Chemiluminescence Determination of Cefixime Trihydrate Based on Acidic Diperiodatoargentate(Ⅲ)-Rhodamine 6-G System

A novel chemiluminescence(CL) method is proposed for cefixime trihydrate(CFX) determination based on its eiiliancement effect on diperiodatoargentate(III)(DPA)-rhodamine 6-G(Rh6-G) reaction in conjunction with flow injection analysis(FIA). A linear calibration curve was achieved over the range from 0.01 mg/L to 2.5 mg/L CFX(R^2=0.999,n=8) with relative standard deviation(RSD) of 1.4%-3.8%(n=4)), limit of detection(LOD) of 3.0×10^-3 mg/L(S/N=3),injection tliroughput of 180/h and regression equation of y=1113.2x-14.596[y=CL intensity (mV) and x=concentration of CFX(mg/L)]. The method was successfully applied to CFX determination in pharmaceutical formulations and the recoveries(%) for proposed FI-CL and a reported spectrophotometric method by applying the Student t-test [calculated t-test value: t=1.079215, and tabulated t-distributed(95%)=2.200985] were not significantly diflerent. The CFX was efficiently extracted and no significant effect of commonly found excipients in the pharmaceutical formulations was observed. The mechanism of CL reaction is discussed briefly.