Determination of trace heavy metals in herbs by sequential injection analysis-anodic stripping voltammetry using screen-printed carbon nanotubes electrodes.

A method for the simultaneous determination of Pb(II), Cd(II), and Zn(II) at low microg L(-1) concentration levels by sequential injection analysis-anodic stripping voltammetry (SIA-ASV) using screen-printed carbon nanotubes electrodes (SPCNTE) was developed. A bismuth film was prepared by in situ plating of bismuth on the screen-printed carbon nanotubes electrode. Operational parameters such as ratio of carbon nanotubes to carbon ink, bismuth concentration, deposition time and flow rate during preconcentration step were optimized. Under the optimal conditions, the linear ranges were found to be 2-100 microg L(-1) for Pb(II) and Cd(II), and 12-100 microg L(-1) for Zn(II). The limits of detection (S(bl)/S=3) were 0.2 microg L(-1) for Pb(II), 0.8 microg L(-1) for Cd(II) and 11 microg L(-1) for Zn(II). The measurement frequency was found to be 10-15 stripping cycle h(-1). The present method offers high sensitivity and high throughput for on-line monitoring of trace heavy metals. The practical utility of our method was also demonstrated with the determination of Pb(II), Cd(II), and Zn(II) by spiking procedure in herb samples. Our methodology produced results that were correlated with ICP-AES data. Therefore, we propose a method that can be used for the automatic and sensitive evaluation of heavy metals contaminated in herb items.

[1]  Yoshiaki Furusho,et al.  Determination of Cr(VI) by Solid-Phase Extraction with Highly Selective Resin , 2009 .

[2]  I. Varga,et al.  Determination of trace metals and speciation of chromium ions in atmospheric precipitation by ICP-AES and GFAAS. , 1994, Talanta.

[3]  Hao Yu,et al.  Adsorption characteristic of acidified carbon nanotubes for heavy metal Pb(II) in aqueous solution , 2007 .

[4]  G. G. Muntyanu,et al.  Electroanalytical Properties of a Thin-Film Mercury–Carbon Electrode of Subnanometric Thickness in High-Speed Linear-Sweep Anodic Stripping Voltammetry as Exemplified by the Determination of Zn(II), Cd(II), and Pb(II) , 2004 .

[5]  M. Mascini,et al.  An optimized digestion method coupled to electrochemical sensor for the determination of Cd, Cu, Pb and Hg in fish by square wave anodic stripping voltammetry. , 2009, Talanta.

[6]  César Ricardo Teixeira Tarley,et al.  Simultaneous determination of zinc, cadmium and lead in environmental water samples by potentiometric stripping analysis (PSA) using multiwalled carbon nanotube electrode. , 2009, Journal of hazardous materials.

[7]  Yoshiaki Furusho,et al.  Advanced Solid Phase Extraction for Inorganic Analysis and Its Applications , 2008 .

[8]  M. Smyth,et al.  Validation of bismuth film electrode for determination of cobalt and cadmium in soil extracts using ICP-MS. , 2004, Talanta.

[9]  Hao Yu,et al.  Mechanism study on adsorption of acidified multiwalled carbon nanotubes to Pb(II). , 2007, Journal of colloid and interface science.

[10]  Y. Xian,et al.  Nafion‐Coated Bismuth Film Electrodes for the Determination of Trace Lead and Cadmium in Herbal Medicines by Anodic Stripping Voltammetry , 2008 .

[11]  Richard E. Smalley,et al.  Enhancement of adsorption inside of single-walled nanotubes: opening the entry ports , 2000 .

[12]  S. Arpadjan,et al.  Arsenic, cadmium and lead in medicinal herbs and their fractionation. , 2008, Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association.

[13]  R. Stefan,et al.  Chemical speciation by sequential injection analysis: an overview. , 2004, Talanta.

[14]  A. Economou,et al.  On-line stripping voltammetry of trace metals at a flow-through bismuth-film electrode by means of a hybrid flow-injection/sequential-injection system. , 2007, Talanta.

[15]  Lu,et al.  Bismuth-coated carbon electrodes for anodic stripping voltammetry , 2000, Analytical chemistry.

[16]  Guodong Liu,et al.  Ultrasensitive voltammetric detection of trace heavy metal ions using carbon nanotube nanoelectrode array. , 2005, The Analyst.

[17]  K. Pyrzyńska,et al.  Adsorption of heavy metal ions with carbon nanotubes , 2007 .

[18]  W. Dungchai,et al.  Determination of trace heavy metals by sequential injection-anodic stripping voltammetry using bismuth film screen-printed printed carbon electrode. , 2008, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.

[19]  A. Economou,et al.  Polymer-coated bismuth film electrodes for the determination of trace metals by sequential-injection analysis/anodic stripping voltammetry. , 2006, Analytica chimica acta.

[20]  Gil-Ho Hwang,et al.  Determination of trace metals by anodic stripping voltammetry using a bismuth-modified carbon nanotube electrode. , 2008, Talanta.

[21]  A. Economou,et al.  A study of bismuth-film electrodes for the detection of trace metals by anodic stripping voltammetry and their application to the determination of Pb and Zn in tapwater and human hair. , 2003, Talanta.

[22]  E. Hutton,et al.  Bismuth film electrode for anodic stripping voltammetric determination of tin. , 2006, Analytica chimica acta.

[23]  Jun Liu,et al.  Carbon nanotube-modified electrodes for the simultaneous determination of dopamine and ascorbic acid. , 2002, The Analyst.

[24]  M. Soylak,et al.  Cloud point extraction procedure for flame atomic absorption spectrometric determination of lead(II) in sediment and water samples , 2007 .

[25]  M. Soylak,et al.  Multi-element coprecipitation for separation and enrichment of heavy metal ions for their flame atomic absorption spectrometric determinations. , 2009, Journal of hazardous materials.