New Derivative UV Spectroscopic Method for Determination of Enrofloxacin in Milk

Milk is considered an essential nutritional source that cannot be dispensed with; therefore, it is crucial to pay special attention to monitoring it, particularly regarding drug residues. This is a new UV spectrophotometric method that is simple, precise, fast, and economical for monitoring the antibiotic Enrofloxacin in milk based on the second-order derivative. Chloroform was used as an extraction solvent, and the drug was determined at a wavelength of 289 nm after centrifugation at 5000 RPM, where milk showed no absorption at this wavelength, unlike the drug. The linearity range was examined and determined to be 0.5–8 μg/mL. The correlation coefficient (R2) was 0.9995. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.03 μg/mL and 0.09 μg/mL respectively. The method shows acceptable linearity, recoveries, accuracy, and precision with percentage relative standard deviation (RSD%) less than 2%. The newly proposed method was validated in accordance with ICH and VICH requirements, and its application on the milk samples was executed.