CHROMABOND® QuEChERS extraction buffer mixes / clean-up mixes

QuEChERS method and pre-mixes
Within a few years after its devleopment by Anastassiades et al. the QuEChERS method has gained a leading position for determination of pesticide residues in food by GC-MS or LC-MS allowing rapid and cheap clean-up of strong matrix-contaminated samples.
Standard clean-up of food samples
10 g sample are homogenised with 10 ml acetonitrile. After adding the internal standard the sample is shaken with 4 g MgSO₄ and 1 g NaCI and afterwards centrifuged. 1 ml of the supernantant is spiked with 25 mg CHROMABOND^® Diamino and 150 mg MgSO₄ and shaken again. After centrifugation the supernatant is injected into the GC/MS.

For optimising the extraction of pH-dependent compounds, for minimising decomposition of sensitive substances and for broadending the matrix spectrum, different modifications of the QuEChERS method have been elaborated. Extraction mixtures for sample preparation for determination of pesticides in food samples.

MACHEREY-NAGEL offers a number of individually weighed and pre-mixed buffers and extraction mixtures, specially composed for different sample matrices.
Mix I and Mix II are extraction mixtures, Mix III to Mix VI are clean-up mixtures.

The food samples will be extracted with either Mix I or Mix II.
Afterwards they will be purified with one of the following mixtures:

• Mix III (samples with low fat content; e.g. apples, strawberries),
• Mix IV (moderate content of chlorophyll and carotinoids; e. g. carrots, lettuce),
• Mix V (high content of chlorophyll and carotinoids; e. g. bell peppers, spinach),
• Mix VI (high fat content; e. g. avocados).