ABSTRACT
A rapid, specific, and sensitive method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM) was developed and validated to quantify flumethasone residues in beef muscle. Methods were compared between the original as well as the EN quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction. Good linearity was achieved at concentration levels of 5-30 µg/kg. Estimated recovery rates at spiking levels of 5 and 10 µg/kg ranged from 72.1 to 84.6%, with relative standard deviations (RSDs)<7%. The results of the inter-day study, which was performed by fortifying beef muscle samples (n=18) on 3 separate days, showed an accuracy of 93.4-94.4%. The precision (expressed as relative standard deviation values) for the inter-day variation at two levels of fortification (10 and 20 µg/kg) was 1.9-5.2%. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.7 and 5 µg/kg, at signal-to-noise ratios (S/Ns) of 3 and 10, respectively. The method was successfully applied to analyze real samples obtained from large markets throughout the Korean Peninsula. The method proved to be sensitive and reliable and, thus, rendered an appropriate means for residue analysis studies.
Subject(s)
Drug Residues/analysis , Flumethasone/analysis , Food Contamination , Food Inspection/methods , Glucocorticoids/analysis , Meat/analysis , Muscle, Skeletal/chemistry , Animals , Calibration , Cattle , Chromatography, High Pressure Liquid , Cost Savings , Drug Residues/isolation & purification , Flumethasone/isolation & purification , Food Inspection/economics , Glucocorticoids/isolation & purification , Limit of Detection , Meat/economics , Reproducibility of Results , Republic of Korea , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry , Time Factors , Tissue Extracts/chemistry , Tissue Extracts/isolation & purificationABSTRACT
A capillary electrophoresis technique was developed for the separation of synthetic glucocorticoids and the determination of dexamethasone and flumethasone in horse urine. Pretreatment of the sample using a dexamethasone affinity column resulted in low background that enabled the authors to detect levels as low as 1.1 ng/mL and 2.7 ng/mL for dexamethasone and flumethasone in horse urine, respectively. The developed method was used to detect dexamethasone in horse urine samples after the injection of a therapeutic dose of dexamethasone for up to 12 hr postinjection. The optimum conditions for capillary electrophoresis and dexamethasone elution from the affinity column are described.
