基于液相31P核磁共振技术的河流沉积物有机磷提取剂选择研究

以高磷污染河流沉积物为研究对象,利用液相31P核磁共振(31P-NMR)技术研究了沉积物中有机磷提取剂的选择和提取过程.结果表明:前提取以BD和EDTA效果最佳,TP和Po的提取量分别为(322.87±13.81)和(119.76±16.00)mg·kg-1、(24.91±15.25)和(20.90±2.58)mg·kg-1,2种提取剂均促进了NaOH的提取效率,前提取后NaOH提取液中TP和Po的提取量分别达到(2271.20±75.63)和(2477.40±112.71)mg·kg-1、(152.04±1.55)和(186.93±20.53)mg·kg-1;对顺磁性离子Fe和Mn而言,利用BD和EDTA+Na2S2O4作为前提取剂可以提取更多的Fe离子,提取液中的浓度分别为(5116.57±24.32)和(10677±215.61)mg·kg-1;EDTA和EDTA+Na2S2O4提取剂对Mn的去除效量较高,提取液中浓度分别为(243.02±2.80)和(266.61±1.61)mg·kg-1.液相31P-NMR图谱显示,上述提取剂处理后均可得到正磷酸盐、焦磷酸、磷酸单酯、磷脂和DNA 5种磷形态,其中EDTA可提高沉积物中正磷酸盐、焦磷酸盐、磷脂和DNA的含量.综合考虑:利用EDTA和NaOH两步提取可实现较高的Po提取量和较低的顺磁性离子干扰,并得到理想的核磁共振图谱,从而保证沉积物中有机磷液相31P-NMR分析的科学性和有效性.

Characterization and optimization of the extractants for solution 31P-nuclear magnetic resonance (31P-NMR) analysis of organic phosphorus in river sediments

A two-step extraction using different extractants was studied on the phosphorus (P) pollution river sediments by solution ³¹P-NMR. Pro-extraction using BD or EDTA all increased TP and Po extraction amounts in NaOH post-extraction, which were (2271.20±75.63) and (2477.40±112.71) mg·kg^-1 for TP, and (152.04±1.55) and (186.93±20.53) mg·kg^-1 for Po. Moreover, the extractants (BD or EDTA+Na₂S₂O₄) increased Fe extraction amounts in pro-extraction, reaching (5116.57±24.32) and (10677±215.61) mg·kg^-1, respectively, while EDTA or EDTA+Na₂S₂O₄ increased Mn extraction amounts in pro-extraction, reaching (243.02±2.80) and (266.61±1.61) mg·kg^-1, respectively. Five P species, including orthophosphate (ortho-P), pyrophosphate (pyro-P), orthophosphate monoesters (mono-P), phospholipids (lipids-P) and deoxyribonucleic acids (DNA-P), were all detected in different extractions, and the EDTA pro-extraction could increase the concentrations of ortho-P, pyro-P, lipids-P and DNA-P. The results showed that the two-step extraction using EDTA and NaOH could increase TP and Po extraction amounts in post-extract and Fe and Mn extraction amounts in pro-extract, which optimized ³¹P-NMR spectroscopy for Po analysis.