Mass spectra of methyl esters of brominated fatty acids and their presence in soft drinks and cocktail syrups.

RATIONALE: Brominated vegetable oil (BVO) is frequently used as a solubility transmitter in soft drinks. Being banned in Europe and Japan but permitted in the United States and Canada, there is a need for analytical methods suitable for use in food control. Brominated fatty acids in BVO are usually determined by gas chromatography (GC) after their conversion into the corresponding methyl esters. METHODS: GC with mass spectrometry (MS) was used to record the electron ionization (EI) and negative ion chemical ionization (NICI) mass spectra of relevant brominated fatty acid methyl esters synthesized for this purpose. Brominated fatty acids obtained from transesterified BVO from soft drink and syrup samples were also analyzed. RESULTS: GC/NICI-MS was the most sensitive method for the detection of brominated fatty acids but GC/EI-MS was found to be more suited for quantification due to the formation of more selective fragment ions in the higher mass range. Suitable ions were selected for determination of the methyl esters of brominated fatty acids in the selected ion monitoring (SIM) mode. Artifacts produced by the transesterification of BVO with boron trifluoride were observed and discussed. BVO was also quantified in three syrup samples commercially produced for use in cocktails/long drinks. In one of the syrup samples that tested positive, BVO was not labelled in the ingredient list. Bromination experiments produced evidence that one or more Br2 -18:0 isomers identified as a shoulder peak of threo-9,10-dibromooctadecanoic acid in several soft drink and syrup samples originated from the bromination of partly hydrogenated plant oil. CONCLUSIONS: BVO was determined for the first time in syrup samples. Attention should be paid to the problem of BVO occurring unlabeled in soft drinks and cocktail syrups imported from North America.

Hydrodebromination of decabromodiphenyl ether (BDE-209) in cooking experiments with salmon fillet.

Polybrominated diphenyl ethers (PBDEs) are environmental contaminants regularly detected in biota and food. Seafood has been identified as the major dietary source for human uptake. Fish is predominantly consumed after cooking, and this process may alter the actual human intake of contaminants. This study thus aimed to investigate the fate of PBDEs in this cooking process. Heating of fish fortified with 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) at typical cooking conditions (200 °C, in plant oil) resulted in a decrease of its concentration in favor of the formation of lower brominated congeners. After 15 min, ∼25% of BDE-209 was transformed into nona- to octabrominated congeners. The major transformation route was BDE-209 → BDE-206 → BDE-196 and BDE-199. Low amounts of heptabrominated congeners as well as one hexabromodibenzofuran and a heptabromodibenzofuran isomer were also detected. However, penta- and tetrabrominated diphenyl ethers were not observed, and heating of BDE-47 did not produce new transformation products.

Heating of BDE-209 and BDE-47 in plant oil in presence of o,p'-DDT or iron(III) chloride can produce monochloro-polybromo diphenyl ethers.

Heating processes of food can alter the concentrations and composition of organohalogen compounds. In this study the fate of two polybrominated diphenyl ether (PBDE) congeners, decabromodiphenyl ether (BDE-209) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was analyzed when heated in plant oil with and without additional compounds. When the PBDEs were heated in pure plant oil, no transformation was observed. Heating of decabromodiphenyl ether (BDE-209) together with ortho,para'-dichlorodiphenyltrichloroethane (o,p'-DDT) or iron(III) chloride in plant oil resulted in the formation of monochloro-nonabromodiphenyl ethers (Br(9)Cl-DEs). Almost 10% of the initial amount of BDE-209 was transferred into Br(9)Cl-DEs. Heating BDE-47 in the presence of iron(III) chloride produced two monochlorinated transformation products which were tentatively identified as 2,2',4-tribromo-4'-chlorodiphenyl ether (4'-Cl-BDE-17) and 2,4,4'-tribromo-2'-chlorodiphenyl ether (2'-Cl-BDE-28). However, the reactivity was smaller and no Br→Cl exchange was observed with o,p'-DDT. The conditions used in our experiments (200 °C; heating 30 min-3 h) indicate that such reactivity may also occur during cooking of fish, meat and other food samples.