Special products for determination of pesticides in food samples. QuEChERS method and pre-mixes. Within a few years after its development by Anastassiades et al. the QuEChERS method has gained a leading position for the determination of pesticide residues in food samples by GC-MS or LC-MS, allowing rapid and cheap clean-up of strongly matrix-contaminated samples. For optimizing the extraction of pH-dependent compounds, for minimizing decomposition of sensitive substances, and for broadening the matrix spectrum, different modifications of the QuEChERS method have been elaborated. MACHEREY-NAGEL offers a number of individually weighed and premixed extraction (buffered or non-buffered) and clean-up mixtures, specially composed for different sample matrices.