A semi-automated method for the determination of inorganic, organic and total phosphate in sediments

TLDR

The study presents a simple, rapid, semi‑automated method to quantify inorganic, organic, and total phosphorus in lake and river sediments. The method extracts total phosphorus from sediments using 1 N HCl after ignition at 550 °C or by sulfuric acid‑potassium persulphate digestion at 135 °C in a sealed PTFE‑lined Parr bomb, determines organic phosphorus by the difference before and after ignition, and measures orthophosphate with standard Technicon AutoAnalyzer II techniques. The method shows no interference from silica or varying acid concentrations, and delivers accurate, precise recoveries, confirming its suitability for monitoring inorganic, organic, and total phosphorus in sediments.

Abstract

A simple, rapid and semi-automated method for the determination of inorganic, organic and total phosphorus in lake and river sediments is described. Total phosphorus is extracted from sediments with 1 N hydrochloric acid after ignition at a high temperature (550 °C) or by digestion with sulphuric acid-potassium persulphate at 135 °C in a sealed PTFE-lined Parr bomb. Organic phosphorus is determined by the difference in phosphorus content of the 1 N hydrochloric acid extract measured before and after ignition of the dry sediments at 550 °C. In all instances the orthophosphate is determined by using standard Technicon AutoAnalyzer II techniques. The interferences caused by silica and variable acid concentrations on the determination of phosphorus have been studied. Freedom from interferences under the chosen experimental conditions as well as the good results obtained for recovery and precision indicate that the methods are suitable for monitoring inorganic, organic and total phosphorus in sediments.