title: Development of a method for the determination of pyrimethamine concentrations in feeds by ion-pairing high-performance liquid chromatography.
abstract: An ion-pairing reversed-phase high-performance liquid chromatography (HPLC) method with diode array detection at 280 nm was developed to determine pyrimethamine concentrations in feed for laying hens. Pyrimethamine was extracted with a mixture of 5% isobutanol and 95% benzene, and the extract was cleaned up on an alumina column. The drug was eluted from an Intersil ODS-3V column (250 by 4.6 mm) with a mixture of 25% acetonitrile and 75% water (vol/vol) containing 0.01 M tetramethylammonium chloride as an ion-pairing agent and adjusted with acetic acid to pH 3.5. The flow rate was 1.0 ml/min. Mean recovery of pyrimethamine from supplemented feeds at concentrations of 2, 4, and 5 microg/g of feed were 100.5, 103.5, and 100.8%, respectively. Precision within a day ranged from 4.3 to 7.0% for the three concentrations, and day-to-day precision was 5.3% for feed supplemented at a concentration of 4 microg/g. No chromatographic interference was detected from other 2,4-diaminopyrimidine compounds or other major drugs used in poultry.
authors.affiliation: Branch Institute of Animal Drugs Inspection, National Institute for Animal Health, Miaoli, Taiwan, Republic of China.
authors.forename: P S
authors.initials: PS
authors.lastname: Gong
authors.forename: S L
authors.initials: SL
authors.lastname: Jeng
authors.forename: Y F
authors.initials: YF
authors.lastname: Hsu
authors.forename: C C
authors.initials: CC
authors.lastname: Lin
authors.forename: S Y
authors.initials: SY
authors.lastname: Lin
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D000981:Antiprotozoal Agents / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D011739:Pyrimethamine / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000981:Antiprotozoal Agents; D011739:Pyrimethamine