Aminoácidos

Capillary GC of Amino Acids as tert-Butyldimethylsilyl Derivatives

J. Lawrence, F. 1. Onuska, R. W ilkinson, a nd B . K. Afghan,
Chemosphere 15 (9-12) (1986) 1085.
B . K. Afghan, J. Carron, P. D. Goulden, J. Lawrence, D. Leger,
F, 1. Onuska, J. Sherry, and R. Wilkinson, Canad. J. Chem. 65
(5) (1987) 1086.

F. 1. O nuska and K. Terry, Internal Report NWRl - 1 981.
Ch. Rappe, Environ.Sci. Technol. 18 ( 1984) 78A.
L. G. Blornberg, HRC & CC 7 (19 84) 232.
M. L. Lee, R. C. Kong, C. L. Woolley, and J. S. Bradshaw,
J. Chromatogr. 2 2 (1984) 136.

[7]

H.-R. Buser and Ch. Rappe, Anal. Chem. 52 (1980) 2057.

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F. 1. O nuska, J. Chromatogr. 289 (1984) 207.

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References

B . K . Afghan, R. J. Wilkinson, J. Sherry, and J. F. Ryan, Internal
Report - NWRl - 1984.[lo] M.-F. Gonnord, G. Guiochon, and F. 1. O nuska, Anal. Chem.
55 (1983) 2115.

[ I 11 R. J. Norstrom, D. J Hallett, M. Simon, M. Mulvihill, in
Chlorinated Dioxins and Related Compounds, 0. Hutzinger,
R. W . Frei, E . Merian, F. Pocchiari, eds; Pergamon Press,
Oxford, U.K. (1982), p 173.
[12] F. 1. O nuska, s ubmitted for publication to HRC & CC.

Capillary Gas Chromatography of AminoAcids as Their
tert-Butyldimethylsilyl Derivatives in the Analysis of Serum
Amino Acids in Metabolic Diseases
H. J. Chaves das Neves* and A. M. P Vasconcelos
.
D epartamento de Quimica, Faculdade de Cigncias e Tecnologia, Universidade Nova de Lisboa, 2 825 M onte da Caparica, Portugal

J. Rueff Tavares and P. Nogueira Ramos
Faculdade de Ciencias Medicas, Universidade Nova de Lisboa, Campo deSantana, 1130 Lisboa Codex, Portugal

Key Words:
Gas chromatography, GC
Capillary column
Amino acids
Derivatization
Serum

I

I

Presented at the
Eighth ~ntern~tional
Symposium
on Capillary Chromatography

Summary

1 Introduction

Reaction of amino acids with N-methyl-N-(tert-butyldimethylsily1)trifluoroacetamide(MTBSTFA) in acetonitrile affords good
yields of amino acidderivatives with excellent gas chromatographic and mass spectrometric properties. The single-step
derivatization procedure is highly reproducible. The TBDMS
amino acids are stable at room temperature for at least three
days. Only a single peak is observed for each amino acid. The
procedure allows simultaneous analysis of asparagine and
glutamine together with other serum amino acids. Separationis
achievedon a borosilicate glass capillary coated with OV-1. The
mass spectra of the TBDMS amino acids possess characteristic
diagnostic ions. These properties were used in the sensitive
detection by GC-MSandSIM-GC-MSof GABA and pipecolic acid
in the serum of a newborn suspected of a Zellweger-type
syndrome, which could not be detected by other methods.

Some amino acids function asneurotransmitters or neuromodulators. Abnormal metabolic interactions involving
such amino acids might in some way be connected t o
neurological disfunctions. The role of y-aminobutyric acid
(GABA) and glycine as inhibitory transmitters in the central
nervous system is well established. Elevated serum
concentrations of pipecolic acid are a common feature
in neonatal adrenoleukodystrophy, Refsumdisease,
hyperpipecolic acidemia, and in the Zellweger syndrome
[ l]. Patients with the cerebro-hepato-renal Zellweger
syndrome seem to have a reduced ability to dispose of
pipecolic acid [ Z ] . Pipecolic acid is described as having an
inhibitory effect on the central nervous system, possibly

12

Journal o f H igh Resolution Chromatography & C hromatography Communications

0 1988 Dr.Alfred Huethig Publishers

Capillary GC of Amino Acids as tert-Butyldirnethylsilyl Derivatives

through inhibition of GABA reuptake [3]. Analytical
methods for pipecolic acid are in general too insensitive to
allow reliable analysis of pipecolic acid in biological
samples [4-101.A selected-ion monitoring method for pipecolic acid, proline, and GABA was recently reported [l1. In
1
this...