What are the specific colorimetric quantitative tests for estimation galactaric acid?

Specific colorimetric quantitative tests for estimating galactaric acid often involve the use of reagents such as 3,5-dinitrosalicylic acid (DNSA) or anthrone, which react with galactaric acid to produce a colored complex. The intensity of the color formed is measured spectrophotometrically at a specific wavelength, allowing for the quantification of galactaric acid concentration through comparison with standard curves. Other methods may include the use of phenol-sulfuric acid or orcinol reagents, which also yield measurable color changes in the presence of galactaric acid.