In most electrolytes the peak potentials of lead and tin are so close together that a voltammetric determination is impossible. Difficulties occur especially if one of the metals is present in excess. Method 1 describes the determination of Pb and Sn. Differential pulse anodic stripping voltammetry (DPASV) is used under addition of cetyltrimethylammonium bromide. This method is used when:
- one is mainly interested in Pb
- Pb is in excess
- the Sn:Pb ratio is not higher than 200:1
According to method 1, Sn and Pb can be determined simultaneously if the difference in the concentrations is not too high and Cd is absent.
Method 2 is applied when traces of Sn and Pb are found or interfering TI and/or Cd ions are present. This method also uses DPASV in an oxalate buffer with methylene blue addition.
Method 3 in this Bulletin describes the determination of Sn(II) in presence of Sn(IV) by DPASV. Using an electrolyte containing fluoride, Sn(IV) gives no signal, so that a speciation is possible.