Preparation and analysis of cyclotri- and cyclotetraphosphate and their hydrolysis products in soil.

Cyclotriphosphate (Na(3)P(3)O(9)) and cyclotetraphosphate (Na(4)P(4)O(12)) are not strongly sorbed by soil constituents. Potential movement and efficient plant utilization of P from these compounds are dependent on the hydrolysis of the cyclophosphate ring structure and their hydrolysis products. The objectives of this study were to prepare pure useable quantities of these cyclophosphates and their hydrolysis products and to extract, separate, and analyze these compounds after application to diverse soils. Cyclophosphates of high purity (>99.0%) were prepared, and improved methods of extraction and analysis by ion chromatography were developed. Cyclophosphates and their hydrolysis products were extracted from soil using a sequential water/0.5 M H(2)SO(4)/1.0 M NaOH extraction that maximized P recovery and minimized hydrolysis of cyclic and linear phosphates during the extraction procedure. Gradient elution chromatography separated cyclic phosphates and their hydrolysis products. Separation and direct quantitative analysis of the applied cyclophosphates and their hydrolysis products were accomplished in <15 min.