Abstract: A method was established for the determination of sulfite content in toothpaste by ion chromatography.With formaldehyde solution as stabilizing agent of SO^2-₃,samples were extracted with 10 mmol·L^-1 sodium hydroxide solution and were separated on a Metrosep Supp 5-250 chromatographic column using solution of V(3.2 mmol·L^-1 Na₂CO₃+1.0 mmol·L^-1 NaHCO₃):V(acetone)=88:12 as the eluent.The flow rate was 0.5 mL·min^-1 and the injection volume was 20 μL.With this method,range with good linearity for sulfite was 0.10~10 mg·L^-1 with the correlation coefficient of 0.999 9.The recoveries,relative standard deviations and detection limits were 84.7%-90.1%,1.06%-3.18% and 5 mg·kg^-1 respectively.

Key words: toothpaste, ion chromatography, sulfite