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Screen‐printed voltammetric sensors for 2‐furaldehyde based on nickel‐modified and amalgam‐stabilized mercury‐coated carbon inks
Author(s) -
Slater Jonathan M.,
Dilleen John W.
Publication year - 1997
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140091710
Subject(s) - mercury (programming language) , nickel , detection limit , chemistry , electrochemistry , furan , cyclic voltammetry , electrode , inorganic chemistry , analytical chemistry (journal) , chromatography , organic chemistry , computer science , programming language
Abstract This article describes a general method for stabilizing microdroplets of mercury on thick‐film screen printed electrodes (SPEs). Electrodes modified with nickel metal powder are compared with amalgam stabilized mercury SPEs. Application of the electrodes to the measurement of organic materials is demonstrated by the electrochemical determination of 2‐furaldehyde, a marker for power transformer condition monitoring. The electrodes were characterized by cyclic voltammetry and subsequently a square‐wave voltammetric method was used to extend the detection limit of the measurement. The resulting cathodic currents for the reduction of 2‐furaldehyde was proportional to the concentration of 2‐furaldehyde. Plots of 2‐furaldehyde concentration against response at a nickel‐modified carbon SPE gave linear regions for concentrations in the range 3.7–14.3 ppm (regression equation; Y = 0.99 + 0.15 x,r = 0.999, n = 3), and linear regions at mercury‐coated silver‐modified carbon SPEs in the range 8.9–36.4 ppm (regression equation; Y = 1.71 + 0.14 x,r = 0.999, n = 3) and in the range 0.9–8.9 ppm (regression equation; Y = 1.34 + 0.17 x,r = 0.980, n = 3), respectively. A particular advantage of using the mercury‐modified SPE rather than the nickel‐modified base card is that the well‐defined electrochemistry of furan derivatives allow them to be individually distinguished. The half‐wave potentials at the mercury SPE for 2‐furaldehyde ( E 1/2 = −1.15 V vs. Ag/AgCl) and two possible interferents 2‐acetyl‐furan and 5‐methyl‐2‐furaldehyde ( E 1/2 = −1.2 and −1.31 V vs. Ag/AgCl) are sufficiently well separated to allow the individual components to be resolved whereas at a nickel‐modified SPE a combined signal is observed.