Operation of Amperometric Electrodes

Modem amperometric detectors possess a number of useful features. These include rapid response time, low cell volume, ease of access to the electrode surface for cleaning, ability to be used in series with other detectors, good sensitivity with suitable analytes, in-built facilities for scanning the detection potential and minimal mnning costs. Since amperometric electrodes are small it is possible to incorporate more than one into a thin-layer electrode block. Most commercial cells usually contain two electrodes with their necessary connections. At the simplest level this allows the rapid connection of the second electrode when the first becomes contaminated. The electrode connections are simply transferred to the other electrode pin without having to dismantle the cell. A discussion of the use of two or more amperometric electrodes for differential analysis is given below (Section 7). 

Use of serial GCEs [electrode 1 (A) —0.8 V, (B) 0 V electrode 2 (A) and (B) +0.85 V V5 Ag/AgCl] to facilitate the ED of fluphenazine sulfoxide. Column 300x3.9 (i.d.) mm x Bondpak ODS-silica 10 m. Eluent methanol-formic acid (0.15 mol containing dibutylamine (10 mmol L j, pH3.2 (50 + 50) Flow-rate 2.0 mL min Injection lyophilised 3-methyl-1-butanol (isopenta-nol) extract of plasma containing added fluphenazine, fluphenazine sulfoxide and other fluphenazine metabolites (amounts and injection volume not given) Peaks 1 = fluphenazine sulfoxide, 2 = 7-hydroxyfluphenazine, 3 = 8-hydroxyfluphenazine, 4 = fluphenazine, 5 = fluphenazine N-oxide. 

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