氧瓶燃烧苏木精为指示剂测定棉籽中的总磷

Oxygen-flask Combustion Method of Determination of the Total Phosphorus in Cotton Seed Using Haematoxylin as Indicator

氧瓶燃烧法以硝酸镧标准溶液做滴定剂，苏木精为指示剂，测定棉籽中的总磷。该方法不受硫的干扰，相对标准偏差为０．３％～５．７％，检知量为０．０４９ｍｇ，回收率为９９．５７％～１０３．４２％，适合于一般实验室测定有机磷样品。

The oxygen-flask cormbustion method is used to determine the total phosphorus in cotton seed using lanthanum nitrate as titrant and haematoxylin as indicator. It is not interfered by sulphur. The relative standard deviation is 0. 3%￣5. 7%, the detection limit is 0. 049mg, th.e recovery is 99. 57%￣103. 42%. This mathod can be applied to the determination of organic. phosphorus samples in common laboratory.