Phosphate fertilizers are popular due to their relatively high nutrient content. Due to rapid developments in the modern fertilizer industry, especially with the formulation of compound/complex fertilizers, many phosphate fertilizers may have multiple phosphorus-containing components.
The co-existence of these various phosphorus sources in a compound/complex fertilizer can complicate the effective extraction and determination of the phosphorus content.
ISO 22018 specifies the method for the determination of the EDTA soluble phosphorus content of inorganic fertilizers. The method is applicable for fertilizers composed of or blended from multiple sources such as superphosphate, ammonium phosphate, triple superphosphate, and/or nitrophosphate.
Note: The method is not suitable for fertilizers containing calcium magnesium phosphates.
ISO 22018 on EDTA in fertilizer is useful for:
Owing to the variation of basic phosphate component, character, and processing technology, traditionally, different extraction solutions and methods have been utilized for the determination of the phosphorus content of phosphate fertilizers. Extraction solutions currently employed for phosphorus content determination include alkaline ammonium citrate, neutral ammonium citrate, citric acid, and EDTA. Each of these extractants is designed to target specific phosphate components of phosphorus-based fertilizers.
ISO 22018 walks you through a method for determining the EDTA soluble phosphorus content of inorganic fertilizers. The test procedure described in ISO 22018 includes guidelines for the preparation of the test sample, the extraction of EDTA soluble phosphorous, and the determination of the EDTA soluble phosphorous content. ISO 22018 also guides you through the calculation and expression of results including repeatability and reproducibility. Using ISO 22018 guidelines you would be able to determine the EDTA soluble phosphorus content in fertilizers.
BS ISO 22018:2021 has re-dated normative references with respect to ISO 22018.
ISO 22018