chemistry, an argument to speed up the application of recent methods is the drastically reduced solvent consumption making them environmentally friendly.

An extremely important aspect is quantification. The degree of accuracy and precision will always remain a function of the number of targets to be determined. Single residue methods and sMRMs provide more accurate results than MRMs. For single residue methods and sMRMs, often labelled standards are available that can be added to the sample before or during the sample preparation steps. Examples are the determination of chlormequat in fruit and vegetables, of CAP in honey, of dioxins in milk, of nitrofurans in fish. In MRMs compromises have to be made but this does not automatically mean that the obtained data are less important. In the first instance, a semi-quantitative idea is obtained allowing one to decide whether or not precise quantification is needed. When the concentration is far below the MRL value further work in this respect is a waste of time. The main advantage of MRM is that a broad range of contaminants and residues is screened and when positive elucidation, both in terms of nature and close to the MRL level, is obtained accurate quantification can be made by standard addition.

0 0

Post a comment