... content determination method: UV1, reagent and instrument improved amino benzaldehyde methanol HP8453 uv-vis spectrophotometer 1 cm than color dish 2 ... product solution take 200 mg in 10 ml RongLiangPing, add methanol, ultrasonic oscillations 30 min, cold to room temperature to scale ... absorb the filtrate 2 ml in 10 ml RongLiangPing, plus methanol 3 ml, improved amino benzaldehyde 5 ml, densely plug, ...