Nisbeth Catharina S, Tamburini Federica, Kidmose Jacob, Jessen Søren, O'Connell David W
Department of Geosciences and Natural Resource Management (IGN), University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.
Institute of Agricultural Sciences, ETH Zurich, 8315 Lindau, Switzerland.
MethodsX. 2022 Apr 16;9:101706. doi: 10.1016/j.mex.2022.101706. eCollection 2022.
The ability to identify the origin of phosphorus and understand processes controlling P cycling is essential for designing effective mitigation and restoration of eutrophic freshwater ecosystems. The oxygen isotope composition of orthophosphate (δO) has significant potential as a tracer for P entering freshwater ecosystems. However, methods of analysis of δO are still in their preliminary stages and have proven challenging to implement for new practitioners. In order to achieve progress in developing the application of δO signatures as a tracing tool, there is a need to eliminate the methodological challenges involved in accurately determining δO. This protocol article describes the various steps needed to concentrate and isolate orthophosphate in freshwater samples into an adequately pure AgPO analyte, without isotopic alteration during processing. The protocol compiles the disperse experiences from previous studies, combined with our own experience. The twofold aim of the paper is toprovide a baseline for an increasing standardisation of the silver phosphate purification method associated with analysis of the oxygen isotope composition of orthophosphate (δO), and to foster new research in the applicability of δO signatures for P source tracing in catchment science.
识别磷的来源并了解控制磷循环的过程的能力对于设计富营养化淡水生态系统的有效缓解和恢复措施至关重要。正磷酸盐的氧同位素组成（δO）作为进入淡水生态系统的磷的示踪剂具有巨大潜力。然而，δO的分析方法仍处于初步阶段，事实证明对新从业者来说实施起来具有挑战性。为了在将δO特征作为一种追踪工具的应用开发方面取得进展，有必要消除准确测定δO所涉及的方法学挑战。本文描述了将淡水样品中的正磷酸盐浓缩并分离成足够纯净的AgPO分析物所需的各个步骤，且在处理过程中不会发生同位素改变。该方案汇集了先前研究的分散经验，并结合了我们自己的经验。本文的双重目的是为与正磷酸盐氧同位素组成（δO）分析相关的磷酸银纯化方法日益标准化提供一个基线，并促进δO特征在流域科学中磷源追踪适用性方面的新研究。
