Статья
2021

Quantitative Evaluation of Generic Glyphosate Using Carbon Paste Electrode Electrochemically Modified with Copper Ions


 Youssef Ibrahim Moharram Youssef Ibrahim Moharram , Ibrahim Shibl El-Hallag Ibrahim Shibl El-Hallag , Sameh Mahmoud Selim Sameh Mahmoud Selim
Российский электрохимический журнал
https://doi.org/10.1134/S1023193520120150
Abstract / Full Text

Abstract

Generic products are not identical to their branded equivalents. They are typically off-patent. Therefore, this paper suggests a selective, reliable, and accurate electrochemical method for quantifying the original and generic glyphosate from Monsanto Roundup®—USA and Rotam Agrochemicals—Hong Kong. The reliability of the suggested electroanalytical method was assured. An electrochemically modified carbon paste electrode was used as a working electrode. This working electrode was constructed by depositing a copper layer electrochemically using chronoamperometry under continuous stirring. The copper deposition was conducted for 180 s at the potential of –0.8 V from an aqueous solution of copper sulphate pentahydrate at pH 6.5. Adjust by adding phosphate buffer. Cyclic voltammograms for electrochemically modified CPE versus Ag/AgCl were recorded between (–0.8…–1.4 V) at a scan rate of 0.1 V s–1 in solutions with and without glyphosate. The results showed an enhancing in the oxidation peak current of the copper previously deposited on CPE by the addition of glyphosate. This enhancing in copper oxidation peak may be attributed to glyphosate adsorption on the surface of the electrode and formation of a complex. SW-ASV method was used as an efficient electroanalytical technique for glyphosate quantification. The operating parameters such as accumulation potential and accumulation time were optimized to give maximum oxidation peak current of copper. Calibration curves were constructed in a concentration range (2 × 10–6–2 × 10–4 mol L–1) for generic, original and standard glyphosate. Calibration curve method was adopted in a comparison. It was observed that there are very minor differences in the slopes of generic, original, and standard glyphosate (0.2982–0.2993–0.2957 μA/μM) respectively.

Author information
  • Analytical and Electrochemistry Research Unit, Chemistry Department, Faculty of Science, Tanta Univeristy, 31111, Tanta, Egypt

    Youssef Ibrahim Moharram & Ibrahim Shibl El-Hallag

  • Microanalysis Laboratory, Kz Corporation for Pesticides and Chemicals, Nubaria, Egypt

    Sameh Mahmoud Selim

References
  1. Stalikas, C.D. and Konidari, C.N., Analytical methods to determine phosphonic and amino acid group-containing pesticides, J. Chromatogr. A, 2001, vol. 907, p. 1.
  2. Börjesson, E. and Torstensson, L., New methods for determination of glyphosate and (aminomethyl) phosphonic acid in water and soil, J. Chromatogr. A, 2000, vol. 886, p. 207.
  3. Kudzin, Z.H., Gralak, D.K., and Drabowiez, J., Novel approach for the simultaneous analysis of glyphosate and its metabolites, J. Chromatogr. A, 2002, vol. 947, p. 129.
  4. Derriche, A.Z., Forano, C., and Prevot, V., Glyphosate and glufosinate detection at electrogenerated NiAl–LDH thin films, Anal. Chim. Acta, 2009, vol. 654, p. 97.
  5. Dos Santos, S.C., Galli, A., and Felsner, M.L., Development of an electroanalytical methodology for determination of pesticide glyphosate in environmental samples, Rev. Virtual Quim., 2014, vol. 6, p. 866.
  6. Teófilo, R.F., Reis, E.L., and Dasilva, G.A., Square wave voltammetry response optimization for the glyphosate determination, J. Braz. Chem. Soc., 2004, vol. 15, p. 865.
  7. Mendez, M.A., Suarez, M.F., and Cortes, M.T., Electrochemical properties and electro-aggregation of silver carbonate sol on polycrystalline platinum electrode and its electrocatalytic activity towards glyphosate oxidation, Electrochem. Commun., 2007, vol. 9, p. 2585.
  8. Gupta, V., Bhavana, K., and Upadhyay, N., Iron(III) selective electrode based on s-methyl n-(methylcarbamoyloxy) thioacetimidate as asensing material, J. Electrochem. Sci., 2011, vol. 6, p. 650.
  9. Long, J.K., Banziger, M., and Smith, M.E., Diallel analysis of grain iron and zinc density in southern African-adapted maize inbreds, Crop Sci., 2004, vol. 44, p. 2019.
  10. Schroeder, J.I., Delhaize, E., and Frommer, W.B., Membrane transporters to improve crops for sustainable food production, Nature, 2013, vol. 497, p. 60.
  11. Sukhmanpreet, K., Vijay, K., and Mohit, C., Pesticides curbing soil fertility: effect of complexation of free metal ions, Front. Chem., 2017, vol. 5, article 43.
  12. Sujittra, P., Chongdee, T., and Panote, T., One-step preparation of porous copper nanowires electrode for highly sensitive and stable amperometric detection of glyphosate, Chem. Pap., 2015, vol. 69, p. 385.
  13. Borman, P. and Elder, D., ICH Quality Guideline: an Implementation Guide, Validation of Analytical Procedures: Text and Methodology Q2 (R1), John Wiley & Sons, 2017, p. 127.
  14. The united states pharmacopeial convention, The united states pharmacopeia; USP 33; NF 28, Rockville, 2010.