Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Japan.
Research Institute for Humanity and Nature, Kyoto, Japan.
Rapid Commun Mass Spectrom. 2022 Nov 30;36(22):e9384. doi: 10.1002/rcm.9384.
Phosphate (PO ) oxygen isotope (δ O ) analysis is increasingly applied to elucidate phosphorus cycling. Due to its usefulness, analytical methods continue to be developed and improved to increase processing efficiency and applicability to various sample types. A new pretreatment procedure to obtain clean Ag PO using solid-phase extraction (SPE) with zirconium-loaded resin (ZrME), which can selectively adsorb PO , is presented and evaluated here.
Our method comprises (1) PO concentration, (2) PO separation by SPE, (3) cation removal, (4) Cl removal, and (5) formation of Ag PO . The method was tested by comparing the resulting δ O of KH PO reagent, soil extracts (NaHCO , NaOH, and HCl), freshwater, and seawater with data obtained using a conventional pretreatment method.
PO recovery of our method ranged from 79.2% to 97.8% for KH PO , soil extracts, and freshwater. Although the recovery rate indicated incomplete desorption of PO from the ZrME columns, our method produced high-purity Ag PO and accurate δ O values (i.e., consistent with those obtained using conventional pretreatment methods). However, for seawater, the PO recovery was low (1.1%), probably due to the high concentrations of F and SO which interfere with PO adsorption on the columns. Experiments indicate that the ZrME columns could be regenerated and used repeatedly at least three times.
We demonstrated the utility of ZrME for purification of PO from freshwater and soil extracts for δ O analysis. Multiple samples could be processed in three days using this method, increasing sample throughput and potentially facilitating more widespread use of δ O analysis to deepen our understanding of phosphorus cycling in natural environments.
磷酸盐（PO ）氧同位素（δ O ）分析越来越多地用于阐明磷循环。由于其有用性，分析方法不断得到开发和改进，以提高处理效率和适用于各种样品类型。本文介绍并评估了一种新的预处理程序，使用负载锆的树脂（ZrME）固相萃取（SPE）获得纯净的 Ag PO ，该方法可以选择性地吸附 PO 。
我们的方法包括（1）PO 浓度，（2）SPE 分离 PO ，（3）阳离子去除，（4）Cl 去除，（5）Ag PO 的形成。通过比较 KH PO 试剂、土壤提取物（NaHCO 、NaOH 和 HCl）、淡水和海水的 δ O 值与使用常规预处理方法获得的数据，测试了该方法的效果。
对于 KH PO 、土壤提取物和淡水，我们的方法的 PO 回收率范围为 79.2%至 97.8%。虽然我们的方法表明 PO 从 ZrME 柱上不完全解吸，但它产生了高纯度的 Ag PO 和准确的 δ O 值（即与使用常规预处理方法获得的值一致）。然而，对于海水，PO 回收率较低（1.1%），可能是由于高浓度的 F 和 SO 干扰了柱上的 PO 吸附。实验表明，ZrME 柱至少可以再生和重复使用三次。
我们证明了 ZrME 用于从淡水和土壤提取物中纯化 PO 进行 δ O 分析的实用性。使用该方法可以在三天内处理多个样品，提高样品通量，并有可能促进 δ O 分析的更广泛应用，以加深我们对自然环境中磷循环的理解。
