Chloramphenicol extraction from milk by using the diphasic dialysis method followed by liquid chromatographic determination

An economical, fast, and simple method for the extraction and liquid chromatographic determination of chloramphenicol (CAP) in milk is described. CAP is extracted by using a recently developed membrane-based method named "diphasic dialysis." CAP is detected and quantitated in the organic solvent used in dialysis without additional cleanup steps by reversed-phase liquid chromatography and UV detection (270 nm). The determination limit of CAP in milk was about 5 micrograms/L, although as little as 1 microgram/L could be detected under optimal working conditions.

Phenotypic and phylogenetic evidence for a close relationship between Lactococcus garvieae and Enterococcus seriolicida

Cultural, biochemical and protein profiling studies were performed on L. garvieae strains isolated from diseased rainbow trout and on the fish pathogen Enterococcus seriolicida ATCC 49156. The results, confirmed by 16 rRNA sequence analyses, indicate that E. seriolicida ATCC 49156 should be reclassified in the genus Lactococcus. Contrary to previous reports, both L. garvieae and E. seriolicida were found to be beta-haemolytic.

Determination of patulin by reversed-phase high-performance liquid chromatography with extraction by diphasic dialysis

A simple and economical method has been developed for the determination of patulin in apple juice. The sample is extracted with ethyl acetate in a diphasic dialysis system, and the extract is cleaned up by elution from a Sep-Pak cartridge. Patulin is detected and determined by reversed-phase high-performance liquid chromatography using a Novapak C18 column and an ultraviolet detector. The lower detection limit is 1 microgram l-1 and the recovery is 85% at the 20 micrograms l-1 level.