Cato Brede

Increased migration levels of bisphenol A from polycarbonate baby bottles after dishwashing, boiling and brushing

Baby bottles are often made of polycarbonate plastic. Impurities remaining in the bottle from the monomer bisphenol A can migrate from the plastic bottles into baby food, thereby causing a health concern. Previous migration testing of new baby bottles showed only trace migration levels of the substance. In the present work, polycarbonate baby bottles were subjected to simulated use by dishwashing, boiling and brushing. Migration testing performed with both new and used bottles revealed a significant increase in migration of bisphenol A due to use. This finding might be explained by polymer degradation. Bisphenol A was determined in 200-ml samples of water food simulant by a method based on solid-phase extraction followed by gas chromatography coupled with mass spectrometry. The detection limit was 0.1 µg l−1. Twelve different polycarbonate baby bottles were tested by filling them with hot water (100°C) for 1 h. The mean bisphenol A level from new bottles was 0.23 + − 0.12 µg l−1, while the mean levels from bottles subjected to simulated use were 8.4 + − 4 µg l−1 (dishwashed 51 times) and 6.7 + − 4 µg l−1 (dishwashed 169 times), respectively. None of the bottles released bisphenol A at levels that exceed the recently established provisional tolerable daily intake (0.01 mg kg−1 body weight/day) in the European Union.

Analysis of phenolic compounds in six Norwegian plum cultivars (Prunus domestica L.).

Six European plum cultivars ( Prunus domestica L.) grown in Norway have been studied with respect to phenolic composition. Neochlorogenic acid was found to be the most important phenolic acid in all cultivars. Together with other phenolic acids, this compound varied significantly in amount among the cultivars. Cyanidin 3-rutinoside was found to account for >60% of the total anthocyanin content. Minor amounts of flavonols (rutin and quercetin 3-glucoside) were detected in all cultivars. Total antioxidant capacity varied from 814 to 290 micromol of Trolox 100 g(-1) of fresh weight. Measurement of total phenolic content in terms of Prussian blue complex formation revealed a method failure of magnitude order compared to results obtained by HPLC. Comparison of the response factors of a range of phenolic compounds obtained upon analysis by the Prussian blue and Folin-Ciocalteu assays revealed that the latter method returned higher yields in terms of gallic acid (GAE).

Microplasma Mass Spectrometric Detection in Capillary Gas Chromatography

A simple and miniaturized 350-kHz helium discharge for plasma mass spectrometric detection in gas chromatography (GC) has been developed. The plasma was sustained at low pressure within the end of the capillary GC column (0.32-mm i.d.) inside the ion source housing of a quadrupole mass spectrometer. This allowed direct introduction of ions from the plasma to the mass analyzer using only a repeller and electrostatic lenses to focus the ions. The plasma was sustained in only 25 mL min(-)(1) of helium, which was accepted by the mass spectrometer vacuum system. This low gas flow also served to enhance the energy density of the discharge and to produce a narrow spray of ions toward the mass analyzer. Due to the miniaturized nature of the plasma, it was operated at a low power level (2.0 W), and traces of oxygen were added to avoid deposition of carbon. With this new concept for GC plasma mass spectrometric detection, chlorine was successfully monitored down to the 2.2 pg s(-)(1) level without interference from elements like C, S, P, O, F, and N.

Improved sample extraction and clean-up for the GC-MS determination of BADGE and BFDGE in vegetable oil

A straightforward method was established for the determination of migration contaminants in olive oil with a special focus on the two can-coating migration compounds bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE). The preferred sample preparation was a single liquid-liquid extraction of compounds from the oil into 20% (v/v) methanol in acetonitrile, followed by clean-up with solid-phase extraction on aminopropyl bonded to silica. This purification procedure selectively removed all free fatty acids from the extracts without removing phenolic compounds of interest. The solid-phase extraction columns were used many times by implementing a procedure of washing out the strongly retained fatty acids with 2% acetic acid in methanol. Gas chromatography coupled with full scan (m/z 33-700) electron ionization mass spectrometry was used for the determination of several model compounds in olive oil samples. BADGE and BFDGE could be determined in the 0.05-2 mg kg−1 range in oil samples with a relative SD of <6% (six replicates). The method was used in an enforcement campaign for the Norwegian Food Control Authority to analyse vegetable oil samples from canned fish-in-oil.

