磷酸盐饲料及其原料中磷和钙的快速测定

磷的测定是从含磷和钙的稀HNO(?)溶液中,用已知过量的铋盐沉淀磷酸根;分出一份滤液,以二甲酚橙为指示剂,用EDTA滴定余下的铋.钙的测定则另取一份滤液,加三乙醇胺掩蔽铋,加NaOH使滤液为碱性,以钙指示剂确定终点,仍用EDTA滴定.笔者研究了测定磷的准确度同沉淀磷酸铋时的酸度和P(?)O_5含量之间的关系,以及氯离子对测定的干扰及消除方法.并用拟定的方法分析了某些样品,结果令人满意.与标准方法相比,节约了一半以上的药品和分析时间.

Rapid Determination of Phosphorus and Calcium in Fodder Phosphate and Phosphate Raw Materials

Phosphorus was determined by precipitation from dilute HNO,solution with a knownamount Bi, and titration undonsumed Bi3 with EDTA ( xylenol orange as indicator) . In a separateportion, after the precipitation step, free Bi3 was masked with triethanolamine, the solution was made alkaline with NaOH, and Ca2 was titrated with EDTA (Calcon-carboxylic acid as indicator) . We have studied the relations between the accuracy of determining phophorus and acidity of precipitation, amounts of P2O5, and influences of Cl-. Some samples have been analysed by this method with satisfactory results. Comparing with standard method, it may economizes more than one half in time and reagents.