Ascorbic acid as a reductant for extraction of iron-bound phosphorus in soil samples: a method comparison study.

Sequential extraction is commonly used to identify and quantify different forms of phosphorus (P) associated with particulate samples. Iron (Fe)-bound P is an important fraction of total particulate phosphorus because iron (Fe) is ubiquitous in natural environments. Three reductant solutions, i.e., sodium hydroxide (NaOH), dithionite, and ascorbic acid, have been used to extract solid phase reactive iron and associated phosphorus from sediments and soils. This study compares the efficiencies of three different methods in extracting Fe and Fe-bound P and evaluates the potential and limitation of each method. Based on the results of this comparative study it is recommended that the ascorbic acid reduction method is used for extraction of Fe-bound P in particulate samples, such as soil and sediment. [ABSTRACT FROM AUTHOR]