Simultaneous Element‐Selective Detection of C, F, Cl, Br, and I by Capillary Gas Chromatography Coupled with Microplasma Mass Spectrometry

Simultaneous element-selective detection of the halogens and carbon was accomplished with capillary gas chromatography coupled with microplasma mass spectrometry. The microplasma ion source was a radio frequency plasma contained inside the last 4–5 cm of the 0.32 mm i.d. fused silica capillary column. The ion source was located inside the high vacuum housing of the MS, and only the GC carrier gas (2.3 mL min−1 of helium) was used for plasma generation. Atomic ions were detected in the positive mode. Detection limits were in the low picogram area, and the selectivity to carbon ranged from 8×102 for fluorine to higher than 104 for the other halogens. By introduction of both hydrogen and oxygen as reagent gases, peak tailing was avoided by suppression of analyte reactions with the silica walls of the ion source. Special attention was given to the fluorine-selective detection due to an interfering background species at m/z 19, assumed to be H3O+ originating from the reagent gases. The background signal was minimized by careful control of the power level.

Capillary gas chromatography coupled with microplasma mass spectrometry for organotin speciation

Gas chromatography was coupled with microplasma mass spectrometry for selective detection of organotin compounds. The microplasma ion source was a capacitively coupled radiofrequency helium plasma, which was located inside the high vacuum area of the mass spectrometer. Only 1-3 ml min-1 of helium carrier gas from the gas chromatograph was necessary for sustaining the plasma while 0.15-1.5 ml min-1 of hydrogen was added as reagent gas. Hydrogen was applied for prevention of carbon deposition and served to minimize the interactions between tin and the fused-silica inner surface of the microplasma ion source. Both carbon and tin were detected as positively charged atomic ions, which were expelled from the microplasma ion source and directly focused by electrostatic lenses towards the quadrupole mass analyzer. Tin exhibited high selectivity to carbon (> 10(4)) and a detection limit of 3.5 pg s-1.

Capillary gas chromatography coupled with microplasma mass spectrometry : Improved ion source design compatible with bench-top mass spectrometric instrumentation

Capillary gas chromatography was performed with mass spectrometric detection using a novel microplasma ion source for operation in an element-selective mode. The ion source was a 350 kHz radio frequency helium plasma, which was sustained inside the 4 cm end of a 0.32 mm i.d. fused silica capillary column, and located inside the high vacuum chamber of the quadrupole mass spectrometer. Due to the low volume of the ion source, a stable low pressure discharge was produced utilizing only the 2.25 mL min−1 of GC carrier gas (helium) for plasma support. Small amounts of oxygen (0.1–0.2% v/v) were added to the plasma gas in order to prevent carbon deposits and to enhance signal-to-noise ratios. Chlorine and bromine were selectively detected at the 5–20 pg s−1 level (S/N = 2), and both produced a response that was linear within 3 orders of magnitude.

Identification of diflubenzuron by packed-capillary supercritical fluid chromatography-mass spectrometry with electron-capture negative ionization

Abstract The thermolabile insecticide diflubenzuron [1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea] was successfully chromatographed by supercritical fluid chromatography on a 320 μm I.D. Inertsil C 8 column using neat carbon dioxide as mobile phase. Detection and electron-capture negative ionization (ECNI) mass spectrometric characterization were accomplished using a double focusing mass spectrometer with a modified ion source and coaxial direct fluid introduction. Detection limits of 1.0 μg/ml and 0.03 μg/ml were obtained in full-scan and selected-ion monitoring (SIM) mode, respectively. The restrictor heater temperatyre was found to have a major influence on the signal intensity and fragmentation pattern, as thermal degradation was believed to take place or be initiated on the hot restrictor wall. The reactive abundance of the molecular ion amounted to 100% using restrictor temperatures of 160°C and 170°C, while it was completely absent at 190°C. At the lower temperatures, [M - HF] −• was the most significant fragment ion.