Considering that the analytical method
reported herein relies on a standard addition procedure, it was of
utmost importance to ascertain if the composition of the brominated
vegetable oil used in the spiking experiments was identical
to that used by the vendors in the preparation of their commercial
beverages. An analysis of the beverages and the brominated
vegetable oil revealed that the intensity profile of each of the
brominated triglyceride ions indicated above (TAG-Br2 to TAG-Br12)
was identical in all beverages and brominated vegetable oil
(Supplementary Figs. S1a and S1b), demonstrating the adequacy
of the standard used in the preparation of the spiked samples. As
expected, the ion chromatograms of samples stemming from soft
drinks not containing BVO were entirely devoid of these ions (data
not shown). SIR analyses conducted with each of these highmolecular-
weight BVO ions indicated that the ion at m/z 1700
offered the best compromise between signal-to-noise ratio and
precision in the integration, as assessed by the RSD of replicate
injections of a beverage sample, and was thus chosen for method
development and validation. While the use of a tandem mass
spectral technique, like single reaction monitoring (SRM), would
have probably enabled a more sensitive analysis of BVO, we opted
to develop the method using SIR in order to enable the implementation
of the methodology in laboratories where only single
quadrupole mass spectrometers may be available.