Determination of brominated vegetable oils in soft drinks by gas liquid chromatography

Analyses of the brominated vegetable oil in soft drinks using gas chromatography-flame ionization detector and atmospheric pressure gas chromatography-quadrupole/time-of-flight mass spectrometry

Herein, a new method for quantifying the brominated vegetable oil content in commercial soft drinks was developed, which accelerated the sample preparation process and improved analytical efficiency. First, simple and accurate chromatographic separation techniques were performed using a VF-5ht column for both GC-FID (quantitative) and APGC-QTOF (qualitative) analyses. The samples were subjected to chromatography on a reversed-phase solid-phase extraction cartridge. (PoraPak™RxnRP). Transesterification using a boron trifluoride methanol complex in methanol solution was performed. When validating this method, the analyte recovery percentages were between 82.2% and 99.9%, and the recovery and standard deviation of repeatability values were between 1.2% and 3.5%. Using an isotope library, the bromostearic acid methyl esters (9,10-dibromostearic acid methyl ester, 9,10,12,13-tetrabromostearic acid methyl ester, and hexabromostearic acid methyl ester) in the sample mixtures were qualitatively confirmed via APGC-QTOF. A novel aqueous ammonium adduct, which has not been previously reported, was also confirmed. These results indicated that this new method was simple, accurate, and also allowed for precise qualitative and quantitative confirmation as well as high reproducibility.

Simple and rapid quantification of brominated vegetable oil in commercial soft drinks by LC-MS

We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography-electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple "dilute and shoot" sample preparation. The quantification is conducted by mass spectrometry in selected ion recording mode and a single point standard addition procedure. The method was validated in the range of 5-25μg/mL BVO, encompassing the legal limit of 15μg/mL established by the US FDA for fruit-flavored beverages in the US market. The method was characterized by excellent intra- and inter-assay accuracy (97.3-103.4%) and very low imprecision [0.5-3.6% (RSD)]. The direct nature of the quantification, simplicity, and excellent statistical performance of this methodology constitute clear advantages in relation to previously published methods for the analysis of BVO in soft drinks.

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.

Mammary transfer and metabolism in the rat of halogenated fatty acids of halogenated olive oil

To assess possible incorporation of halogenated fatty acids into the neonate via the milk, a 4-day study was carried out in which lactating Wistar rats were orally dosed with either brominated olive oil (BOO) (0.6 g/kg body wt/day) or chlorinated olive oil (COO) (0.4 g/kg body wt/day) for the first 4 days. On days 1-5 inclusive 2 pups per litter were sacrificed and the stomach curd and livers analyzed for halogenated fatty acids by gas liquid chromatography (GLC). On day 5 all dams also were sacrificed and their livers and adipose tissue similarly analyzed. With BOO, brominated fatty acids (bfa) accumulated in both the milk lipids and neonate liver lipids, and appeared to plateau on day 4 at levels of 2% and 5% respectively. In contrast to the BOO in which approximately 100% of the bfa was dibromostearic (DBS), the milk bfa comprised 79% (DBS), 9% dibromopalmitic (DBP) and 12% dibromomyristic (DBM) acids, suggesting maternal metabolism to the shorter chain brominated acids. In the neonate liver lipids the bfa composition was 47% (DBS), 12% (DBP) and 41% (DBM), suggesting either further metabolism in the neonate and/or preferential accumulation of the shorter chain brominated acids. The analysis of maternal tissue indicated very low bfa residues, contrary to previous studies in non-lactating rats. Similar results were obtained with COO.