1. © ADSORPTIVE DIFFERENTIAL-PULSE STRIPPING VOLTAMMETRY OF NORFLOXACIN AND ITS ANALYTICAL APPLICATION JABER, AMY; LOUNICI, A ROYAL SOC CHEMISTRY, ANALYST; pp: 2351-2357; Vol: 119 King Fahd University of Petroleum & Minerals http://www.kfupm.edu.sa Summary Cyclic voltammetric investigations have been performed which showed that norfloxacin exhibits adsorptive processes at the hanging mercury drop electrode (HMDE) in various base electrolytes of pH < 9 such as LiCl, NaCl-NaOH (pH 8.8), CH3CO2Na, CH3CO2Na-CH3CO2H (pH 7.5) and NH3-NH4Cl (pH 8). Adsorptive preconcentration followed by differential-pulse cathodic stripping in various base electrolytes showed voltammograms of three waves in the ranges of -1.02 to -1.18, - 1.28 to -1.34 and -1.43 to -1.54 V with the one at -1.02 V being the most sensitive wave in most cases. The optimum experimental parameters were assessed for each base electrolyte. In general, accumulation potential, E(acc), scan rate, v, and accumulation time, t(acc), were found to be in the ranges of 0 to 0.1 V, 2 to 10 mV s(- 1) and 60 to 300 s, respectively. The calibration plots showed more than one linear segment in the same base electrolyte. These segments covered ultratrace levels of norfloxacin extended from 0.32 to 900 ng l(-1) (1.0 x 10(-12) to 3.0 x 10(-9) mol l(- 1)) and from 0.32 to 65 mu g l(-1) (1.0 x 10(-9) to 2.0 x 10(-7) mol l(-1)) depending on the base electrolyte and the adsorptive peak used for analysis. These linearities may be ascribed to pure adsorptive and mixed adsorptive-diffusion processes. Ten successive adsorptive stripping peak measurements yielded relative standard deviations, s(r), of 2.5 to 6.0% for various norfloxacin concentrations in the range of 4.82 to 39.6 mu g l(-1) in different base electrolytes. Norfloxacin in Noroxin commercial tablets was determined using the standard addition technique for concentrations at ng l(-1) and mu g l(-1) levels. Good recoveries were obtained Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa

2. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. © without an interference of the drug excipients. References: BARD AJ, 1980, ELECTROCHEMICAL METH, P525 CAI QT, 1993, ANAL CHIM ACTA, V276, P99 CROHER K, 1992, CHEM BR, V28, P34 EMONS H, 1990, CONT ELECTROANALYTIC, P407 JABER AMY, 1994, ANAL CHIM ACTA, V291, P53 KALVODA R, 1982, ANAL CHIM ACTA, V138, P11 KALVODA R, 1989, PURE APPL CHEM, V61, P97 KALVODA R, 1990, CONT ELECTROANALYTIC, P403 LAVIRON E, 1974, J ELECTROANAL CHEM, V52, P395 LAVIRON E, 1975, J ELECTROANAL CHEM, V63, P245 LAVIRON E, 1979, J ELECTROANAL CHEM, V100, P263 LEJEUNE R, 1992, ANAL CHIM ACTA, V256, P59 ODEA P, 1991, ELECTROANAL, V3, P337 SMITH JT, 1984, PHARM J, V233, P299 TAMER A, 1990, ANAL CHIM ACTA, V231, P129 TELTINGDIAZ M, 1990, ANALYST, V115, P1215 VILLAR JCC, 1993, TALANTA, V40, P325 WANG J, 1992, ANALYST, V117, P1913 WANG J, 1992, TALANTA, V39, P1273 WANG J, 1992, TALANTA, V39, P801 For pre-prints please write to: abstracts@kfupm.edu.sa Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa