Acrylamide is a chemical contaminant naturally formed in processed foods mainly through the Maillard reaction. Due to its toxicological properties, this compound has been classified as “probably carcinogenic for humans”. The major sources of dietary acrylamide are potato products, cereals and coffee; therefore, it is necessary to develop robust methods to monitor the levels of the contaminant in these foods. Special attention should be paid to the adaptation of such protocols to complex matrices after in vitro gastrointestinal digestion, since enzymes and fluids added during this process could interfere with acrylamide identification and quantitation. The aim of this study was to optimize and validate an analytical method for determining acrylamide by liquid chromatography-tandem mass spectrometry analysis (LC-ESI-MS/MS) in potato and cereal-based products after a standardized in vitro digestion process (INFOGEST methodology). Analytical separation of acrylamide from digested foods was performed by HPLC using an Inertsil ODS-3V column followed by MS/MS, with [13C3]-acrylamide as an internal standard. The extraction method was based on Mesias and Morales with some modifications. Signals at m/z 72–55 and m/z 75–58 were isolated for acrylamide and (13C3)-acrylamide, respectively. The chromatographic results showed a double peak at the m/z 72–55 transition, at the same retention time as the acrylamide present in the digests (6.6 min), suggesting the presence of an interference in the extracts. Such interference also appeared in the blank after the intestinal phase of digestion, probably associated with the enzyme pancreatin added during this step. In order to separate the interference and be able to quantify the acrylamide, different modifications of the determination method were tested, both in the extraction of the compound and in the injection conditions. Separation using ultrafiltration or precipitation with trifluoroacetic acid was discarded, since only high molecular weight compounds would be removed with these methods, probably without affecting the interference associated with low molecular weight. Since slight acidic conditions during sample extraction could promote the protonation of the interference, the clean-up with Oasis MCX solid-phase extraction (SPE) cartridge was checked without further improvement. Additionally, the injection volume was optimized to 5 μL to reduce the interference. To achieve greater specificity in the identification of acrylamide, a new transition was tested (m/z 72–27), including ion 27 as a qualifier ion. This step required applying higher collision energy (11.0 V instead of 9.0 V). It allowed the elimination of the interference, obtaining the isolated acrylamide peak for its quantification. Ultimately, an acetonitrile 50% gradient step was added at the end of each injection to clean the column between samples. The described method demonstrated satisfactory precision (< 10%), repeatability (< 10%), and accuracy (recovery between 85 and 110%). Limit of quantification (LOQ) for measuring acrylamide was 15 μg/kg. The present results confirm that this optimized method meets the criteria of EU Commission Recommendations (No. 2019/1888), on the monitoring of acrylamide levels in food and is selective and suitable for determination of the contaminant in complex matrixes, as food digests, removing compounds interfering with acrylamide identification.

This work is part of the R&D project ACRINTAKE (RTI2018–094402-B-I00), financed by MCIN/AEI/10.13039/501100011033/ and "FEDER, A way to make Europe", and partially financed by the Community of Madrid and European funding from the FSE and FEDER programs (project S2018/BAA-4393, AVANSECAL-II-CM).

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.

Peer reviewed