Analytical methods employed in drug residues surveillance

5 Analytical methods employed in drug residues surveillance 

Ideally, screening techniques should be relatively inexpensive and rapid, and permit a large number of samples to be analysed. For veterinary drug residues analysis the basic criteria that the screening method must meet are  

It is also desirable that a screening test should have a low incidence of false positive results. (False positives will occur if the test is sensitive to other, similar compounds - such as natural substances in the tissue - or metabolites.) A high incidence of false positives will limit the cost-effectiveness of the screening method because unnecessary and often costly confirmatory tests will need to be performed. 

Confirmatory techniques must conform to more stringent criteria than screening techniques and have a  

It is important that there is a low level of doubt about the identity of the compound being measured and a high level of certainty that the quantity determined is a true reflection of the amount actually present. To achieve this, confirmatory techniques usually employ complex separation procedures to isolate the compound of interest and require calibration procedures that involve adding known amounts of the compound to uncontaminated specimens of the material under analysis. As a final check on the validity of the method it is recommended that the method should be evaluated in a collaborative trial in a minimum of three independent laboratories against a standard reference material. 

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