Chemical Speciation Of Binary Complexes of Pb(II), Cd(II) and Hg(II) With L-Dopa in Dimethylformamide-Water Mixture


  • Aditya Deepthi D School of chemistry, Andhra University, Visakhapatnam 530003, India
  • Prasanthi J School of chemistry, Andhra University, Visakhapatnam 530003, India
  • Nageswara Rao G School of chemistry, Andhra University, Visakhapatnam 530003, India


L-dopa, dimethylformamide, MINIQUAD75, electrostatic forces, electrostatic forces


Equilibrium study on complex formation of L-Dopa with Pb(II), Cd(II), and Hg(II) has been investigated pH metrically in dimethylformamide-water mixtures (0–60% v/v) at 303 K and 0.16 mol L?1 ionic strength. The predominant species detected for Pb(II) and Hg(II) are MLH2 and ML2H and those for Cd(II) are MLH, ML2H, MLH2. The appropriateness of experimental conditions was verified by introducing errors intentionally in the concentrations of ingredients. The models containing different numbers of species were refined by using the computer program MINIQUAD75. The best-fit chemical models were arrived at based on statistical parameters. The trend in variation of stability constants of the complexes with dielectric constant of the medium is attributed to the electrostatic and non electrostatic forces. The species distribution and the plausible equilibria for the formation of the species are also presented.


Download data is not yet available.


Freitag CM. The genetics of autistic disorders and its clinical relevance: a review of the litera-ture.Molecular Psychiatry 2007; 12: 2-12.

Manay N et al. Lead contamination in Uruguay: the "La Teja" neighborhood case. Rev. Environ. Contamin. Toxicology 2008; 95: 93-102.

White L D et al. New and evolving concepts in the neurotoxicology of lead. Toxicology and Applied Pharmacology 2007; 225: 1-5.

Flora S J et al. Heavy metal induced oxidative stress & its possible reversal by chelation therapy. Indian Journal of Medical Research 2008; 128: 501-508.

Filipi M et al. Molecular mechanisms of cadmium induced mutagenicity. Human and Experimental Toxicology 2006; 25: 67-69.

Jarup Br. L. Hazards of heavy metal contamination. Medical Bulletin 2003; 68: 167 -170.

Bertin G and Averbeck D. Cadmium: cellular effects, modifications of biomolecules, modulation of DNA repair and genotoxic consequences (a review). Biochimie 2006; 88: 1549-1555.

Wagner G J. Effects of Buthionine Sulfoximine on Cd-Binding Peptide Levels in Suspension- Cultured Tobacco Cells Treated with Cd, Zn, or Cu. Plant Physiology 1984; 76: 797-804.

Steffens J C. Heavy metal detoxification in higher plants (a review). Molecular Biology 1990; 41: 553-557.

Cobbett C S and Goldsbrough P B. Mechanisms of metal resistance: Phytochelatins and metallothioneins. In Phytoremediation of Toxic Metals Using Plants to Clean up thEnvironment. Eds, I. Raskin and B. D. Ensley,John Wiley and Sons Inc. NY 1999; p 247.

Li Z et al. Ionic Liquid as Novel Solvent for extraction and separation in analytical chemistry. Talanta 2007; 71: 68-72.

Ashkenani H. Preconcentration, speciation and determination of ultra-trace amounts ofmercury by modified octadecyl silica membrane disk/electron beam irradiation and cold vapor atomic absorption spectrometry. Journal of Hazard Mater 2009; 161: 276-280.

W. Birkmayer, O. Horneykiewicz, Wien. Klin. Wschr, 1961,73, 787–788.

O. Horneykiewicz, Wien. Klin. Wschr, 1963, 75, 309–312.

Sengwa R J et al. Static permittivity and molecular interactions in binary mixtures of ethanolamine with alcohols and amides. Molecular Physics 2001; 21: 805-808.

Sigel H et al. An Estimation of the Equivalent Solution Dielectric Constant in the Active-Site Cavity of Metalloenzymes. Dependence of Carboxylate-Metal-Ion Complex Stabilities on the Polarity of Mixed Aqueous/Organic Solvents. European Journal of Biochemistry 1985; 152: 187-194.

Aditya Deepthi D ,Prasanthi J and Nageswara Rao G. Int. J. Adv. Res. 5(2), 1862-1869,2017.

Gran G. Determination of the equivalence points in potentiometric titrations-Part-II. Analyst 1952; 77: 661-671.

. Gran G. Equivalence volumes in potentiometric titrations. Analytica Chimica Acta 1988; 206:111-123.

Sailaja B B V et al. Effect of micelles on speciation of ternary complexes of Uranyl(VI) with oxalic and malonic acids. The Proceedings of the National Academy of Sciences, India 2004; 74: 399-412.

Raju S et al. Speciation of binary complexes of L-glutamic acid with Co(II), Ni(II) and Cu(II) in low dielectric media. Journal of Indian Chemical Society 2012; 89: 57-62.

Rao G N. Ph.D. Complex equilibria of some biologically important metal ions in aquoorganic media Thesis, Andhra University, Visakhapatnam. India 1989.

Gans P et al. An improved computer program for the computation of formation constants from potenti-ometric data. Inorganica Chimica Acta 1976; 18: 237-239.

Rao G N et al. Computer augmented modeling of complexes of amino acids in aqua-organic mixtures. Journals of the Indian Chemical Society 1991; 68: 34-42.

Latha M P et al. Determination of protonation constants of L-glutamic acid and L-methionine in 1, 2- propanediol-water mixtures. Acta Chimica Slovenica 2007; 54: 160-165.

Born M Volume and hydration heat of ions. Z. Phys 1920; 1: 45-47.


13 Views | 12 Downloads

How to Cite

Aditya Deepthi D, Prasanthi J, and Nageswara Rao G. “Chemical Speciation Of Binary Complexes of Pb(II), Cd(II) and Hg(II) With L-Dopa in Dimethylformamide-Water Mixture”. International Journal of Pharmaceutics and Drug Analysis, vol. 5, no. 5, May 2017, pp. 185-92,



Research Articles
Share |