Alizarin complexone is obtained by the condensation of alizarin with formaldehyde solution and iminodiacetic acid in the presence of alkaline conditions.

茜素络合指在碱性条件下由茜素、甲醛和亚氨二乙酸缩合而成。

So the mixed indicator of phenolphthalein with alizarin red-methyl red could be used as the new indicator for the alkalify water determination.

采用百里蓝-甲、甲绿-甲混和指的测试效果较差。