title: Determination of caramel colorants' by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).
abstract: 2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5 ng ml⁻¹ (LOQ) to 500 ng ml⁻¹ with recoveries of 75.4-112.4% and RSDs of 1.5-15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25-30 µg ml⁻¹ with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2 ng ml⁻¹. For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from < LOQ to 563.9 ng ml⁻¹). 5-HMF was found at expected concentrations, except for a sherry vinegar sample (113 µg ml⁻¹), which required a high level of dilution before following the standard addition protocol.
authors: a Department of Food, Medicines and Consumer Safety , Scientific Institute of Public Health , B-1050 Brussels , Belgium.
authors: Séverine
authors: S
authors: Goscinny
authors: Vincent
authors: V
authors: Hanot
authors: Hasna
authors: H
authors: Trabelsi
authors: Joris
authors: J
authors: Van Loco
mesh_terms: D019342:Acetic Acid / Q000032:analysis / Q000191:economics; D053000:Analytic Sample Preparation Methods; D001515:Beer / Q000032:analysis / Q000191:economics; D001628:Beverages / Q000032:analysis* / Q000191:economics; D002851:Chromatography, High Pressure Liquid; D003212:Condiments / Q000032:analysis* / Q000191:economics; D005505:Food Coloring Agents / Q000032:analysis* / Q000737:chemistry; D005506:Food Contamination; D005513:Food Inspection / Q000379:methods*; D005602:France; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D007093:Imidazoles / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D015394:Molecular Structure; D015203:Reproducibility of Results; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D005505:Food Coloring Agents; D007093:Imidazoles; C008046:5-hydroxymethylfurfural; C049929:2-acetyl-4(5)-tetrahydroxybutylimidazole; D005662:Furaldehyde; D019342:Acetic Acid; C023439:4-methylimidazole; C032655:2-methylimidazole
keywords: UPLC-MS/MS; beverages; caramel colours; imidazole derivatives; sauces; standard addition