Potentiometric and Optical Measurements for the Determination of Ephedrine

✍ Scribed by M.M. Zareh; R. El-Shiekh; R. El-Bahnasawy; D.O. Abo-El-Naga

• Book ID: 102614384
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 117 KB
• Volume: 60
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1998.1646

✦ Synopsis

A PVC membrane electrode based on the ephedrine reineckate ion pair was constructed. Small ion pair percentages (0.1-5% w/w) were tested successfully giving Nernstian behavior. The slope of the calibration graph was 56 mV/decade for the 5% ion pair. The optimum working pH range of the electrode is 4.0 -9.0. The linear usable concentration range is 2 ϫ 10 Ϫ6 to 10 Ϫ1 M ephedrine. The suitable selectivity of the electrode toward ephedrine relative to other cations, amines, sugars, and some pharmaceuticals was recorded. The potential drift of the electrode did not exceed 0.58 mV/day. The effect of temperature on electrode performance was studied in the range of 25-95°C and it worked with Nernstian behavior up to 85°C. Electrode performance is compared with that of previously reported electrodes. The determination of ephedrine in its pharmaceutical preparations was performed with a mean recovery of 98.7% and average relative standard deviation of 1.9%. Application of the membrane to optical measurements for ephedrine was attempted at different pH values.