High pressure liquid chromatographic determination of nitrofurazone and furazolidone in chicken and pork tissues.

A high pressure liquid chromatographic (HPLC) procedure is presented for the determination of nitrofurazone and furazolidone in chicken and pork tissues in the 2-40 ppb range. Muscle, liver, and kidney are homogenized with cold methanol and water (50 + 50). Following methanol evaporation, the nitrofurans are partitioned into ethyl acetate and cleaned up on an alumina column. After elution with 20% methanol in ethyl acetate and evaporation to dryness, residues are determined by HPLC, using a reverse phase analytical column. Overall average recoveries for nitrofurazone and furazolidone were 65.7 and 73.5%, respectively. Average relative standard deviations of 11.9% (nitrofurazone) and 9.5% (furazolidone) at the 2 ppb level were achieved.

Determination of penicillin G, ampicillin, and cephapirin residues in tissues.

A cylinder plate microbiological method was developed for the rapid, quantitative determination of penicillin G, ampicillin, and cephapirin in animal tissues. The method uses agar plates seeded with stable spores of Bacillus stearothermophilus var. calidolactis and incubated 4 h at 64 degrees C. Standard curves were obtained for the following ranges of concentration of antibiotics in tissues: 0.02-0.32 IU penicillin G/g, 0.0125-0.2 micrograms ampicillin/g, and 0.02-0.32 micrograms cephapirin/g. The proposed method is suitable not only for penicillin residue analysis, for which the sensitivity has been greatly improved compared with the Sarcina lutea method, but also for depletion studies on these antibiotics, which are commonly used to treat diseases in food-producing animals.

Microbiological determination of penicillin G, ampicillin, and cloxacillin residues in milk.

A fast cylinder plate microbiological method was developed for the quantitative determination of penicillin G, ampicillin, and cloxacillin in milk. Agar plates seeded with stable spores of Bacillus stearothermophilus var. calidolactis were used and incubated at 64 degrees C for 4 1/2 hr. Standard curves were obtained for the following ranges of concentration of antibiotics: 0.004-0.064 IU penicillin G/mL, 0.0025-0.04 microgram ampicillin/mL, and 0.03-0.48 microgram cloxacillin/mL. The method is suitable for detecting penicillin residues in milk and for quantitative milk-out studies of the above antibiotics used in treatment of bovine mastitis.

High pressure liquid chromatographic determination of nitrofurazone in milk.

A rapid high pressure liquid chromatographic (HPLC) screening method for the quantitative determination of nitrofurazone in milk has been developed. The drug is extracted with ethyl acetate from a 2.0 ml milk serum sample, the organic layer is evaporated to dryness, and the residue is dissolved in the mobile phase and injected into the liquid chromatogarph. A reverse phase muBondapak C18 column is used with monitoring at 365 nm. The detection limit is 5 ppb and recoveries are 57--67%. Mass spectroscopic confirmation of the HPLC nitrofuran peak is described.

Immunological properties of dialysis retentates from penicillin.

Retentates from benzylpenicillin preparations marketed in Canada were used in immunological studies in order to determine if they were immunogenic in experimental animals with respect to anaphylactic antibody production. The retentates obtained consisted mainly of penicillin polymers. Impurities of protein nature were either insignificant or absent. The penicillin polymers were found to be non-immunogenic in Albino Wistar rats, Wistar Furth rats and Hartley guinea pigs. Furthermore, they were unable to effect positive PCA tests in rats passively sensitized to the penicilloyl determinant.