Preparing comparable color references for ferric ammonium citrate grades

Set up the comparison

Prepare colour samples under one light source with the same concentration, vessel and background. Record the stated grade and the basis of the iron assay.

Measurements to record

Elemental iron (% as received). Identify the brown or green grade and measure actual iron content rather than estimating from the chemical name. Appearance and color (Color difference or visual assessment). Fix light source, specimen thickness and concentration. Compare retained samples after storage where appropriate. Record the sample ID and method revision for repeat testing.

Interpreting the results

Assess iron content and solution colour independently. Check moisture and storage history against the approved reference before accepting a different colour grade.

What to record

• Grade
• Iron reporting basis
• Solution concentration
• Light source
• Finished-product colour

Technical references

• ENVO: Ferric Ammonium Citrate product information ↗

Products and processes