Study on Rapid Pretreatment Method with Cobalt (III) Ions for Speciation of phosphorus in Environmental Samples

研究了钴（III）氧化有机磷的前处理方法，通过电解硫酸钴（II）的酸性溶液产生钴（III）离子，用于光度法测定环境水样中的磷。该预处理方法首先以间歇方式进行检测，然后应用于流动注射分析系统中的在线预处理。钴（III）预处理使得<-3>具有C-O-P或C-P键的有机磷化合物的mg dm ↑ [2]水平的磷在室温下借助于铂催化剂在7分钟内完全转化为磷酸根离子;来自试剂的钴（III）离子不干扰随后通过钼蓝法测定磷酸根离子。在预处理过程中，缩合磷酸盐需要在95-100 ℃下加热才能完全水解。磷的检测限为0.005 mg dm ↑ <-3>[3]，每小时可测定10-12个样品（FIA系统）。除还原性物质含量较高外，本方法不受有机物和无机物共存的干扰，适用于真实的水样中有机磷和总磷的测定。

A pretreatment method of organic phosphorus based on cobalt (III) oxidation, was studied for spectrophotometric determination of phosphorus in environmental water samples ; cobalt (III) ions were produced through the electrolysis of an acidic solution of cobalt (II) sulfate. The pretreatment first examined in a batchwise mode and then applied to an on-line pretreatment in a system of flow injection analysis (FIA). The cobalt (III) pretreatment enabled complete conversion of mg dm^<-3> level of phosphorus of organic phosphorus compounds having C-O-P or C-P bond into phosphate ions within 7 min at room temperature with an aid of a platinum catalyst ; cobalt (III) ions from the reagent did not interfere with the subsequent determination of phosphate ions by the Molybdenum Blue method. Condensed phosphates required heating at 95-100ﾟC for complete hydrolysis during the pretreatment. The detection limit for phosphorus was 0.005 mg dm^<-3> and 10-12 samples could be determined per 1h (the FIA system). Since the present method was free from any interference from coexisting organic and inorganic substances, except at a relatively high level of reducing substances, it is applicable to the determination of organic or total phosphorus in real water samples.