Calculate the concentration of cu:

Problem:

Anodic stripping voltammetry is used for the analysis of copper in a sea water sample using standard addition method. When a 50 ml sample is analysed it gave a peak current of 0.886 µ A. A 5.00 µ dm³ spike of 10 ppm Cu⁺⁺ is added to the sample and the resulting peak current is 3.52 µ A. Calculate the concentration of Cu⁺⁺ in ppm in the given sample of sea water.

Answer:

Peak current in anodic stripping voltammetry is proportional to the analyte concentration

i_p α Cu⁺⁺ (ppm)

i_p = k (Con. Cu⁺⁺)

where k is a constant

Thus for the sample 0.886 = k (con. Cu⁺⁺)

and for the standard solution

3.52 = k

[ 0.05 dm³ / 0.05 dm³ + 5 x10^-6 dm³(Con.Cu ^{+ +} ) +5.00×10^-6 dm³/0.05 dm³ + 5×10^-6 dm³(10 ppm )]

Solving the Eq. (1) for k and substituting in Eq. (2) the concentration of Cu⁺⁺ in the given sample of sea water comes out to 3.36 × 10^{- 4} ppm.