A method for the extraction of monoester phosphorus components in lake sediments and the analysis of phosphorus NMR spectra

Abstract

The invention belongs to the technical field of environmental chemical analysis and testing methods and particularly relates to a method for extraction of monoester-P components in lake sediment and P nuclear magnetic resonance spectroscopy analysis. The method comprises 1, pretreating lake sediment through a Na2S solution and extracting concentrate to obtain a solution 1 to be detected, 2, carrying out 31P-NMR spectroscopy analysis on the solution 1 to be detected, and calculating the content of monoester-P through a ratio of the peak area of monoester-P to the total area and content of total P in the extract. The method obviously improves an extraction rate of monoester-P. The extraction rate of monoester-P in lake sediment is 1-2 times that of the traditional one-step long-term extraction method. The method can precisely analyze 11 monoester-P components and their corresponding contents. Compared with the traditional analysis method, the method improves an accuracy rate by 3-10%.

Description

technical field [0001] The invention belongs to the technical field of environmental chemical analysis and testing methods, and in particular relates to a method for extracting monoester phosphorus components in lake sediments and analyzing phosphorus nuclear magnetic resonance spectra. Background technique [0002] Phosphorus is one of the key limiting nutrient elements in aquatic ecosystems. Excessive phosphorus leads to the growth and reproduction of algae, causing deterioration of water quality and endangering the safety of ecosystems. In recent years, the input of exogenous phosphorus, including domestic sewage, industrial and agricultural production, and soil runoff, has been controlled to a certain extent, and the release of endogenous phosphorus in lakes has become a key factor causing further deterioration of lake water quality. Sediment release is one of the important sources of endogenous phosphorus pollution in lakes, and organic phosphorus is an important compon...

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Problems solved by technology

However, practice has proved that these analysis methods have the following problems: (1) comparison found that taking the chemical shift of orthophosphate as a reference, different literature reports 31 The chemical shifts of phosphorus compounds in the P-NMR spectrum are different

Especially monoester phosphorus, because the chemical shift is concentrated and close to each other, with the chemical shift of orthophosphate as a reference, different analytical results will be obtained with reference to the chemical shift reported in different documents; (2) directly add phosphorus standard substance in the extract, In order not to affect the identification of monoester phosphorus, standard substances far away from the chemical shift region of monoester phosphorus are often used, such as MDPA, whose chemical shift is between 17-18ppm, far away from the region of monoester phosphorus, as a standard, refer to literature reports, can not accurately judge 31 The monoester phosphorus compound corresponding to the corresponding chemical shift in the P-NMR spectrum; (3) The ion concentration of the extract in the sediment will affect the chemical shift of the phosphorus compound. Synchronously with the sediment extraction, set a standard sample with organic phosphorus The simulated standard sample obtained from the background solution has a large difference in ion concentration and organic matter from the sediment extract solution. Practice has proved that the chemical shifts of the two are very different, especially in the monoester phosphorus region.

[0009] In addition, there are various types of lakes, and the geological background of lakes in different regions is very different, as well as the basic properties of sediments such as mineral composition, which lead to large differences in background values ​​such as ionic strength and organic matter content in the organic phosphorus extraction solution of sediments, which directly lead to in different sediment extracts 31 P-NMR spectrum chemical shift difference

Therefore, there is still no reliable method to obtain the lake sediment extract in the above traditional analysis methods. 31 Accurate Analysis Results of Monoester Phosphorus Components in P-NMR Spectrum

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