~(31)P-NMR分析湖泊植物和藻类有机磷方法优化及形态研究

应用不同的提取剂和固液比提取湖泊水生植物和藻类中的藻类有机磷(P_0),并进一步采用液态核磁共振(~(31)P-NMR)技术分析其组成特征.结果表明:采用0.5mol/L NaOH+25mmol/LEDTA提取剂,并控制固液比为1:60可获得最优的P_0提取效果;~(31)P-NMR分析测试过程中,设置延迟时间(D1)为5s,扫描分析时间为15h(约扫描24000次)可获得较好的谱图.通过以上实验方法,分析水生植物和藻类中磷均由正磷酸盐、单酯磷、二酯磷及焦磷酸盐组成,其中P_0可分别占总磷(TP)的34-21%~53.36%和31.27%~72.96%.单酯磷是水生植物和藻类P_0的主要组分,其平均含量可占P_0的92%和83%;二酯磷含量均较少,占TP的0~6.65%;藻类体内焦磷酸盐含量可达水生植物的35倍.

Optimization of extraction and parameters for31P-NMR analysis of organic phosphorus extracted from aquatic plants and algae

Characterization of organic phosphorus (P_o) from aquatic plants and algae by solution 31P-Nuclear Magnetic Resonance (³¹P-NMR) is important to understand its biogeochemical cycling in lakes. Methods of extraction and selection of parameters for NMR characterization and quantification of P_o critical. Various extractants and radio of sample to extractants were applied for ³¹P-NMR. A mixture of 0.5mol/L NaOH-25m mol/L EDTA with a ratio of sample to extractant of 1:60 was the optimal extraction of P_o from aquatic plants and algae. When the extract was analyzed by use of ³¹P-NMR, the delay time (D1) and scanning time were set to 5s and 15h, respectively, which resulted in approximately 24,000 scans. Based on how Samples were extracted and results of ³¹P-NMR analysis, P in aquatic plants and algae included orthophosphates, orthophosphate monoesters, orthophosphate diesters and pyrophosphate, of which P_o accounted for 34%~53% and 31%~73% respectively. Orthophosphate monoester was the predominant constituent of P_o, which accounted for 92 and 83% of plants and algae, respectively. The proportion of orthophosphate diesters was small in aquatic plants and algae and accounted for only 0~6.65% of the TP. The content of pyrophosphate in algae was approximately 35-fold greater than that in aquatic plants.