Glycidyl fatty acid esters in food by LC-MS/MS: method development.

An improved method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the analysis of glycidyl fatty acid esters in oils was developed. The method incorporates stable isotope dilution analysis (SIDA) for quantifying the five target analytes: glycidyl esters of palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2) and linolenic acid (C18:3). For the analysis, 10 mg sample of edible oil or fat is dissolved in acetone, spiked with deuterium labelled analogs of glycidyl esters and purified by a two-step chromatography on C18 and normal silica solid phase extraction (SPE) cartridges using methanol and 5% ethyl acetate in hexane, respectively. If the concentration of analytes is expected to be below 0.5 mg/kg, 0.5 g sample of oil is pre-concentrated first using a silica column. The dried final extract is re-dissolved in 250 µL of a mixture of methanol/isopropanol (1:1, v/v), 15 µL is injected on the analytical C18 LC column and analytes are eluted with 100% methanol. Detection of target glycidyl fatty acid esters is accomplished by LC-MS/MS using positive ion atmospheric pressure chemical ionization operating in Multiple Reaction Monitoring mode monitoring 2 ion transitions for each analyte. The method was tested on replicates of a virgin olive oil which was free of glycidyl esters. The method detection limit was calculated to be in the range of 70-150 µg/kg for each analyte using 10 mg sample and 1-3 µg/kg using 0.5 g sample of oil. Average recoveries of 5 glycidyl esters spiked at 10, 1 and 0.1 mg/kg were in the range 84% to 108%. The major advantage of our method is use of SIDA for all analytes using commercially available internal standards and detection limits that are lower by a factor of 5-10 from published methods when 0.5 g sample of oil is used. Additionally, MS/MS mass chromatograms offer greater specificity than liquid chromatography-mass spectrometry operated in selected ion monitoring mode. The method will be applied to the survey of glycidyl fatty acid esters in food products on the Canadian market.

Formation of acrylamide at temperatures lower than 100°C: the case of prunes and a model study.

Acrylamide concentrations in prune products--baby strained prunes (range = 75-265 µg kg(-1)), baby apple/prune juice (33-61 µg kg(-1)), prune juice (186-916 µg kg(-1)) and prunes (58-332 µg kg(-1))--on the Canadian market were determined. The formation of acrylamide in a simulated plum juice was also investigated under 'drying conditions' in an open vessel at temperatures <100°C for 24 h and under 'wet conditions' in a closed vessel at a temperature of 120°C for 1 h. Acrylamide was produced in a simulated plum juice under 'drying conditions' in amounts comparable with those found in prunes and prune juices. Acrylamide was not produced in simulated plum juice under 'wet conditions' in a closed vessel at temperature of 120°C for 1 h, but under the same condition an authentic prune juice doubled its acrylamide concentration. Formation of acrylamide in prune products was attributed to the presence of asparagine and sugars in the starting materials.

Antioxidant capacity of potato chips and snapshot trends in acrylamide content in potato chips and cereals on the Canadian market.

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 ((13)C(3)) 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.

Subchronic oral toxicity study of furan in Fischer-344 rats.

Rodent studies have shown that furan is a hepatocarcinogen. Previous studies conducted with high doses showed tumors at nearly 100% incidence at all doses. In this paper, a ninety-day gavage experiment conducted with lower doses (0.0, 0.03, 0.12, 0.5, 2.0, and 8.0 mg/kg bw) to identify a no-observed adverse effect level for hepatotoxicity and to characterize non-neoplastic effects including gross changes and histopathology, clinical biochemistry, hematology, and immunotoxicology is reported. As indicated by changes in serum biomarkers, increased liver weights and gross and histological lesions, the liver is the major target organ affected by furan. There were no changes in body weights, food consumption, or histology in other organs. Some of the serum electrolyte markers, including phosphorus, were altered. There was a significant increase in serum thyroxine and triidothyronine in males. This increase was not accompanied by histological thyroid changes. Immunophenotypic analysis showed that thymic lymphocyte maturation was altered in male rats. Although altered clinical biochemistry and hematological parameters were observed at a dose of > 0.5 mg/kg bw, mild histological lesions in the liver were observed at > 0.12 mg/kg bw. Based on this finding, a furan dose of 0.03 mg/kg bw was proposed as the no-observed adverse effect level for hepatic toxicity.

Development of an analytical method and survey of foods for furan, 2-methylfuran and 3-methylfuran with estimated exposure.

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 (> or = 20 years) were estimated at approximately 0.37 and 0.71 microg kg(-1) of body weight day(-1) respectively.

Formation of iodoacetic acids during cooking: interaction of iodized table salt with chlorinated drinking water.

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 microg l-1 range, whilst the concentration of chloroiodoacetic acid was estimated to be three to five times lower.

Methanol exposure to car occupants from windshield washing fluid: a pilot study.

UNLABELLED: Automobile occupants might be exposed to considerable amounts of methanol from previously unreported source, namely via the inhalation of vapors of winter-grade, methanol-based, windshield washing fluid that drains to the intake air ducts of the car. Air samples were collected in passenger cars during simulated operating conditions and analyzed for methanol via headspace gas chromatography-mass spectrometry, electron impact, selected ion monitoring. The method was linear in the 2-2000 ppm range. Concentrations exceeding 1000 ppm were recorded. PRACTICAL IMPLICATIONS: Using a winter-grade, methanol-based, windshield washing fluid for windshield cleaning in a passenger car can result in a methanol concentration in the air of the passenger cabin in excess of 1000 ppm. In view of the widespread use of this product, more studies are necessary to elucidate, in depth, the concentrations of methanol vapors which could be encountered in various weather and driving conditions as well as the concomitant contributing influences of car design. These studies are necessary to properly assess the hazards associated with use of the fluid and possible mitigation approaches which might include substitution of methanol by less toxic formulations.

Semicarbazide in Canadian bakery products.

Levels of semicarbazide were determined by liquid chromatography-tandem mass spectrometry using isotope dilution ((13)C(15)N(2)-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 (<1ng g(-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.

Development and validation of a headspace method for determination of furan in food.

In the past furan had been found to form in foods during thermal processing. These findings and a recent classification of furan as a possible human carcinogen prompted us to develop a simple isotope dilution method for its determination in foods. We also investigated effects of furan volatility, sample matrix and partitioning of furan between water and fat constituents of sample on the analytical determination of furan. The method is based on headspace sampling of a 2 ml vial containing 1 g of sample. For analysis, samples were spiked with d(4)-furan, homogenized in a blender at 0 degree C, with water if required, and sub-sampled to vials containing sodium sulphate. After equilibration at 30 degrees C, 50 microl of headspace was injected into the split/splitless injection port of a GC/MS (EI, SIM). The method is linear in the 0.4-1000 ng/g range with a limit of detection of 0.1 ng/g.

Antineoplastic activity of azacarbazoles. III. Synthesis and antitumor evaluation of selected 2-, 3- aza- and diazaanalogues of carbazole.

Preliminary screening of the antitumor properties of selected azacarbazoles revealed that of all the compounds tested only 2,7-diazacarbazole (compound IX) and 3,6-diazacarbazole (compound XI) caused the inhibition of Sarcoma 180 growth up to 70%. beta- and gamma-Carbolines and their derivatives in presented testing system were inactive. None of the tested compounds displayed marked activity against murine leukemias and was active in the cytotoxicity test of KB cells.