Taurodeoxycholic acid
Taurodeoxycholic acid is a bile acid. This compound is a closely related isomer of Taurochenodeoxycholic acid and Tauroursodeoxycholic acid sharing the exact molecular formula and molecular weight. Mass Spectrometry Interference with PFOS Benskin and colleagues (https://pubs.acs.org/doi/pdf/10.1021/ac070802d) published in 2007 an article identifying Taurodeoxycholic acid and isomers as mass spectrometry interferents with PFOS (Perfluorooctanesulfonic acid) as the two compounds share the m/z transition of 498-80. The molecular weight of PFOS and taurodeoxycholic acid and isomers are similar enough in molecular weight that most low resolution Triple quadrupole mass spectrometer are unable to distinguish these two chemicals from each other. Additionally both compounds share a Sulfonate group (leading to the m/z 80 loss) in the common mass spectrometry transition. Reiner and colleagues https://pubs.acs.org/doi/pdf/10.1021/es800770f found these bile acid compounds in chicken eggs and suggest that monitoring for m/z 99 (FSO3 loss) as does Benskin and colleagues noted above. Compounding the issue is PFOS is widely distributed in global wildlife, and analysis of blood, liver and flesh of monitored wildlife will likely also contain these bile acids. Therefore caution must be taken in sample cleanup, analysis and mass spectra interpretations. Strynar and colleagues ASMS Strynar et al., 2009 demonstrated the presence of these cholic