Comparative Evaluation of Electron Paramagnetic Resonance and Spectrophotometry for DPPH-Based Antioxidant Capacity Determination

Description

Helvis L. S. Fontoura and six colleagues compare two instruments for the DPPH test, a workhorse assay that rates how well substances neutralize free radicals. Labs usually read the test by light absorption, while a magnetic method called EPR watches the radicals directly. Measuring the same samples both ways at once, the team found the light method systematically underrates scavenging power. Leftover color from spent reagent and breakdown products fools the light reading.

Three correction procedures were designed and shown to erase the statistical gap between the two methods. The fixes held for standard phenolic compounds and for deeply pigmented samples, including a purple fruit juice rich in anthocyanins. Pigment still disturbs very concentrated readings, yet the key potency values come out right after correction. The authors offer the corrections as a path to standardizing a test that food and natural product labs run every day.

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Source: https://europepmc.org/article/MED/PMC13647961