QUALITATIVE OR QUANTITATIVE METHODS FOR RESIDUE ANALYSIS

Qualitative methods are used for illegal drugs (e.g, hormones) which h ave a so-called zero tolerance (i.e, the presence of even a very small amount is not tolerated). In practice a limit of determination is use d to prove the presence or absence of an analyte. Quantitative analysi s is necessary especially for residues with a maximum residue limit (M RL). The method used in this case must have a limit of quantification (much) lower than the MRL. In any case, quality criteria must be fulfi lled before quantification. In this investigation the pro's and con's of different strategies towards the use of qualitative and quantitativ e methods are discussed from the point of view and the daily experienc e of routine control in two field laboratories and one national refere nce laboratory.