EXAMINING RESIDUES FOR EVIDENCE OF TRANQUILIZERS

It was found possible to determine the presence of phenothiazine deriv atives down to a level of about 0.2 ppb in pig sera or urine, using a commercial multi-ELISA kit. Final concentrations at the end of the wit hdrawal time and concentrations measured at the relevant injection poi nts (< 10 ppb to 100 ppm) are given. Because of the sometimes high con centrations at the injection points, which are not normally recognized but can be assumed from the serum concentrations (range 1 ppb), a mea t hygiene regulation is regarded as necessary (processing meat only) a nd this is discussed.