RESUMO
Objective To determine the iodine content of iodine-rich herbal and analyze the effective factors.Methods Iodine contents of seaweed at different alkali ashing temperature,such as 200℃,300℃,400℃,500℃and 600℃were determined,then the optimum ashing temperature were selected.Mixed ashing auxiliary including potassium carbonate,zinc sulfate,sodium chloride,potassium chlorate were added in samples of iodine-rich herbal,and ashed at the optimum ashing temperature for 2h.The ash was dissolved in deionized water.Iodine content of iodine-rich herbal was determined with As3+-Ce4+catalytic spectrophotometry.Results The optimum ashing temperature was 300℃;the standard curve regression equation:A =-6.91 ×10 -3C +1.0306,r =0.999 3;iodine content of seaweed,Kunbu and Haidai was 0.829 mg/g,0.343 mg/g and 0.864 mg/g respectively;recovery rates before ashing of seaweed,Haidai and Kunbu were 83.19%,81.47% and 80.32% respectively;91.24%,93.43% and 95.86% after ashing.Conclusion Iodine is rich in iodine-rich herbal,the optimum ashing temperature is 300 ℃,and As3+ -Ce4+ catalytic spectrophotometry is stable and accurate as a determination method of iodine content of herbal.