PARALLEL INCIDENT SPECTROELECTROCHEMISTRY STUDY OF CHLORAMPHENICOL

The electrochemical behavior of chloramphenicol (CAP) at a graphite el ectrode has been investigated by parallel incident spectroelectrochemi stry (PISEC) accompanied by cyclic voltammetry. The redox electrode re action mechanism of CAP under different pH conditions has been describ ed. In NH4Cl-NH4OH buffer solution (pH 8.0), CAP undergoes an irrevers ible 4-electron reduction at negative potential to give NHOH-CAP. Cons equently, a new redox-active species is formed at more positive potent ials, which has been identified as the NHOH-CAP/NO-CAP couple. In 0.1 mol/l HCl media, CAP undergoes an irreversible B-electron transfer, co rresponding to reduction of the nitro group to amine. The content of C AP in eyedrops has been determined by PISEC in ammonia buffer solution (pH 8.0) under the initial reduction of CAP. The linear range of quan titation was 1.0 x 10(-6) mol/l similar to 2.5 x 10(-4) mol/l, with a correlation coefficient of 0.999. The determination recoveries were 95 .5%similar to 101.5%. (C) 1998 Elsevier Science B.V.