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Mediated Oxidation and Determination of Gaseous Monomethyl Hydrazine in a Solid‐State Voltammetric Cell Employing a Sol‐Gel Electrolyte
Author(s) -
Holmstrom Scott D.,
Sandlin Zechariah D.,
Steinecker William H.,
Cox James A.
Publication year - 2000
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/(sici)1521-4109(20000301)12:4<262::aid-elan262>3.0.co;2-f
Subject(s) - amperometry , detection limit , electrolyte , working electrode , cyclic voltammetry , electrode , electrolytic cell , electrochemistry , supporting electrolyte , overlayer , chemistry , oxide , inorganic chemistry , hydrazine (antidepressant) , materials science , analytical chemistry (journal) , chromatography , electrolysis , metallurgy
Mesoporous silica that was prepared by a sol‐gel process was used as the electrolyte for the amperometric determination of vapor‐phase monomethyl hydrazine (MMH). Three detection strategies were tested, namely cyclic voltammetry at a Pt working electrode with the oxidation mediated by Fe II,III that was hosted by the silica, pulsed electrochemical detection with a gold working electrode, and potentiostatic oxidation at a mixed‐valence ruthenium oxide (mvRuOx) film that was deposited on a Pt working electrode prior to casting the solid electrolyte overlayer. The sensitivities (and linear dynamic ranges) for the respective methods were 1.4 nA/ppm (500–1400 ppm), 0.49 nA/ppm (70–1050 ppm), and 0.30 nA/ppm (1–1050 ppm). With pulsed electrochemical detection and mvRuOx, respective detection limits of 20 ppm and 0.3 ppm were calculated on the basis of a concentration that yielded a response three times the standard deviation of the blank. Because of high uncertainty of the intercept of the Fe II,III ‐mediated method, a detection limit was not calculated for this technique. A cell design that provided a three‐phase boundary at a mvRuOx‐modified electrode yielded a response of 90 % of the steady‐state current at 11 s.