Voltammetry stripping peak current

Finally, the stripping procedure can also be applied to the interface between two immiscible electrolyte solutions [96]. By a proper polarization of the interface, a certain ion can be transferred from the sample solution into a small volume of the second solution. After this accumulation, the ion can be stripped off by linear scan voltammetry, or some other voltammetric technique. The stripping peak current is linearly proportional to the concentration of ions in the second solution and indirectly to the concentration of ions in the sample solution. The method is used for the determination of electroinactive ions, such as perchlorate anion [97]. The principles of the procedure are the same as in the case of faradaic reactions, and the differences arise from the particular properties of phenomena on the interface that are beyond the scope of this chapter. 

A monotonic increase in the stripping peak current was observed with increasing concentration (Fig. 16.5). The linearity observed here and in previous studies on Pb validates the potential usefulness of this technique for quantification. A concentration of 4 X 10 M was detected with different measurement conditions (Fig. 16.6), specifically, linear sweep voltammetry (LSV) instead of DPV. Three differences in the two experimental results should be noted. First, although the peak potentials are similar (-0.53 to 0.51 V in... 

Our group also used diamond RDE electrodes for the determination of lead. The use of rotating electrodes showed that a factor of ca. 10 enhancement in the stripping current was realized. Linear sweep voltammetry curves for 2 nM lead solution using a RDE are shown in Fig. 16.16. The increase in the stripping peak current is evident with an increase in the rotation speed [45]. 

The concentration of copper in a sample of sea water is determined by anodic stripping voltammetry using the method of standard additions. When a 50.0-mL sample is analyzed, the peak current is 0.886 )J,A. A 5.00-)J,L spike of 10.0-ppm Cu + is added, giving a peak current of 2.52 )J,A. Calculate the parts per million of copper in the sample of sea water. 

Peak currents in anodic stripping voltammetry are a linear function of concentration... 

Precision Precision is generally limited by the uncertainty in measuring the limiting or peak current. Under most experimental conditions, precisions of+1-3% can be reasonably expected. One exception is the analysis of ultratrace analytes in complex matrices by stripping voltammetry, for which precisions as poor as +25% are possible. 

X f0 ppb Sb was added, anodic stripping voltammetry is repeated, giving a peak current of f.i4 pA. How many nanograms of Sb is collected from the individual s hand ... 

Voltaic cells 64. 504 Voltammetry 7, 591 anodic stripping, 621 concentration step, 621 mercury drop electrode, 623 mercury film electrode, 623 peak breadth, 622 peak current, 622 peak potential, 622 purity of reagents, 624 voltammogram, 622 D. of lead in tap water, 625 Volume distribution coefficient 196 Volume of 1 g of water at various temperatures, (T) 87... 

Early work [400] on the application of cyclic and anodic stripping voltammetry to the determination of lead showed a poor correlation between peak current values and Pb11 concentration at high pH values. This is due to the low electrochemical activity of PbOH. 

After tq is passed, the second step starts by scanning the potential from Ed to a potential when all the deposited metals are re-oxidized (the reverse of reaction 25). The oxidation current recorded as a function of potential is the anodic stripping voltammogram (ASV). A typical ASY of three metals (Cd, Pb, and Cu) deposited on a mercury film electrode is shown in Fig. 18b.12b. The sensitivity of ASY can be improved by increasing the deposition time and by using the pulse technique to record the oxidation current. ASV in Fig. 18b. 12b was obtained by using the square wave voltammetry. In most cases a simple linear or step ramp is sufficient to measure sub-ppm level of metals in aqueous solution. The peak current of a linear scan ASV performed on a thin mercury film electrode is given by... 

Fig. 3.14 Anodic stripping square-wave voltammetry (ASSWV) of 1 X 10- M Dependence of peak currents on the accumulation time, itacc = —0.8 V, tacc = 5 s. (1) organic carbon-free water and (2) double-distilled water contaminated by unknown surfactant. Additions of Triton X-100 to (2) inmg/1 (3) 0.1, (4) 0.3, (5) 0.5, (6) 0.8 and (7) 1. Esv/ = 30 mV, / = 100 Hz and AE = 2.4 mV (reprinted from [247] with permission)...

Method 2 -An adsorptive stripping method also involving pulse voltammetry, which yielded a peak current that was proportional to the concentration of chlorpromazine in the range of 83 to 2000 nM. 

The effectiveness of glassy-carbon electrodes coated with cellulose acetate for adsorptive stripping voltammetry was evaluated to alleviate interference from co-adsorbed species [171]. The carbon electrode was coated using a 5% cellulose acetate solution, with the coating being hydrolyzed with 0.07M potassium hydroxide. Repetitive measurements of 1 pM chlorpromazine in the presence of 20 mg/L albumin resulted in peak currents with residual standards of deviation equal to 1.4 and 1.3%, respectively. 

At the hanging mercury drop electrode, not all the metal is stripped during the potential scan. The peak current for differential pulse stripping voltammetry at the hanging mercury drop electrode is proportional to the pulse amplitude AE [6] ... 

Fig. 14.27 Automated adsorptive stripping voltammetry (AdSV) of Ni2+ ions (a) calibration plot derived from the peak current of DPVs of automated AdSV using the standard addition method (b) Long-term Ni2+ ions release from surfaces of electropolished NiTi shape memory alloys kept in NaCl solution. NaCl concentrations were either 15wt.% solid line) or 0.9wt.% dotted line).78 (Reproduced by permission of Wiley-VCH Verlag GmbH Co KGaA)...

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