A novel analytical method namely magnetic solid phase extraction in tandem with dispersive liquid-liquid microextraction was developed and used for the extraction/preconcentration of tetracycline (TCN), oxytetracycline (OTC) and doxycycline (DC) from bovine milk sample before HPLC-UV analysis. The β-cyclodextrin functionalized silica-coated magnetic graphene oxide (Fe₃O₄@SiO₂@GO-β-CD) was used as an adsorbent. The adsorbent was fully characterized using FT-IR, SEM, EDX and Zeta potential techniques. The effective parameters on the performance of the method such as extraction solvent type and volume, adsorbent amount, desorption solvent type and volume, disperser solvent type, desorption time, ionic strength and pH value were investigated. The limit of detection (LOD) and limit of quantification (LOQ) were obtained in the ranges of 1.8–2.9 μg L⁻¹ and 6.1–9.7 μg L⁻¹, respectively. The linearity was in the range of 10.0–200.0 μg L⁻¹ with satisfactory determination coefficients (R²) higher than 0.9929 and a good precision (RSD < 8.8%). The recovery percentages for the analytes in real samples (bovine milk and water) were achieved in a range from 70.6 to 121.5%.

开发了一种新颖的分析方法，即磁性固相萃取与分散液-液微萃取串联，用于从牛奶样品中进行HPLC-UV分析之前的四环素（TCN），土霉素（OTC）和强力霉素（DC）的萃取/预富集。 。β-环糊精官能化的二氧化硅包覆的磁性氧化石墨烯（Fe ₃ O ₄ @SiO ₂将@GO-β-CD）用作吸附剂。使用FT-IR，SEM，EDX和Zeta电位技术对吸附剂进行了全面表征。研究了该方法性能的有效参数，如萃取溶剂的类型和体积，吸附剂的量，解吸溶剂的类型和体积，分散剂的类型，解吸时间，离子强度和pH值。在1.8-2.9微克L上的范围，获得的检测限（LOD）和定量限（LOQ）的限制^-1和6.1-9.7微克大号^-1分别。线性在10.0–200.0μgL ^-1的范围内，具有令人满意的测定系数（R ²）高于0.9929，并且具有良好的精度（RSD <8.8％）。实际样品（牛乳和水）中分析物的回收率达到70.6％至121.5％。