The quality of EDTA iron products on the market varies greatly. Low-priced inferior products often have problems such as low chelation rate, high impurities and poor effect. Mastering 4 core standards can quickly identify high-quality EDTA chelated iron.

First, check the appearance and water solubility. High-quality EDTA chelated iron is a pale yellow to brownish-yellow uniform powder, no caking and no impurities. Add 1g of sample to 100ml of room temperature clear water, it should dissolve quickly and completely after stirring. The solution is transparent light yellow, no precipitation and no scum, and water insoluble matter should be less than 0.1%. If it dissolves slowly with much residue, it is probably an inferior product mixed with ferrous sulfate.

Second, verify iron content and chelation rate. Regular EDTA chelated iron has a nominal elemental iron content of 13%, and the chelation rate should be ≥98%, meaning most of the iron is chelated and wrapped by EDTA molecules. Some merchants claim that the total iron content meets the standard, but the actual chelation rate is low with much free iron, which is easily fixed by soil after application and greatly reduces the effect.

Third, confirm the pH application range. High-quality EDTA iron is stable and effective between pH 4.0-7.0. You can ask for product stability test reports to check the chelate retention rate at different pH values. If the product claims to be applicable to alkaline soils above pH 8.0, be alert to false publicity.

Fourth, pay attention to impurity indicators. High-quality agricultural grade EDTA iron has low heavy metal content, and arsenic, lead, cadmium and other elements all meet the limit standards of agricultural fertilizers, which will not cause soil pollution. Prioritize factory sources with formal test reports and stable production capacity to ensure product batch stability.