Voltammetric electrodes modified with swollen polyacrylic latex particles

Abstract

a b s t r a c tUniformly sized poly(N-isopropylacrylamide-co-acrylic acid) (NIPA/AA) hydrogel particles were synthesized in order to modify an electrode with a carboxyl group-immobilized one-particle layer. They were spheres with a common diameter under given conditions, which ranged from 0.5 lm to 1.0 lm depending on the pH, ionic concentration and temperature. They were swollen at low salt concentrations, low temperatures and high pH of aqueous suspensions. One particle contained 6.0 Â 10 8 carboxyl groups, the concentration of which was ca. 1 M, exhibiting pK a = 5.2. The particles were adsorbed spontaneously on the platinum surface in a one-particle layer with regular arrangement. The particle-adsorbed electrode showed the voltammetric peak for the reduction of hydrogen ions which were dissociated from the carboxylic groups of the adsorbed layer. The amount of the dissociated hydrogen ions per particle was 19% of the loaded amount of carboxyl groups, whereas the non-gelized particles had 3% of the loaded amount. The film worked as a source of supply of hydrogen ions for the electrochemical reduction of 1,4-naphthoquinone. It provided acidic environment of pH 4.5 for the reduction in the neutral solution.

Au nanoparticles/poly(caffeic acid) composite modified glassy carbon electrode for voltammetric determination of acetaminophen

“…6B. The slopes are close to the theoretical value of 59 mV/pH demonstrating that the electrochemical reaction of AP is a two-proton coupled two-electron transfer [25][26][27][28]. Thus, the electrocatalytic AP oxidation scheme at AuNPs/PCA-GC electrode is as shown in Scheme 1.…”

Power law for frequency-dependence of double layer capacitance of graphene flakes

“…Density of the dried GN, q, was determined by means of pycnometry, which was used for evaluating the density of swollen polyacrylic latex particles [42]. The method was to obtain weights of a ca 50 cm 3 dried pycnometer (m 0 ) and that (m w ) of the pycnometer into which water was filled.…”

Voltammetric Determination of the Adsorption Kinetics of Acetic Acid on Activated Carbon

“…Considering that strong acids are fully dissociated in diluted aqueous solutions, the reduction process is attributed to the reduction of H + . 18 In HAc solution, the cathodic peak was observed at −0.53 V at the same condition. Thus, the reduction reaction is related to the dissociation of HAc.…”

“…11 The voltammetric behaviors of various acids at platinum microelectrodes under steady state conditions have been extensively investigated in the past two decades. [12][13][14][15][16][17][18][19][20] Strong acid, which is completely dissociated, has been found to prove a well-defined, transport-controlled wave. Reduction current is proportional to acid concentration over a wide range as well as to hydrogen ion transport rate.…”