Quantitative Determination and Confirmation of Five Synthetic Glucocorticoid Residues in Milk Powder by Gel Permeation Chromatography-Liquid Chromatography-

A new method for multi-residue determination of five synthetic glucocorticoids (betamethasone, dexametha- sone, prednisone, prednisolone, and hydrocortisone) in milk powder is developed. The glucocorticoids in the samples were extracted with tert-butyl methyl ether under ultra- sonication incubation, and then cleaned up through gel permeation chromatography. After C18 LC gradient elution separation using acetonitrile with 0.1% formic acid as a...