Differential pulse voltammetry analyses

Differential pulse voltammetry has been widely used for in vivo electrochemical analysis This technique combines the linear sweep and pulsed potential... 

Differential pulse voltammetry provides greater voltammetric resolution than simple linear sweep voltammetry. However, again, a longer analysis time results from the more sophisticated potential waveform. At scan rates faster than 50 mV/sec the improved resolution is lost. Because it takes longer to scan the same potential window than by linear sweep, an even longer relaxation time between scans is required for differential pulse voltammetry. 

Competitive immunoassays may also be used to determine small chemical substances [10, 11]. An electrochemical immunosensor based on a competitive immunoassay for the small molecule estradiol has recently been reported [11]. A schematic diagram of this immunoassay is depicted in Fig. 5.3. In this system, anti-mouse IgG was physisorbed onto the surface of an SPCE. This was used to bind monoclonal mouse anti-estradiol antibody. The antibody coated SPCE was then exposed to a standard solution of estradiol (E2), followed by a solution of AP-labeled estradiol (AP-E2). The E2 and AP-E2 competed for a limited number of antigen binding sites of the immobilized anti-estradiol antibody. Quantitative analysis was based on differential pulse voltammetry of 1-naphthol, which is produced from the enzymatic hydrolysis of the enzyme substrate 1-naphthyl phosphate by AP-E2. The analytical range of this sensor was between 25 and 500pg ml. 1 of E2. 

Other techniques that have been used include subtractive differential pulse voltammetry at twin gold electrodes [492], anodic stripping voltammetry using glassy-carbon electrodes [495,496], X-ray fluorescence analysis [493], and neutron activation analysis [494],... 

Shuman LM. Differential pulse voltammetry. In Bartels JM (ed.), Methods of Soil Analysis Part 3 Chemical Methods. Madison, WI Soil Science Society of America and American Society of Agronomy 1996, pp. 247-268. 

Wang and Dewald have investigated the possibility of using rapid scan differential pulse voltammetry for the detection of chlorpromazine in flow-injection analysis [160]. The measurement was made with the use of a flow-cell equipped with a carbon paste or a vitreous-carbon disc electrode, a carbon rod auxiliary electrode, and a silver-silver chloride reference electrode. Potential scanning was effected at 2 V/min. 

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. 

SPMBE = screen-printed microband electrode, ASV = anodic stripping voltammetry, HCMV = human cytomegalovirus, PGE = pencil-graphite electrode, DPV = differential pulse voltammetry, SPEs = screen-printed electrodes, PSA = potentiometric stripping analysis, M-GECE = magnetic graphite-epoxy composite electrode. 

Choose differential pulse voltammetry (DPY) analysis mode in the Autolab software program. 

Cyclic Voltammetry. However, experimental use of this technique has been restricted almost exclusively to the analysis of the limiting currents of the signals obtained. One reason for this could be that when a quasi-reversible electronic transfer is analyzed in RPV, two very close waves are obtained, which are difficult to resolve from an experimental viewpoint. This problem can be eliminated by using the triple pulse technique Reverse Differential Pulse Voltammetry (RDPV), proposed in references [80, 84, 85] and based in the application of the waveform presented in Scheme 4.5. 

Radi [41] used an anodic voltammetric assay method for the analysis of omeprazole and lansoprazole on a carbon paste electrode. The electrochemical oxidations of the drugs have been studied at a carbon paste electrode by cyclic and differential-pulse voltammetry in Britton-Robin-son buffer solutions (0.04 M, pH 6-10). The drug produced a single oxidation step. By differential-pulse voltammetry, a linear response was obtained in Britton-Robinson buffer pH 6 in a concentration range from 2 x 10-7to 5 x 10 5 M for lansoprazole or omeprazole. The detection limits were 1 x 10 8 and 2.5 x 10 8 M for lansoprazole and omeprazole, respectively. The method was applied for the analysis of omeprazole in capsules. The results were comparable to those obtained by spectrophotometry. 

Ballantine, J. Woolfson, A.D. The application of differential pulse voltammetry at the glassy carbon electrode to multivitamin analysis. J. Pharm. Pharmacol. 1980, 32, 353-356. 

Electrochemical biosensors have some advantages over other analytical transducing systems, such as the possibility to operate in turbid media, comparable instrumental sensitivity, and possibility of miniaturization. As a consequence of miniaturization, small sample volume can be required. Modern electroanalytical techniques (i.e., square wave voltammetry, chronopotentiometry, chronoamperometry, differential pulse voltammetry) have very low detection limit (1(T7-10 9 M). In-situ or on-line measurements are both allowed. Furthermore, the equipments required for electrochemical analysis are simple and cheap when compared with most other analytical techniques (2). Basically electrochemical biosensor can be based on amperometric and potentiometric transducers, even if some examples of conductimetric as well as impedimetric biosensor are reported in literature (3-5). 

ROMANI A, MINUNNI M, MULINACCI N, PINELLI P and VINCIERI E F (2000), Comparison among differential pulse voltammetry, amperometrie biosensor, and HPLC/DAD analysis for polyphenol determination , J... 

Figure 11.8.5 Anodic stripping analysis of a solution containing 2 X 10 M Zn, Cd, Pb, and Cu at an MFE (mercury-plated, wax-impregnated graphite electrode). Stripping carried out by differential pulse voltammetry.

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. 

Figure 3.3 Electrochemical aptasensor for thrombin based on the control of electron transfer between redox-labeled aptamer and the electrode. (A) Controlling the orientation of the redox label with respect to the electrode upon formation of a thrombin-aptamer complex. (B) Differential pulse voltammetry corresponding to an analysis of different concentrations of thrombin by a ferrocene-tethered aptamer (a) 0, (b) 10, (c) 20, and (d) 30 nM. (Reprinted with permission from Radi et al., 2006. Copyright 2006 American Chemical Society.) (C) Activation of the electrical contact of methylene blue-tethered aptamer upon formation of the respective aptamer-thrombin complex. (D) Voltammo-grams corresponding to analysis of the thrombin by the configuration depicted in part (C) curves (a) no thrombin (b) thrombin 10 nM (c) thrombin 256 nM. (Reprinted with permission from Xiao et al., 2005. Copyright 2005 American Chemical Society.) (E) Blocking the electrical response of methylene blue intercalated into the stem of a DNA hairpin as a result of formation of an aptamer-thrombin complex.

Besides these potentiometric-based methods, a series of electrochemical techniques can be applied to the detection of biomolecular interactions. Depending on the desired dynamic detection range and the specific properties of the system under study, techniques such as electrochemical impedance spectroscopy, voltage step capacitance measurements, amperometry, differential pulse voltammetry, square wave voltammetry, AC voltammetry, and chronopotentiomet-ric stripping analysis can be used for label-free detection of DNA, proteins, and peptides [1]. Often these techniques require the use of redox mediators. Electrochemical impedance spectroscopy (EIS), in particular, is a very promising technique for DNA biosensing [2,3]. 

The electrochemical signals of nucleic acid bases were shown to have insufficient sensitivity for DNA analysis in the 1960s, because of the poorly developed detection devices without software systems. However, recent advancements in this field started with digital potentiostats and sophisticated baseline correction techniques in connection with differential pulse voltammetry (DPV) [9] and square wave voltammetry (SWV) [10-12]. Therefore, well-defined voltammetric peaks have been obtained from DNA or RNA at carbon electrodes in the last decade [13],... 

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