摘要
十六烷基三甲基溴化铵（cetyltrimethylammonium bromide, CTAB）可与磷钼蓝（phosphomolybdenum blue, PMB）生成水难溶的PMB-CTAB离子缔合物沉淀，从而分离富集水溶液中的PMB。该沉淀易溶于硫酸乙醇溶液，溶液在700nm有强吸收，基于此建立了沉淀分离富集-分光光度法测定海水中痕量活性磷酸盐的新方法。对溶剂酸度、试剂用量、反应时间与温度等实验参数进行了优化选择，并考察了盐度对测定结果的影响。实验结果表明，PMB可被CTAB有效地定量沉淀；盐度在15～45范围内，对测定结果无影响。在优化的实验条件下，以盐度为35的人工海水为基底，做空白加P标实验，方法的线性范围为0．30～8．00μg／L，平均回收率为95．0％，方法检测限为0．10μg／L。对实际海水中痕量活性磷酸盐进行测定，相对标准偏差（RSD）为4．4％～7．1％，与广泛采用的MAGIC法比较，置信度为99％时结果无显著差异。新方法具有消耗试样体积少、测定速度快等优点。
An ion pair compound of phosphomolybdenum blue （PM B） with cetyltrimethylammonium bromide （CTAB） precipitated from aqueous solution can be easily dissolved in sulfuric acid enthanol solution. Based on this, a novel method was established to determine the trace orthophosphates in seawater. The experimental parameters, including acid concentration in the solvent, the reagent concentrations, the reaction time and temperature, were optimized. The effect of salinity was also studied. The results showed that PMB could be efficiently precipitated by CTAB, and the precipitation was not influenced by the salinity within 15 and 45. Under the optimized conditions, using artificial seawater （35） as a matrix, the linearity, the recovery and the detection limit of the proposed method were 0.30 to 8.00 μg/L, 95.0% and 0.10 μg/L, respectively. The RSDs ranged from 4.4 to 7.1% for the real seawater samples. Two seawater samples were analyzed with both the proposed method and magnesium hydroxide-induced coprecipitation （MAGIC） method. The results showed no significant difference with t test and confidence interval 99%. The proposed method has the advantages to be fast detection and little sample.
出处
《海洋环境科学》
CAS
CSCD
北大核心
2006年第3期81-85,共5页
Marine Environmental Science
基金
国家自然科学基金(20277030)
关键词
沉淀富集
磷钼蓝
活性磷酸盐
十六烷基三甲基溴化铵
precipitation preconcentration
phosphomolybdenum blue
orthophosphates
cetyltrimethylammonium bromide
