Adsorption differential pulse voltammetry

Electrochemical preconcentration can be achieved in the following two different ways, depending on whether differential pulse stripping voltammetry (differential pulse ASV) or adsorption differential pulse voltammetry has been applied. 

ADPV Adsorption differential pulse voltammetry SETAAS slurry ETAAS SDCP direct slurry DCP... 

Methods for quantitative analysis of Co indude flame and graphite-furnace atomic absorption spectrometry (AAS e.g., Welz and Sperling 1999), inductively coupled plasma emission spectrometry (ICP-AES e.g., Schramel 1994), neutron activation analysis (NAA e.g., Versieck etal. 1978), ion chromatography (e.g., Haerdi 1989), and electrochemical methods such as adsorption differential pulse voltammetry (ADPV e.g., Ostapczuk etal. 1983, Wang 1994). Older photometric methods are described in the literature (e.g.. Burger 1973). For a comparative study of the most commonly employed methods in the analysis of biological materials, see Miller-Ihli and Wolf (1986) and Angerer and Schaller... 

L. Ilcheva and K. Cammann, Flow Injection Analysis of Chloride in Tap and Sewage Water Types by Adsorption Differential Pulse Voltammetry. Fresenius Z. Anal. Chem., 322 (1985) 323. 

Gammelgaard, B. and Andersen, J.R. (1985). Determination of nickel in human nails by adsorption differential-pulse voltammetry. Analyst, 110,1197. 

L. Fernandez-Llano, M.C. Blanco-Lopez, M.J. Lobo-Castanon, A.J. Miranda-Ordieres and P. Tunon-Blanco, Determination of diclofenac in urine samples by molecularly-imprinted solid-phase extraction and adsorptive differential pulse voltammetry. Electroanalysis, 19 (15) 1555-1561,2007. 

The adsorption behavior of the psychotropic drug flunitrazepam (256) at the hanging mercury drop electrode was studied by staircase voltammetry and by adsorptive stripping differential pulse voltammetry. 256 can be determined down to nanomolar levels by using adsorptive preconcentration prior to the differential pulse voltammetry scan. The method was applied to determination of 256 in human urine530. 

Differential pulse voltammetry is particularly susceptible to adsorption of species on the electrode, which can have drastic implications for peak shape. If adsorption is suspected, then peak area should be used rather than peak height... 

Differential pulse voltammetry and electrochemical impedance have demonstrated that G, A, guanosine, and their oxidation products are electrostatically adsorbed on GC and GC(ox) surfaces [47,49]. The strength of adsorption of the DNA bases on the GC surface were found to be similar [49]. Strongly adsorbed G dimers were formed on GC between G and the adsorbed G oxidation products, which slowly cover and block the surface. The appHcation of ultrasound led to removal of the adsorbed species. The effect of this was mainly to enhance transport of electroactive species and to clean the electrode in situ, avoiding electrode fouling. 

Recent studies describe the use of cyclic voltammetry in conjunction with controlled-potential coulometry to study the oxidative reaction mechanisms of benzofuran derivatives [115] and bamipine hydrochloride [116]. The use of fast-scan cyclic voltammetry and linear sweep voltammetry to study the reduction kinetic and thermodynamic parameters of cefazolin and cefmetazole has also been described [117]. Determinations of vitamins have been studied with voltammetric techniques, such as differential pulse voltammetry for vitamin D3 with a rotating glassy carbon electrode [118,119], and cyclic voltammetry and square-wave adsorptive stripping voltammetry for vitamin K3 (menadione) [120]. 

Electrochemical measurements have been developed by using different electrochemical techniques (differential pulse voltammetry (DPV), cyclic voltametry (CV), potentiometric stripping analysis (PSA), square wave voltammetry (SWV), adsorptive stripping transfer voltammetry (ASTV), etc.). The abbreviations given in covalent attachment of DNA onto different transducers are water soluble carbodimide l-(3-dimethyaminopropyl)-3-ethyl-carbodimide (EDC), IV-hydroxysuccimide (NHS), mercaptohexanol (MCH), aminoethanethiol (AET), mercaptosilane (MSi), and N-cyclohexyl-lV -[2-(N-methylmorpholino)-ethyl]carbodimide-4-tolune sulfonate (CDS). 

Far from the metal trace analysis, our initial studies with BCFMEs were focused on the determination of folic acid [122], In this case, the main goal was the optimisation of the electrode pretreatment for this analyte. An acidic medium (0.1M perchloric acid) was considered optimum for folic acid determination by differential pulse voltammetry. A linear range between 2.0 x HT8 and 1.0 x 10 6M with a detection limit of 1.0 x 10 8M was obtained. Nevertheless, in this work, the adsorptive properties of the folic acid on mercury were noted and the employment of mercury-coated carbon fibre UMEs for folic acid determination has been targeted as a future goal. 

ADPCSV Adsorptive differential pulse cathodic stripping voltammetry... 

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... 

Distinguish between (a) voltammetry and amperometry, (b) linear-scan voltammetry and pulse voltammetry, (c) differential-pulse voltammetry and square-wave voltammetry, (d) an RDE and a ring-disk electrode, (e) faradaic impedance and double-layer capacitance, (f) a limiting current and a diffusion current, (g) laminar flow and turbulent flow, (h) the standard electrode potential and the half-wave potential for a reversible reaction at a working electrode, (i) normal stripping methods and adsorptive stripping methods. 

Square-wave voltammetry (SWV) is one of the four major voltammetric techniques provided by modern computer-controlled electroanalytical instruments, such as Autolab and pAutolab (both EcoChemie, Utrecht), BAS 100 A (Bioana-lytical Systems) and PAR Model 384 B (Princeton Applied Research) [1], The other three important techniques are single scan and cyclic staircase, pulse and differential pulse voltammetry (see Chap. II.2). All four are either directly applied or after a preconcentration to record the stripping process. The application of SWV boomed in the last decade, firstly because of the widespread use of the instruments mentioned above, secondly because of a well-developed theory, and finally, and most importantly, because of its high sensitivity to surface-confined electrode reactions. Adsorptive stripping SWV is the best electroanalytical method for the determination of electroactive organic molecules that are adsorbed on the electrode surface [2]. 

Another way to immobilize DNA by adsorption on an electrochemical transducer has been described [44,45]. In this case, the DNA biosensor was prepared by dipping a GCE in a DNA solution and leaving the electrode to dry. This sensor was then used to preconcentrate nitroimidazole [44] or mitoxantrone [45] on the surface and to study the interaction mechanism of these drugs with DNA by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square-wave voltammetry (SWV). 

Oliveira Brett AM, da Silva LA, Brett CMA (2002) Adsorption of guanine, guanosine and adenine at electrodes studied by differential pulse voltammetry and electrochemical impedance. Langmuir 18 2326-2330... 

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