But corrosion products have great influence to the determination, a pretreatment is conducted on sample with aluminium hydroxid suspension,and error is less in sample testing after the treatment.

• 而腐蚀产物对测定产生较大干扰，可用氢氧化铝悬浮液进行样品的预处理，处理后的样品测定结果偏差较小。