Analytical Methods Simultaneous determination of acrylamide, asparagine and glucose in food using short chain methyl imidazolium ionic liquid based ultrasonic assisted extraction coupled with analyte focusing by ionic liquid micelle collapse capillary electrophoresis Deia Abd El-Hady a,b,⇑ , Hassan M. Albishri c a Chemistry Department, Faculty of Science, University of Jeddah, P.O. 80327, 21589 Jeddah, Saudi Arabia b Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt c Chemistry Department, Faculty of Science, King Abdulaziz University, 80203 Jeddah, Saudi Arabia article info Article history: Received 5 February 2014 Received in revised form 7 March 2015 Accepted 13 May 2015 Available online 14 May 2015 Chemical compounds studied in this article: Acrylamide (PubChem CID: 6579) Asparagine (PubChem CID: 6267) Glucose (PubChem CID: 107526) (PubChem CID: 6579) 1-Butyl-3-methylimidazolium bromide 1-Butyl-3-methylimidazolium tetrafluoroborate 1-Butyl-3-methylimidazolium nitrate 1-Butyl-3-methylimidazolium acetate 1-Ethyl-3-methylimidazolium bromide 1-Hexyl-3-methylimidazolium bromide 1-Octyl-3-methylimidazolium bromide Keywords: Acrylamide Asparagine Glucose Bread Ionic liquid Capillary electrophoresis abstract Acrylamide (AA) is a known lethal neurotoxin and carcinogen. AA is formed in foods during the browning process by the Maillard reaction of glucose (GL) with asparagine (AS). For the first time, the simultaneous online preconcentration and separation of AA, AS and GL using analyte focusing by ionic liquid micelle collapse capillary electrophoresis (AFILMC) was presented. Samples were prepared in a 1-butyl-3-methylimidazolium bromide (BMIMBr) micellar matrix with a conductivity 4 times greater than that of the running buffer (12.5 mmol L À1 phosphate buffer at pH 8.5). Samples were hydrodynam- ically injected into a fused silica capillary at 25.0 mbar for 25.0 s. Separations were performed by applying a voltage of 25.0 kV and a detection at 200.0 nm. To sufficiently reduce BMIMBr adsorption on the interior surface of capillary, an appropriate rinsing procedure by hydrochloric acid and water was optimized. AFILMC measurements of analytes within the concentration range of 0.05–10.0 lmol L À1 achieved ade- quate reproducibility and accuracy with RSD 1.14–3.42% (n = 15) and recovery 98.0–110.0%, respectively. Limits of detections were 0.71 ng g À1 AA, 1.06 ng g À1 AS and 27.02 ng g À1 GL with linearity ranged between 2.2 and 1800 ng g À1 . The coupling of AFILMC with IL based ultrasonic assisted extraction (ILUAE) was successfully applied to the efficient extraction and determination of AA, AS and GL in bread samples. The structure of ILs has significant effects on the extraction efficiency of analytes. The optimal extraction efficiency (97.8%) was achieved by an aqueous extraction with 4:14 ratio of sample: 3.0 mol L À1 BMIMBr followed by sonication at 35 °C. The proposed combination of ILUAE and AFILMC was simple, ecofriendly, reliable and inexpensive to analyze a toxic compound and its precursors in bread which is applicable to food safety. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction It is well known that baking is a common way to prepare bread with a desirable taste and low possibility of microbial contamina- tion. However, baking can lead to the formation of acrylamide (AA) in carbohydrate-rich food products (Nielsen, Granby, Hedegaard, & Skibsted, 2006; Elmore et al., 2015). AA is a known lethal neuro- toxin and animal carcinogen and can cause damage to male repro- ductive glands (Mottram, Wedzicha, & Dodson, 2002; Stadler et al., 2002). AA is also known as a neutral monomer due to the difficult ionization of its amide group. AA is formed during the browning process by the Maillard reaction of reducing glucose (GL, pK a = 12.3) with an amino acid asparagine (AS, pK a1 = 2.02 & pK a2 = 8.8) at temperatures above 120 °C(Mottram et al., 2002; Stadler et al., 2002). Therefore, the simultaneous analysis of AA, AS and GL in food by capillary electrophoresis (CE) is of great inter- est. However, this analysis requires special circumstances due to http://dx.doi.org/10.1016/j.foodchem.2015.05.047 0308-8146/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Chemistry Department, Faculty of Science, University of Jeddah, P.O. 80327, 21589 Jeddah, Saudi Arabia. E-mail addresses: deiaabdelhady@yahoo.com, deiaeldin@aun.edu.eg (D. Abd El-Hady). Food Chemistry 188 (2015) 551–558 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem