A study of the differential pulse polarographic and stripping voltammetric behavior of the H+/K+ ATPase inhibitor SK&F 95601 and its degradation products
✍ Scribed by S. McClean; T. Maxwell; V. N. Ramachandran; E. O'Kane; W. F. Smyth
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 758 KB
- Volume
- 6
- Category
- Article
- ISSN
- 1040-0397
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✦ Synopsis
The differential pulse polarographic (DPP) behavior of SK&F 95601 (I) has been studied in the pH range 0 to 14. At pH I 2 , (I) rapidly degrades into the sulfenamide (D:) and sulfide (DS), which are both reduced by 2e-processes, the former being subject to strong reactant adsorption. SK&F 95601 itself is reduced in a 4e process up to pH10, and either pK2 or pK, values, determined spectrophotometrically, are manifested polarographically at neutral pH A pK, value of 9.0 corresponding to the benzimidazole N-H group deprotonation is manifested polarographicallp with a pK5 value of ca. 11. SK&F 95601 and its degradation products D;, degraded D:, and DS can all be determined by adsorptive stripping voltammetry (AdSV) with limit of detections (LODs) of lo-' mol dm-3, except for the latter molecule with an LOD of lo--mol dm-3. These LODs are superior to those determined by DPP. Mixtures of these molecules can also be resolved with similar LODs. Cd" can be determined by ASV with a superior LOD in the presence of (I), i.e., 0.08 ppb as compared to 0.57 ppb in its absence, due to chelation phenomena.