Diamond paste based electrodes for the determination of Pb(II) at trace concentration levels.

Three types of monocrystalline diamond: natural diamond 1mum, synthetic diamond 50mum (synthetic-1), and synthetic diamond 1mum (synthetic-2) were used for electrodes' construction. The linear concentration ranges recorded for Pb(II), when natural diamond, synthetic-1 and synthetic-2 based electrodes were used were between 10(-9) and 10(-6); 10(-10) and 10(-7); and between 10(-10) and 10(-8)moll(-1), respectively. Low detection limits which lie between 10 and 100pmoll(-1) proves the sensitivity of the electrodes. It was found that Pb(II) yielded a peak at about +0.3+/-0.02V (versus Ag/AgCl) for all the electrodes. Lead was determine with high reliability from water and tea samples at trace concentration levels using the proposed diamond paste based electrodes.