A New First-Derivative Photochemically-Induced Fluorescence Spectrometric Method for the Determination of Sulfapyridine in Milk

A new first-derivative photochemically-induced fluorescence (D-PF) method is proposed for the determination of sulfapyridine (SPY) in milk. An 60:40 v/v ethanol-water medium and a 8-min UV irradiation time were selected for D-PF measurements. The method is suitable for SPY concentrations ranging from 0.1 to 0.6 ppm. Limits of detection are comprised between 6 and 21 ppb. Recoveries between 95 and 102% are found. This new D-PF method is remarkably simple, rapid, precise, and it allows one to determine low levels of SPY in milk without prior separation.