Fig. 4From: Smart stability indicating spectrophotometric methods for determination of modafinil: the promising treatment for post-covid neurological syndromeFirst derivative of ratio spectra of 5-30 µg/mL modafinil (–) and 50 µg/mL of degradation product (—) using 70 µg/mL of degradation as a divisor at (241.8 nm) in methanolBack to article page