Adam Becalski

The concentration of acrylamide was measured in selected varieties of five brands of potato chips and breakfast cereals over a 5-year period. Most of the products were purchased in one locality in Canada. Samples were analysed by an isotope dilution (¹³C₃) acrylamide method. They were extracted with water, partitioned with dichloromethane, filtered through a 5 kDa centrifuge filter, cleaned-up on HLB Oasis polymeric and Accucat mixed mode anion and cation exchange SPE columns, and analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The acrylamide concentration in potato chips varied from 106 to 4630 ng g⁻¹, while values in cereals varied from 50 to 347 ng g⁻¹. Wide variations were observed between brands, within brands over time, and between lots of the same brand. A subset of potato chip samples was analysed for in vitro antioxidant activity. No relationship was found between antioxidative capacity of potato chips and their acrylamide content.

Furan has been found to form in foods during thermal processing. These findings, a classification of furan as a possibly carcinogenic to humans, and a limited amount of data on the concentration of furan in products on the Canadian market prompted the authors to conduct a survey of canned and jarred food products. Methyl analogues of furan, 2-methylfuran and 3-methylfuran, were analysed concurrently with furan via a newly developed isotope dilution method, as these analogues were detected in foods in the authors’ earlier work and are likely to undergo a similar metabolic fate as furan itself. The paper reports data on 176 samples, including 17 samples of baby food. The vast majority of samples were packaged in cans or jars. Furan was detected above 1 ng g⁻¹ in all non-baby food samples with a median of 28 ng g⁻¹ and concentrations ranging from 1.1 to 1230 ng g⁻¹. Also, 96% of these samples were found to contain 2-methylfuran above 1 ng g⁻¹ with a median of 12.8 ng g⁻¹ and a maximum concentration of 152 ng g⁻¹, while 81% of samples were found to contain 3-methylfuran above 1 ng g⁻¹ with a median of 6 ng g⁻¹ and a maximum concentration of 151 ng g⁻¹. Similarly, furan was detected above 1 ng g⁻¹ in all baby food samples with a median of 66.2 ng g⁻¹ and concentrations ranging from 8.5 to 331 ng g⁻¹. Also, 100% of these samples were found to contain 2-methylfuran above 1 ng g⁻¹ with a median of 8.7 ng g⁻¹ and a maximum concentration of 50.2 ng g⁻¹, while 65% of samples were found to contain 3-methylfuran above 1 ng g⁻¹ with a median of 1.6 ng g⁻¹ and a maximum concentration of 22.9 ng g⁻¹. Additionally, three coffee samples were analysed ‘as is’, without brewing, and were found to have high levels of furans, especially 2-methylfuran, at a maximum of 8680 ng g⁻¹. Using this data set, dietary exposures to furan and total furans were calculated. Average furan and total furan intakes by adults (≥20 years) were estimated at approximately 0.37 and 0.71 µg kg⁻¹ of body weight day⁻¹ respectively.

An automated, simple, and reproducible method was developed for the determination of benzene in soft drinks, based on isotope dilution headspace gas chromatography/mass spectrometry in the selected-ion monitoring mode. The method was used to assess benzene levels in samples of 124 soft drinks and beverages. Benzene was not detected in 60% of the 124 products. The average benzene levels in 6 products exceeded the Canadian maximum acceptable concentration of 5 g/L for benzene in drinking water, and 2 of the 6 products had benzene levels above the World Health Organization guideline of 10 g/L. The highest level of benzene, 23 g/L, was found in a soft drink product specifically marketed to children.

Iodoacetic and chloroiodoacetic acids were formed when municipal chlorinated tap water was allowed to react with iodized (with potassium iodide) table salt or with potassium iodide itself. Iodoacetic acid was recently shown to be a potent cytotoxic and genotoxic agent. For analysis, samples were extracted with t-amyl methyl ether and converted to the corresponding methyl esters using methanol and sulfuric acid. The concentration of iodoacetic acid was determined by gas chromatography-mass spectrometry (GC-MS) using an authentic standard. The identities of iodoacetic and chloroiodoacetic acids were further confirmed by gas chromatography-high-resolution mass spectrometry (GC-HRMS). Certain influences of sodium hypochlorite and humic acid as well as the concentration of potassium iodide on the yields of these acids were investigated. The concentration of iodoacetic acid in tap water samples boiled with 2 g l⁻¹ of iodized table salt was found to be in the 1.5 µg l⁻¹ range, whilst the concentration of chloroiodoacetic acid was estimated to be three to five times lower.

