A method for the determination of cadmium and lead in vegetables by stripping chronopotentiometry, after digestion of the sample with concentrated sulphuric acid and dry-ashing, is described. Metal ions were concentrated as their amalgams on a glassy carbon-working electrode previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally derived and E was plotted versus dt/dE, thus increasing both the sensitivity of the method and the resolution of the analysis. Quantitative analysis was carried out by the method of standard additions; a good linearity was obtained in the range of examined concentrations, as was shown by the determination coefficients, which were 0.998 (n= 4) for cadmium and 0.993 (n= 4) for lead. Recoveries of 85–100% for cadmium and of 84–97% for lead were obtained from a sample spiked at different levels. Accuracy was demonstrated by analysis of a matching reference sample of cabbage. The detection limits were 1.8 ng/g of wet mass for cadmium and 5.1 ng/g of wet mass for lead. The relative standard deviations (mean of nine determinations), evaluated on a real sample, were 6.7 and 6.2%, respectively. Results obtained on 10 different commercial samples of pepper (Capsicum annuum) and egg plant (Solanum melongena) were not significantly different from those obtained by graphite furnace atomic absorption spectrophotometry. The average content was in the range 3.1–18.6 ng/g for cadmium and 38.2–64.3 ng/g for lead.

Determination of Cadmium and Lead in Vegetables by Stripping Chronopotentiometry

LO COCO, Filippo;NOVELLI, Veronica;CECCON, Luciano;
2004

Abstract

A method for the determination of cadmium and lead in vegetables by stripping chronopotentiometry, after digestion of the sample with concentrated sulphuric acid and dry-ashing, is described. Metal ions were concentrated as their amalgams on a glassy carbon-working electrode previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally derived and E was plotted versus dt/dE, thus increasing both the sensitivity of the method and the resolution of the analysis. Quantitative analysis was carried out by the method of standard additions; a good linearity was obtained in the range of examined concentrations, as was shown by the determination coefficients, which were 0.998 (n= 4) for cadmium and 0.993 (n= 4) for lead. Recoveries of 85–100% for cadmium and of 84–97% for lead were obtained from a sample spiked at different levels. Accuracy was demonstrated by analysis of a matching reference sample of cabbage. The detection limits were 1.8 ng/g of wet mass for cadmium and 5.1 ng/g of wet mass for lead. The relative standard deviations (mean of nine determinations), evaluated on a real sample, were 6.7 and 6.2%, respectively. Results obtained on 10 different commercial samples of pepper (Capsicum annuum) and egg plant (Solanum melongena) were not significantly different from those obtained by graphite furnace atomic absorption spectrophotometry. The average content was in the range 3.1–18.6 ng/g for cadmium and 38.2–64.3 ng/g for lead.
File in questo prodotto:
File Dimensione Formato  
2004 Food Additives and Contaminants.pdf

non disponibili

Tipologia: Versione Editoriale (PDF)
Licenza: Non pubblico
Dimensione 171 kB
Formato Adobe PDF
171 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/877454
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 4
social impact