灰化法磷测定中不同灰化助剂的效果比较——以磷酸氢二钠作为磷标样

对Na 2HPO4加入不同灰化助剂经不同温度（150～550℃）灼烧后磷的回收率进行了研究。所研究的灰化助剂除文献中已深入研究过的MgSO4和Mg(No3)2外，还对MgCl2等十余种盐剂进行了实验。作者认为，在利用目前已被广泛应用的由Solбrzano和Sharp 1980年所提出的方法去分析海水中的颗粒磷和总磷或有机体中的磷时，应当用MgCl2或Mg(Ac）2作为灰化助剂而取代MgSO4。尽管Mg(NO3)2也是高效的灰化辅助剂，但其应用的危险性及更多的手工操作可能限制了其广泛应用。     

海水中磷氮不同形态的同时测定

采用过硫酸钾-硼酸-氢氧化钠混合试剂作为氧化剂,同时测定海水中总磷、氮和总溶解态磷、氮,从而建立了海水中磷、氮不同形态的分析流程及步骤。总磷、总溶解态磷浓度为0.35～1.09μmol/dm3时,相对标准偏差小于6.6%;总氮、总溶解态氮浓度为11.8～54.8μmol/dm3时,相对标准偏差小于5.6%。总磷、总溶解态磷和总氮、总溶解态氮的回收率分别为95.0%～106.0%和94.0%～106.0%。本文的分析方法可用于对近岸海水及河口水中磷、氮不同形态的同时测定。     

Continuous flow analysis of dissolved total phosphorus in seawater by UV-K2S2O8 online digestion method

Several methods for analysis of dissolved total phosphorus in seawater were reviewed. Discussions were focused on UV irradiation and persulphate oxidation methods which are the most popular dissolved organic phosphorus determination methods presently. The compounds used for the phosphorus recovery test were categorized into three groups according to their chemical structure. It was found that low power UV irradiation can decompose P-O-C or P-C bonds efficiently but may be inefficient for P-O-P bonds. Heating-bath in acid condition is useful for decomposing P-O-P bonds. Using the continuous flow analysis system (Auto-analyzer Ⅱ), UV digestion and heating-bath, series experiments were carried out based on the above analysis. Eleven model compounds were employed for the phosphorus recovery test and the factors influencing the decomposition efficiency of dissolved compounds containing phosphorus were clarified. Finally, the optimal design for determination of dissolved total phosphorus in seawater based on the routine continuous flow analysis system was presented. For the organic mono-phosphate, the recovery is more than 90% and a recovery of 33%～51% was obtained for inorganic or organic polyphosphates. Up to now, this is the highest decomposition efficiency for dissolved phosphorus based on the continuous flow analysis system.