Gas chromatographic separation of enantiomeric amino acids and amines with α-methoxy-α-trifluoromethylpropionic acid as a chiral derivatizing agent

Determination of d- and l-enantiomers of methionine and [2H3]methionine in plasma by gas chromatography–mass spectrometry

“…Since methionine is not volatile and does not permit direct analysis on GC, it must be converted into suitable derivatives. Several derivatization methods have been reported to measure amino acids by GC-MS [17][18][19][20][21]. We have previously used MTPA-OMe derivative for separation of the leucine enantiomers [22].…”

(S)‐2‐chloro‐2‐fluoroethanoyl isocyanate, a chiral derivative of trichloroacetyl isocyanate

“…A list of recent reagents can be found, e.g., in reviews Lindner, 6 Parker,7 or Uray 8 or in recent papers by Streinz et al, 9 Weibel et al, 10 Harada et al, 11 and others. While the goal of creating new CDAs is usually to generate larger chemical shift change either by proper choice of substituents or by increasing the aromatic shielding power or by locking the conformations, even acids containing substituents that can hardly be believed to increase the rigidity of the system, e.g., perfluoro-2-propoxypropionic acid (PPPA) 12 or chlorofluoroacetic acid (CFA), 9 have been described as surprisingly efficient CDAs.…”