Publications by authors named "Righter H"

Two complementary methods for identifying and measuring sulfonamide residues in eggs were developed for use in surveying eggs for potential drug residues. The first method uses liquid chromatography-tandem mass spectrometry (LC-MS-MS) to confirm the presence of sulfonamide residues in eggs. During its validation the limit of confirmation was estimated to be 5-10 ng/g (ppb) depending on the drug.

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A new procedure for the confirmation of two aminoglycoside antibiotics in milk was developed and validated. This work is among the early applications of ion trap mass spectrometry for regulatory methodology, and it incorporates a novel weak cation-exchange extraction. The procedure was validated for the confirmation of both gentamicin and neomycin at 30 ng ml(-1) and above.

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A gas chromatographic method for determination of 2-hydroxymethyl-1-methyl-5-nitroimidazole (DMZOH), the hydroxy metabolite of dimetridazole, in swime muscle has been developed. The method uses cleanup steps similar to those of an earlier polarographic method. The present method is capable of quantitating levels as low as 2 ppb and detecting less than 1 ppb.

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Sulfadimethoxine was administered (IV) to suckling pigs (1 to 2 weeks old) and to growing pigs (11 to 12 weeks old) at a dosage of 55 mg/kg of body weight (single dose). Blood samples were collected over a 48-hour period, and the animals euthanatized were used for measurements of plasma and tissue concentrations of the drug. The blood data were described, using a one-compartment pharmacokinetic model.

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Four lactating Holstein cows were each given a single oral dose of either 0.5 g 2,5,2',5'-tetrachlorobiphenyl, 0.5 g 2,5,2',4',5'-pentachlorobiphenyl, 1.

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