Supercritical Fluid Extraction Compared with Solvent Method for Incurred Sulfamethazine in Chicken Eggs

ABSTRACT To obtain eggs containing “normally incurred” sulfamethazine (SMZ), 10 hens were fed a single dose of 75 mg/kg SMZ by capsule. The amount of SMZ in some of the eggs (n = 21) was determined by two extraction methods, supercritical fluid extraction (SFE) and solvent extraction. The mean SMZ values ranged from 0.10 to 0.78 ppm, with an overall mean of 0.32 ppm and no difference (p>0.05) was found between the methods. However, SFE provided a distinct advantage over other methods since the amount of sample manipulation and solvent use and disposal was minimal. Determination of SMZ in the normally incurred eggs over an 8‐day period by SFE showed that levels reached a maximum after the first day, then declined slowly. However, SMZ exceeding 0.10 ppm still occurred 5 days after dosing.