Optimization of Determination Conditions of Sulfur Dioxide Residue in Chilli Products by Automatic Potentiometric Titration

A method using automatic distillation apparatus coupled with automatic potentiometric titration was established to determine SO₂ residue in chili products. The optimal conditions were determined by orthogonal test L₁₆(4⁵),and the results were as follows:The distillation time 5 min,the volume of distilled water 200 mL,the volume of received solution 40 mL,the stirring speed 8 r/min,the potential change rate 50 mV/min. On this condition,the relative standard deviations were between 0.69%~0.95%,the standard addition recoveries were between 98.3%~99.6%. This method is simple,rapid and accurate. It’s suitable for the automated testing of large quantities of sample. The results can provide reference for study SO₂ residue in chili products and other food.