A precise and simplified method of sample preparation for the simultaneous quantification of the antibiotics β-lactam, macrolide, tetracycline, sulfonamide, and quinolone in bovine milk was developed. The central composite design of response surface methodology was used to design and optimize the method for the determination of six different antibiotic residues in milk. The recovery of each antibiotic was studied using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Octadecylsilane (C18), primary secondary amine (PSA), and sodium acetate (Na acetate) were the main factors affecting the recovery of each antibiotic. After optimization, the maximum predicted recovery rate was 84.18% for erythromycin under the optimized conditions of 101.20 mg C18, 52.00 mg PSA, and 1.01 g Na acetate. The recovery rates of the five other antibiotic residues ranged from 86.09% to 115.99%. The results suggested that modified QuEChERS could effectively be implemented in the analysis of antibiotic residues in milk.
