title: Mixed micelle-cloud point extraction for the analysis of penicillin residues in bovine milk by high performance liquid chromatography.
abstract: A mixed micelle-cloud point extraction (MM-CPE) has been developed for the analysis of penicillin antibiotics (ampicillin, penicillin G, oxacillin, and cloxacillin) in milk samples using Triton X-114 (TX-114) and cethyl trimethylammonium bromide (CTAB) as the mixed micellar extractant. The parameters affecting the MM-CPE that were investigated including solution pH, CTAB concentration, TX-114 concentration, electrolyte salt, equilibration temperature and incubation time. The optimum MM-CPE conditions were: 10 mmol L(-1) phosphate buffer pH 8, 0.06% (w/v) CTAB, 1.5% (w/v) TX-114, and 7% (w/v) Na(2)SO(4), and 5 min equilibration at 40 degrees C. The separation of penicillins was achieved within 8 min under the HPLC conditions: a Vydac C(18) column, isocratic elution of 5 mmol L(-1) phosphate buffer (pH 6.6) and methanol (55:45, v/v), and a flow rate of 1 mL min(-1), with photodiode array detection at 215 and 244 nm. Under the selected condition, the proposed method gave linear calibrations in the range 0.002-10 microg mL(-1) with correlation coefficients greater than 0.999. Limits of detection (LOD) were 2-3 ng mL(-1), and 15-40-fold enhancement compared to that without preconcentration. Good reproducibility was achieved with relative standard deviation <5% for peak area and <3% for retention time. High accuracy, with recoveries higher than 80%, was obtained. The proposed mixed micelle-CPE-HPLC method has shown to be of high potential for the analysis of penicillin residues in milk with LOD comparable to the established maximum residue limits (4-30 ng mL(-1)).
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: Apichai
authors.initials: A
authors.lastname: Santalad
authors.forename: Suthasinee
authors.initials: S
authors.lastname: Boonchiangma
authors.forename: Rodjana
authors.initials: R
authors.lastname: Burakham
authors.forename: Supalax
authors.initials: S
authors.lastname: Srijaranai
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
mesh_terms: D053000:Analytic Sample Preparation Methods; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D002417:Cattle; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004350:Drug Residues / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D004573:Electrolytes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000737:chemistry; D008823:Micelles; D008892:Milk / Q000737:chemistry*; D017830:Octoxynol; D010406:Penicillins / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D011092:Polyethylene Glycols / Q000737:chemistry; D015203:Reproducibility of Results; D012492:Salts / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D002593:Cetrimonium Compounds; D004573:Electrolytes; D007202:Indicators and Reagents; D008823:Micelles; D010406:Penicillins; D012492:Salts; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40; D000077286:Cetrimonium