Determination of cadmium (II) and zinc (II) in olive oils by derivative potentiometric stripping analysis / LO COCO F; CECCON L; CIRAOLO L; NOVELLI V. -In: FOOD CONTROL. -ISSN 0956-7135. -14(2003), pp. 55-59. OriginalDetermination of cadmium (II) and zinc (II) AbstractA method for the determination of cadmium(II) and zinc(II) in olive oils by derivative potentiometric stripping analysis after dry ashing of the sample is described. The metal ions were concentrated as their amalgams on the glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE À1 , and E was plotted vs. dt dE À1 , thus increasing sensitivity of the method and improving resolution of the analysis. Quantitative analysis was carried out by the method of standard additions; a good linearity was obtained in the range of concentrations examined. Recoveries of 92-102% for cadmium(II) and of 89-99% for zinc(II) were obtained from an olive oil spiked at different levels. The detection limits were 5.1 ng g À1 for cadmium(II) and 7.6 ng g À1 for zinc(II) and the relative standard deviations (mean of nine determinations) were 4.1% and 5.2%, respectively. Results obtained on commercial olive oils were not significantly different from those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES).

High performance liquid chromatographic determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in honey / LO COCO F.; VALENTINI C.; NOVELLI V.; CECCON L. -In: JOURNAL OF CHROMATOGRAPHY A. -ISSN 0021-9673. -749(1996), pp. 95-102. OriginalHigh performance liquid chromatographic determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in honey AbstractA method of determination of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in honey by highperformance liquid chromatography (HPLC) is described. The method is based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives of carbonyl compounds is thus avoided and direct injection of the sample into the HPLC system is allowed. The procedure offers a high specificity, since the derivatives of F and HMF are well separated from the other components of the mixture under examination. Recoveries of 95-99% were obtained from honey spiked at different levels with both analytes. The detection limit is of the order of 10/zg/kg of honey and reproducibility (mean of six determinations) is -+3% for F and +_2% tbr HMF.

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