15 © The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com Journal of Chromatographic Science, 2021, Vol. 59, No. 1, 15–22 doi: 10.1093/chromsci/bmaa069 Advance Access Publication Date: 20 October 2020 Article Article Sensitive and Fast Determination of Ceftiofur in Honey and Veterinary Formulation by HPLC-UV Method with Pre-column Derivatization Noha Rashed 1 , Sahar Zayed 2,3, * , Fatma Fouad 1 , and Amany Abdelazeem 1 1 Analytical Chemistry Department, Faculty of Pharmacy (Girls), Al-Azhar University, El Nasr St., Cairo 11754, Egypt, 2 Unit of Drug Analysis, Faculty of Pharmacy, University of Mansoura, 25 El Gomhouria St., Mansoura 35516, Egypt, and 3 Pharmacy Department, Emergency Hospital, University of Mansoura, 25 El Gomhouria St., Mansoura 35516, Egypt *Author to whom correspondence should be addressed. Email: s1zayed@yahoo.com Received 15 July 2019; Editorial Decision 28 August 2020 Abstract A novel, sensitive and rapid high performance liquid chromatography (HPLC) method for the determination of ceftiofur by pre-column derivatization with 1,2-naphthoquinone-4-sulfonate. Analysis was performed within 5 min on a Kinetex C18 column based on core-shell technology. The mobile phase composed of acetonitrile-water (50:50, v/v) pumped isocratically at a flow rate of 1.0 mL/min under UV detection at 254 nm. The factors affecting the derivatization reaction and separation conditions were carefully evaluated and optimized. The method was linear over the concentration range of 45–450 ng/mL with a limit of detection of 3.29 ng/mL and limit of quantitation of 10.97 ng/mL. The new method was successfully applied for the analysis of ceftiofur in the veterinary formulation and honey with average recoveries of 100.78% and 98. 83%, respectively. The present method is suitable and favorable for the analysis of ceftiofur on account of its sensitivity, rapidity and cost-effectiveness. In addition, it could have significant application for the determination of ceftiofur in other food products. Introduction Ceftiofur (CEFT) is a third-generation cephalosporin antibiotic used in veterinary medicine (1). It has worldwide approvals for respiratory disease as it control bacterial infections of the respiratory tract in animals, poultry, milk cows and bees (2). The use of antibiotic drugs in apiculture is restricted, however, beekeepers are commonly using antibiotics to fight or prevent bacterial or other bee diseases (3). This is presenting a risk to human health including allergies even at very low doses in some subjects or producing resistant strains among human pathogens (4). There are currently no European Union antibiotic Maximum Residue Limits (MRLs) set in honey. A technical guide was published by the European Union Reference Laboratories (EU-RL) in 2007 [4]. The objective of this technical guide is to improve the performance of analytical methods for substances for which MRLs have not been set. Therefore, accurate, sensitive and simple analytical methods are required for the determination of such antibiotics in honey. Several methods have been reported for the determination of CEFT including: square wave voltammetry (5, 6), spectrophotometry (7–9), HPLC-UV (10), HPLC-PDA (11, 12), HPLC-MS (13, 14), HPLC-MS/MS (15), UPLC-MS (16, 17) and capillary electrophoresis (CE) (18). Among these methods, each exhibits disadvantages that limit its application, such as poor sensitivity for UV detection at low analyte concentrations, colorimetric methods are less accurate and less specific than HPLC. In addition, expensive equipment for MS detection or CE are still prohibitive for an average laboratory. 1,2-naphthoquinone-4-sulfonate (NQS) is a reagent able to react with both primary and secondary amino groups to produce spec- trophotometrically detectable derivatives. The advantages of NQS over other derivatization reagents are its free water solubility, strong Downloaded from https://academic.oup.com/chromsci/article/59/1/15/5930845 by guest on 06 February 2022