Slide 8 of 49
Notes:
Most samples examined for residues of veterinary medicines and drugs of abuse, are found to be negative. The need to deliver cost-efficient control together with rapid turnaround times to allow for effective field investigation, requires a tiered approach to samples analysis.
Screening methods are designed to rapidly screen samples for the absence of a residue, or the absence of a residue above a certain limit. In some instances, an indication of the concentration or identity of the residue is given by these methods.
Screening techniques employed for veterinary residues include :
- Antimicrobial inhibition assays
- ELISA screening for antibiotics, anthelmintics and ionophores,
- ELISA and RIA screening for anabolic hormones,
- ELISA screening for beta-agonists,
- HPTLC screening for sulphonamides and thyreostats,
- HPLC screening of avermectin residues,
- Screening for beta-agonists by gas chromatography / mass spectrometry,
- Screening for natural hormones by DELFIA.
In some instances, for example in the chromatographic methods, quantitative data is generated simultaneously. In other cases, the answer is simply positive or negative with an indication of compound identity.