Levels of semicarbazide were determined by liquid chromatography-tandem mass spectrometry using isotope dilution (¹³C¹⁵N₂-semicarbazide) methodology, and they were measured, after hydrolysis in 0.125 M hydrochloric acid and derivatization with 2-nitrobenzaldehyde, as a sum of free and bound semicarbazide. Levels of semicarbazide in 11 bakery products, which were sampled at three time intervals from the same source, varied from not detected (−1) to 560 ng g⁻¹. In some instances, concentrations of semicarbazide varied between batches of the same product, at times more than tenfold, suggesting that the addition of azodicarbonamide to the same product is not standardized in many baking establishments.

Furan was previously detected in foods that had undergone thermal treatment. Because furan is now classified as a possible human carcinogen, a model system was developed to investigate the origins of furan. Also, a simple, rapid isotope dilution (d₄-furan) headspace method was developed to measure furan. Two pathways of furan formation have been identified in the model systems tested so far. The first is the oxidation of polyunsaturated fatty acids at elevated temperatures, and the second is linked to the decomposition of ascorbic acid derivatives. The analytical procedure, based on the use of a 50 μL injection (from the headspace of a 1.5 mL vial containing 0.5 mL water) into the split/splitless injection port of a gas chromatograph/mass spectrometer (electron ionization, selected-ion monitoring), showed linearity in the 10–1000 ng/g range with a limit of detection of 1 ng/g.

Recent concerns surrounding the presence of acrylamide in many types of thermally processed food have brought about the need for the development of analytical methods suitable for determination of acrylamide in diverse matrices with the goals of improving overall confidence in analytical results and better understanding of method capabilities. Consequently, the results are presented of acrylamide testing in commercially available food products — potato fries, potato chips, crispbread, instant coffee, coffee beans, cocoa, chocolate and peanut butter, obtained by using the same sample extract. The results obtained by using LC-MS/MS, GC/MS (EI), GC/HRMS (EI) — with or without derivatization — and the use of different analytical columns, are discussed and compared with respect to matrix borne interferences, detection limits and method complexities.

Semicarbazide was previously found in foods that were in contact with rubber gaskets foamed at high temperatures with a blowing agent azodicarbonamide. Because azodicarbonamide is an approved flour additive in certain countries, we set out to ascertain if semicarbazide is formed during the baking process from flours containing that additive. The levels of semicarbazide in baking flour treated with azodicarbonamide and bread baked from such flours were determined by isotope dilution (¹³C¹⁵N₂-semicarbazide) liquid chromatography electrospray tandem mass spectrometry (LC-MS/MS). The samples were homogenized with HCl, extracted with n-pentane, derivatized with 2-nitrobenzaldehyde, and the derivative was extracted with ethyl acetate. After solvent exchange to 10% acetonitrile in water containing 0.1% acetic acid, the samples were analyzed using a 2.1 mm × 150 mm C18 column eluted with 2 mM ammonium formate in water/methanol (40:60). Semicarbazide was formed during the dry heating of commercial azodicarbonamide-containing flours at temperatures of 150−200 °C reaching levels of 0.2 mg/kg. Similar levels of semicarbazide were found in the crusts of breads made from azodicarbonamide-treated flour. Keywords: Semicarbazide; azodicarbonamide; 2-nitrobenzaldehyde; flour; LC-MS/MS

The free amino acid profile and sugar (fructose, glucose, and sucrose) composition were determined in potato samples selected to give a large range of variation (a total of 66 samples). From these samples French fries were produced in a laboratory-scale simulation of an industrial process followed by a finish fry at 180 °C for 3.5 min using a restaurant fryer. The final product was blast frozen and analyzed for acrylamide. Acrylamide was detected in all samples, but its concentration varied significantly from 50 to 1800 ng/g. For isotope dilution (¹³C₃) acrylamide analysis, samples were extracted with water, cleaned up on HLB Oasis polymeric and Accucat mixed mode anion and cation exchange SPE columns, and analyzed by LC-MS/MS. Statistical analysis of the data indicates that the effect of sugars and asparagine on the concentration of acrylamide in French fries is positive and significant (p < 0.001). It appears that one of the ways acrylamide formation in French fries can be effectively controlled is by the use of raw products with low sugar (and to a lesser degree, asparagine) content. Keywords: Acrylamide; potato; glucose, fructose, sucrose; asparagine; Maillard reaction, LC-MS/MS