognized as a powerful technique in environmental samples. In particular, anodic stripping voltammetry (ASV) coupled with screen-printed electrodes (SPEs) is a great simplification in the design and operation of on site heavy metal determination in water, for reasons of cost, simplicity, speed, sensitivity, portability and simultaneous multi-analyte capabilities. The wide applications in the field for heavy metal detection were extensively reviewed (Honeychurch and Hart, 2003 Palchetti et al., 2005). 

Adsorptive stripping voltammetry (ASV) is another specialised technique where the SMDE electrode is used for reducible species and carbon paste electrodes for oxidisable ones. This allows enrichment (by factors of 100-1000) of ions at the working electrode before stripping them off for measurement this improves the detection limits. This technique is rapid, sensitive (10 "M), economical and simple for trace analysis. The basic instrumentation for stripping analysis is apotentiostat (with voltammetric analyser), electrode and recorder. While voltammetry is generally very useful for compounds that do not have a chromophore or fluorophore, stripping analysis is the best analytical tool for direct, simultaneous determination of metals of environmental concern, e.g. lead, cadmium, zinc and copper in sea water. 

An integrated electronic tongue consisting of a multiple light-addressable potentiometric sensor (MLAPS) and two sets of electrochemical electrodes was developed to simultaneously detect Fe (111) and Cr (VI) ions and other heavy metals, respectively [64], The MLAPS was based on chalcogenide thin film while the electrochemical electrodes used stripping voltammetry. It has been suggested by the authors that these methods are suitable for the detection of heavy metals in wastewater or seawater. 

Anodic stripping voltammetry, potentiometric stripping voltametry, and differential pulse polarography are used for the simultaneous determination of up to 10 analytes at extremely low concentrations (detection limits <0.01 pgl ). Electroanalytical techniques are applicable for 30 elements. Stripping analysis allows differentiation between chemical forms but is subject to interference from adsorption... 

In order to obtain the required sensitivity levels, preconcentration techniques are needed. Adsorptive stripping voltammetry (ASV) is, in this respect, a method of choice. Specific accumulation potentials applied for 30-60 s before the measurement have shifted the detection levels to the 10 -10 mol 1 interval (e.g. buprofezin requires an accumulation potential of —0.8V over a period of 60s on the hanging mercury electrode before quantitation by means cyclic voltammetry or differential pulse voltammetry, desmetryn needs an accumulation potential of —0.7 V over a period of 50 s before differential pulse voltammetry determination from micellar or emulsified media). Attempts for simultaneous determination of complex mixtures of... 

Yang, X., Quin, H., Gao, M. and Zhang, H. (2011) Simultaneous detection of Ponceat 4R and tartrazinein food using adsorptive stripping voltammetry on an acetylene black nanoparticle-modified electrode. J. AOAC Int., 91, 2821-2825. 

Injang et al. [118] have developed a fast method for the simultaneous determination of Pb ", Cd +, and Zn + in herb samples by association of SIA with anodic stripping voltammetry. A bismuth film on the screen-printed carbon nanombes was prepared in situ and used as working electrode. Using a flow rate of 12 pi s low detection limits (0.2 pg 1 for Pb, 0.8 pg for Cd and 11 pg 1 for Zn) were achieved. 

A commonly encountered combination of metals in water is lead and copper, both being present as impurities due to the water having passed through pipes made from these two metals. Recently, Prado et al., reported the simultaneous detection of lead and copper in aqueous solution using anodic stripping voltammetry (ASV) at BDD [38]. Voltammetry and AFM imaging were used to show that. 

---