Metamizolesodiumwaschosenasarepresentativeofunstableanalytesforinvestigationbydiscussingtheeffectsofoxygenandsolventonitsdegradationreactionusingthecapillaryelectrophoresistechnique.Apossibledegradationmechanismwasdeducedfromtheobservedbehaviorandwasconfirmedbyinfra-redspectroscopicstudy.Thedegradationreactioncouldbeinhibitedobviouslybymethanolinsteadofwaterasthesolventofanalyte.Undertheoptimizedconditions:separationvoltageof20kV,and5mmol/Ldisodiumhydrogenphosphateand5mmol/Lboraxwith10%methanol(pH9.12)astherunningbuffer,thestandardcurveofmetamizolesodiumwaslinearinarangeof3.77—74.07mg/L.Asatisfactoryresultwasachievedwhenthetechniquewasusedtodetectmetamizolesodiumintablet.
