Carbon film based ring-disk and split-disk dual electrodes as detectors for microbore liquid chromatography
✍ Scribed by Osumu Niwa; Musao Morita; Bruce P. Solomon; Peter T. Kissinger
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 744 KB
- Volume
- 8
- Category
- Article
- ISSN
- 1040-0397
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✦ Synopsis
The electrochemical properties of carbon film based ring-disk and split-disk electrodes in small active volume (0.24-2 pL) radial flow cells were studied in order to employ them in conjunction with microbore liquid chromatography (LC) for determining catechokdmines. The high conversion of dopamine (DA) at the disk of a ring-disk electrode makes the DA limiting current lower than the theoretical value at a low flow rate. The collection efficiency (CE) increases with decreasing flow rate and cell thickness, which is different from previously reported results. A high CE of 0.96 was achieved because of the narrow gap of 5 /Lm.
On the other hand, a higher limiting current was observed with the split-disk than with a coinmercially available dual-disk electrode because of its efficient geometry for analyte collection. The cross talk of the DA after reacting at one of the electrode is only 2%. The ringdisk and split-disk electrodes were suitable as series and parallel electrochemical detectors for small bore LC. A detection limit of 103 fg was obtained for DA at the disk of the ring-disk because of the high signal in the thin-layer radial flow cell and the low noise level of the carbon film. In contrast, very slight interference was observed from neighboring electrodes when determining catecholamines at the split-disk.