Single Sweep Polarographic Determination of Germanium in Medlar Using Its Heteropoly Acid Complex

In about 0.15 mol/L HCl solution containing ascorbic acid, GeO 2- 3 can rapidly react with molybdate. The reaction product can be reduced with a sensitive wave at the E p of about -1.05 V(vs.SCE) in NH 3 NH 4Cl buffer solution(pH=8.9). The second derivative peak height is proportional to the Ge concentration in the range of 6.9×10 -8 ～5.5×10 -5 mol/L with the detection limit of 3.5×10 -8 mol/L. The method is applied to the determination of germanium in medlar with satisfactory results. The behavior of polarographic wave has also been studied.