磷钼蓝分光光度法测试聚羧酸减水剂中的磷酸根含量

Phosphor molybdenum blue spectrophotometric determination of phosphate in polycarboxylate superplasticizer

采用磷钼蓝分光光度法测试聚羧酸减水剂样品中的磷酸根含量,考察了检测波长、酸度、显色时间、钼酸铵、亚硫酸钠、对苯二酚及抗坏血酸对实验结果的影响。结果表明,最佳试验条件为:检测波长为650 nm,显色时间为30 min,在10 g经处理的聚羧酸减水剂样品中加入硫酸(1+1)、钼酸铵、亚硫酸钠、对苯二酚及抗坏血酸的体积分别为0.75、2.0、2.5、2.5、1.0 m L。在此实验条件下,测试吸光度与质量浓度具有较好的线性关系,方法回收率为100.82%~102.05%,相对标准偏差为0.62%,该方法操作简单,测试结果精度高、准确度好,可用于减水剂样品生产的质量控制。

Molybdenum blue spectrophotometric method was used for the determination of phosphate in polycarboxylate superplasticizer.Some crucial determination parameters,including detection wavelength,acidity,color development time,amount of ammonium molybdate,sodium sulfite,hydroquinone and aseorbic acid were investigated.Results showed that the optimal values of the above parameters were as follows：detection wavelength 650 nm, color development time 30 min,the volume of sulfuric acid （1＋ 1）,ammonium molybdate,sodium sulfite,hydroquinone and ascorbic acid added in 10 g of the treated polyearboxylate superplasticizer were 0.75,2.0,2.5,2.5, 1.0 mL. Under these conditions,a good linear relationship between absotbance and phosphate concentration was observed. Mean recoveries of phosphate from 100.82% to 102.05%,with a mean RSD of 0.62%. The method has simple operation,high precision and accuracy,and therefore is applicable to the quality control in polycarboxylate superplasticizer production.