An automated HPLC determination of meticlorpindol in eggs with UV absorbance detection, using on-line dialysis and pre-concentration as sample clean-up; occurrence in and carry over to eggs.

A fully automated HPLC determination of the coccidiostat meticlorpindol in whole egg, egg white and yolk is described. The sample homogenate is dialysed on-line against water. The dialysate is concentrated on-line on a short reversed-phase (RP) column. The contents of this column are transferred to the reversed-phase analytical column by means of the mobile phase. Meticlorpindol is detected using an absorbance detector at 270 nm. Linear calibration graphs are obtained in the range 40-900 ng/g in whole egg and egg white (detection limit 10 ng/g) and 80-1800 ng/g in yolk (detection limit 20 ng/g). Out of 111 commercially obtained egg samples 12 contained meticlorpindol with levels varying from 10 to 433 ng/g. A group of laying hens, kept in cages, received 10 mg/kg of Lerbek (meticlorpindol and methylbenzoquate; Dow Chemical) in the feed for 10 days. Meticlorpindol residues in the eggs rose to a level of 622 ng/g. Meticlorpindol was found in the eggs until 6 days after withdrawal of the medicated feed. Another group received 110 mg/kg in the feed. Meticlorpindol residues rose to levels of 4480 ng/g in the eggs, 5880 ng/g in the egg white and 2660 ng/g in the yolk. Meticlorpindol was found in the eggs and the egg white until 14 days and in the yolk until 8 days after withdrawal of the medicated feed.

[Automated determination of 4,4'-diaminodiphenylsulfone (DDS) and acetyl metabolites (MADDS and DADDS) in milk with the FAST-LC system]. / Automatisierte Bestimmung von 4,4'-Diaminodiphenylsulfon (DDS) und Acetylmetaboliten (MADDS und DADDS) in Milch mit dem FAST-LC-System.

With the described method it is possible to determinate residues of Dapsone (DDS) and its acetylated metabolites (mono- and diacetyldapsone) in milk. The determination is being carried out with a FAST-LC system (Fully Automated Sample Treatment Liquid Chromatography). The purification is a combination of dialysing the milk against water and absorption of the nonpolar components from the dialysate on the preconcentration column of the LC-system used (RP, 40 microns). With back-flush, the concentrate is being injected into the analytical column (RP-8, 5 microns). The detection is being carried out with the help of a UV-absorbance detector, at a wavelength of 296 mm. The detection limit is approximately 2 micrograms/l (DADDS: 5 micrograms/l). The required amount of the sample is 5 ml. The recovery, reproducibility and linearity for the three components in milk are good.