Critical factors and pitfalls affecting the extraction of acrylamide from foods: An optimisation study

A stepwise study of common factors for the extraction of acrylamide (AA) from relevant food matrices was performed. The investigated extraction factors were sample particle size (fine or coarse), defatting (yes or no), extraction solvent (water or water/methanol), homogenisation by Ultra Turrax (yes or no), extraction temperature (25 or 60 °C) and extraction time (5 min to 17 h). An optimised method comprised the use of fine particles (<1000 μm), water as the extraction solvent and shaking of the sample for 45 min at 25 °C. This extraction method was suitable for all tested matrices (coffee, crispbread, mashed potatoes, milk chocolate and potato crisps). The analytical results (from LC-MS/MS analysis after SPE clean-up) correlated well with those obtained by the original, more labour-intensive, extraction procedure and there was excellent agreement with the assigned AA levels of several proficiency test samples analysed for evaluation. Defatting and additional homogenisation by Ultra Turrax did not increase the AA yield when other factors were set to appropriate levels. In general, the study indicates that incomplete extraction is the most likely cause of erroneous results. This might occur when the food is not sufficiently macerated, when water/methanol is used as the extraction solvent, and when using a short extraction time or low extraction temperature, especially when these conditions are combined. Formation of AA during the extraction procedure is another possible error source, though it was not seen under any of the experimental conditions employed when a fructose-enriched blank potato tissue was extracted.