In this paper, anthocyanins and chlorophyll were extracted from purple cabbage, purple potato, eggplant peel, spinach, coriander, mint, broccoli and water spinach by ethanol extraction. According to the correlation be...In this paper, anthocyanins and chlorophyll were extracted from purple cabbage, purple potato, eggplant peel, spinach, coriander, mint, broccoli and water spinach by ethanol extraction. According to the correlation between transmittance and absorbance, the research method of discoloration range and discoloration point of natural acid-base indicator is established by using the light module of smart phone "phyphox". The results showed that the color of anthocyanins and chlorophyll in the acidic range was obviously changed. The color of anthocyanins was pink pH3.0~4.5, purple pH4.6~5.3, blue pH5.4~6.7, green pH6.8~8.0, yellow pH3.0~3.8, yellow and green pH3.9~5.4 and green pH5.5~8.0in the acidic range, respectively. It can be used as a natural acid-base indicator for titration reaction in the acidic range.展开更多
文摘In this paper, anthocyanins and chlorophyll were extracted from purple cabbage, purple potato, eggplant peel, spinach, coriander, mint, broccoli and water spinach by ethanol extraction. According to the correlation between transmittance and absorbance, the research method of discoloration range and discoloration point of natural acid-base indicator is established by using the light module of smart phone "phyphox". The results showed that the color of anthocyanins and chlorophyll in the acidic range was obviously changed. The color of anthocyanins was pink pH3.0~4.5, purple pH4.6~5.3, blue pH5.4~6.7, green pH6.8~8.0, yellow pH3.0~3.8, yellow and green pH3.9~5.4 and green pH5.5~8.0in the acidic range, respectively. It can be used as a natural acid-base indicator for titration reaction in the acidic range.
