DIGESTION-FREE DETERMINATION OF HEAVY-METALS (PH, CD, CU) IN HONEY USING ANODIC-STRIPPING DIFFERENTIAL-PULSE VOLTAMMETRY AND POTENTIOMETRICSTRIPPING ANALYSIS

Experiments have been carried out to assess the potential of different ial pulse voltammetry and potential stripping analysis for determining Pb, Cu and Cd directly in dissolved honey samples using a flow-throug h cell. With the hanging mercury drop electrode Pb alone can be determ ined only if the electrode is first modified in-situ with Triton X 100 to increase the separation between the Pb peak and a broad, interferi ng adsorption peak which overlaps the Cu peak. If the (more sensitive) thin film mercury electrode is used the interference encountered is l ess so also Cu and Cd can be determined. With potentiometric stripping analysis Cu and Pb can be determined using normal procedures. The det ermination of Cd, however, can only be carried out if the concentratio n of the oxidizing agent [Hg(II)] in solution is decreased. A good agr eement has been obtained between the values found and those obtained a fter high pressure digestion of the samples.