Flow electrochemical determination of ascorbic acid in real samples using a glassy carbon electrode modified with a cellulose acetate film bearing 2,6-dichlorophenolindophenol

Abstract An ascorbate sensor based on a glassy carbon electrode modified with a cellulose acetate polymeric film bearing 2,6-dichlorophenolindophenol (CA/DCPI-CME) was constructed. The overall reaction obeys a catalytic regeneration mechanism (EC mechanism) and the electrochemical rate constant kf for the electrocatalytic oxidation of ascorbic acid was evaluated. The modified electrodes were mounted in a flow injection (FI) manifold, poised at +100 mV versus Ag/AgCl/3 M KCl at pH 6.5 and utilized for the determination of ascorbic acid in beverages and pharmaceuticals. Good correlation with a reference method was attained. Interferents of various molecular sizes were tested. Calibration graphs were linear over the range 0.02–1 and 0.1–6 mM ascorbic acid for CA/DCPI sensors hydrolyzed in KOH and ZnCl2 solution, respectively. The throughput was 25 samples per hour and the CV was for a 0.4 mM ascorbic acid solution 0.75 (n=14) and 1.2% (n=10) for CA/DCPI sensors hydrolyzed in KOH and ZnCl2 solution, respectively. The recovery was 92–110%. The sensors showed very good repeatability and operational stability.

[1]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[2]  M. Karayannis.  Comparative kinetic study for rate constant determination of the reaction of ascorbic acid with 2,6-dichlorophenolindophenol. , 1976, Talanta.

[3]  Brian J. Birch,et al.  Development of screen-printed carbon electrodes, chemically modified with cobalt phthalocyanine, for electrochemical sensor applications , 1990 .

[4]  S. Rowe,et al.  Food Science , 1962, Nature.

[5]  H. Abruña,et al.  Aldehyde Biosensor Based on the Determination of NADH Enzymically Generated by Aldehyde Dehydrogenase , 1995 .

[6]  R. Murray,et al.  Electrocatalysis with ferrocyanide electrostatically trapped in an alkylaminesiloxane polymer film on a Pt electrode , 1982 .

[7]  J. Wang,et al.  Selectivity and sensitivity improvements at perfluorinated ionomer/cellulose acetate bilayer electrodes. , 1986, Analytical chemistry.

[8]  G. Verreschi,et al.  Use of surfactant-modified cellulose acetate for a high-linearity and pH-resistant glucose electrode , 1996 .

[9]  J. Savéant,et al.  Heterogeneous (chemically modified electrodes, polymer electrodes) vs. homogeneous catalysis of electrochemical reactions , 1978 .

[10]  Eric P. Achterberg,et al.  Laboratory techniques in electroanalytical chemistry , 1996 .

[11]  Juozas Kulys,et al.  Printed electrochemical sensor for ascorbic acid determination , 1991 .

[12]  J. Kulys,et al.  Electrocatalytic oxidation of ascorbic acid at chemically modified electrodes , 1991 .

[13]  Bing Chen,et al.  Determination of copper by zeolite molecular sieve modified electrode , 1997 .

[14]  P. Cunniff.  Official Methods of Analysis of AOAC International , 2019 .

[15]  M. Petersson.  Electrocatalytic oxidation of ascorbic acid and voltammetric determination with a ferrocene-modified platinum electrode , 1986 .

[16]  T. Golden,et al.  Cobalt phthalocyanine/cellulose acetate chemically modified electrodes for electrochemical detection in flowing streams. Multifunctional operation based upon the coupling of electrocatalysis and permselectivity. , 1988, Analytical chemistry.

[17]  W. Horwitz.  Official Methods of Analysis , 1980 .

[18]  M. Karayannis,et al.  Electrocatalytic Oxidation of NADH in Flow Analysis by Graphite Electrode Modified with 2,6‐Dichlorophenolindophenol Salts , 1998 .

[19]  C. N. Reilley,et al.  Analysis of electrochemical mechanisms by finite difference simulation and simplex fitting of double potential step current, charge, and absorbance responses , 1978 .