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RESEARCH PRODUCT

Polarographic determination of glycine with a dropping copper amalgam electrode

subject

description

The anodic oxidation of a dropping copper amalgam electrode in presence of dilute solutions of glycine in 0.50 M NaClO4 has been studied. An anodic wave at −0.28V (SCE) is observed, yielded by diffusion of glycinate anion in the solution towards the electrode surface. The wave-heights increase with the glycinate concentration (function of glycine concentration and pH value) until the anodic oxidation is controlled by the metal diffusion into mercury. The effect of pH is interpreted by attributing it to the depolarizer effects at glycinate anion even though the zwitterion is present in much larger concentrations. The applicability of anodic oxidation of a dropping copper amalgam electrode in the determination of glycine in the range of concentrations 10−4–10−2 M with a rigorous control of pH (8.0<pH<10.5) is shown. The standard deviation of the proposed method is 4.1% and the minimum concentration determinable is in the 1×10−4 M range.