title: High performance liquid chromatography for the simultaneous analysis of penicillin residues in beef and milk using ion-paired extraction and binary water-acetonitrile mixture.
abstract: An ion-paired extraction (IPE) has been developed for the analysis of penicillin antibiotics (penicillin G, oxacillin and cloxacillin) in beef and milk samples using tetrabutylammonium bromide (TBABr) as ion-pairing agent and binary water-acetonitrile as extractant. The factors affecting the IPE efficiency were optimized including solution pH, volume of acetonitrile (ACN), concentration of TBABr and electrolyte salt (NH(4))(2)SO(4). The optimum IPE conditions were 10 mmol L(-1) phosphate buffer pH 8, 2 mL of ACN, 6 mmol L(-1) of TBABr and 2.5 mL of saturated ammonium sulfate. Under the HPLC condition: an Xbridge™ C18 reversed-phase column, isocratic elution of 5 mmol L(-1) phosphate buffer (pH 6.6) and acetonitrile (75:25, v/v) and a flow rate of 1 mL min(-1), with UV detection at 215 nm, the separation of three penicillins was achieved within 10 min. Under the selected optimum conditions, the enhancement of 21-53 folds compared to that without preconcentration and limits of detection (LODs) of 1-2 ng mL(-1) were obtained. Good reproducibility was achieved with RSD<2% for retention time and <5% for slope of calibration curves. The average recoveries higher than 85% were obtained. The proposed IPE-HPLC method has shown to be high efficient preconcentration and analysis method for penicillin residues in beef and milk with LOD lower than the maximum residue limits.
authors.affiliation: Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Chunyapuk
authors.initials: C
authors.lastname: Kukusamude
authors.forename: Rodjana
authors.initials: R
authors.lastname: Burakham
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
authors.forename: Supalax
authors.initials: S
authors.lastname: Srijaranai
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000645:Ammonium Sulfate / Q000737:chemistry; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003023:Cloxacillin / Q000032:analysis*; D004350:Drug Residues / Q000032:analysis*; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D059625:Liquid-Liquid Extraction; D008460:Meat / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D010068:Oxacillin / Q000032:analysis*; D010400:Penicillin G / Q000032:analysis*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000644:Quaternary Ammonium Compounds; D014867:Water; C009405:tetrabutylammonium; D003023:Cloxacillin; D010400:Penicillin G; D000645:Ammonium Sulfate; D010068:Oxacillin; C032159:acetonitrile