máy đo PH kỹ thuật số ph Máy đo độ PH SmartSensor AS218 0. 00 14.00pH Dụng cụ đo độ ẩm nước Máy đo độ axit PH

 the preparation of the buffer solution1. PH4 buffer solution with accessories distribution of  powder in 250 ml distilled water, fully dissolved  dilution 30 minutes.2. PH6.86 buffer solution with accessories distribution  of powder in 250 ml distilled water, fully dissolved  dilution 30 minutes.3. PH9.18 buffer solution with accessories distribution  of powder in 250 ml distilled water, fully dissolved  dilution 30 minutes.