Quantitative analysis of triacylglycerol regioisomers in fats and oils using reversed‐phase high‐performance liquid chromatography and atmospheric pressure chemical ionization mass spectrometry

Abstract

Positional distribution of fatty acyl chains of triacylglycerols (TGs) in vegetable oils and fats (palm oil, cocoa butter) and animal fats (beef, pork and chicken fats) was examined by reversed-phase high-performance liquid chromatography (RP-HPLC) coupled to atmospheric pressure chemical ionization using a quadrupole mass spectrometer. Quantification of regioisomers was achieved for TGs containing two different fatty acyl chains (palmitic (P), stearic (S), oleic (O), and/or linoleic (L)). For seven pairs of 'AAB/ABA'-type TGs, namely PPS/PSP, PPO/POP, SSO/SOS, POO/OPO, SOO/OSO, PPL/PLP and LLS/LSL, calibration curves were established on the basis of the difference in relative abundances of the fragment ions produced by preferred losses of the fatty acid from the 1/3-position compared to the 2-position. In practice the positional isomers AAB and ABA yield mass spectra showing a significant difference in relative abundance ratios of the ions AA(+) to AB(+). Statistical analysis of the validation data obtained from analysis of TG standards and spiked oils showed that, under repeatability conditions, least-squares regression can be used to establish calibration curves for all pairs. The regression models show linear behavior that allow the determination of the proportion of each regioisomer in an AAB/ABA pair, within a working range from 10 to 1000 microg/mL and a 95% confidence interval of +/-3% for three replicates.

Sequential Collision- and Ozone-Induced Dissociation Enables Assignment of Relative Acyl Chain Position in Triacylglycerols

“…16 Product ion abundances can be used to assign the regiochemistry of a single TG, however, in isomeric mixtures that are common in biological extracts, careful calibration of ion abundances with isomeric composition is required. 12,15 Further complications arise where the FA identity influences the product ion abundance. [17][18][19] Rather than relying on ion abundance ratios in CID spectra, an explicit marker ion for assigning positional isomerism in TGs is desirable.…”

Rapid separation and characterisation of triacylglycerols in ostrich oil by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

“…Many analytical methods including high performance liquid chromatography (HPLC) (Andrikopoulos, 2002;Barron & Santa-Maria, 1989;Buchgraber, Ulberth, & Anklam, 2000;Buchgraber, Ulberth, Emons, & Anklam, 2004;Lee, Lee, Kim, Kim, & Kim, 2001;Lin, Woodruff, & McKeon, 1997;Peronaa, Barró nb, & Ruiz-Gutié rreza, 1998;Plattner, Spencer, & Kleiman, 1977;Rombaut, De Clercq, Foubert, & Dewettinck, 2009;Singleton & Pattee, 1984) and liquid chromatography mass spectrometry (LC-MS) (Byrdwell & Emken, 1995;Castilhoa, Costaa, Rodriguesb, Brancob, & Costab, 2004;Dugo, Kumm, Fazio, Dugo, & Mondello, 2006;Fauconnot, Hau, Jean-Marc Aeschlimann, Fay, & Dionisi, 2004;Holcapek, Velinska, Lisa, & Cesla, 2009;Leskinen, Suomela, & Kallio, 2007;Lin, Archinas, Harden, & Fagerquist, 2006;Lisa & Holcapek, 2008;Nagya et al, 2005;Segall, Artz, Raslan, Jham, & Takahashi, 2005) have been used for analysis of TAGs. Specially, non-aqueous reverse-phase HPLC (NARP-HPLC) is widely used in the TAGs separation.…”

Regiospecific analysis of TAGs using chromatography, MS, and chromatography‐MS

“…Kurvinen et al [16] developed a software package for the calculation of results. Jakab et al [32] and Fauconnot et al [33] used RP-HPLC-APCI-MS in the quantification of regioisomers of TAG. Relative ABA contents (ABA/AAB þ ABA) of the oils were calculated from the mass abundances of the [AA] þ and [AB] þ DAG fragment ions using a calibration curves.…”