Analysis of Thin-Layer Chromatography Spots by Thermal Desorption/Fourier Transform Infrared Spectrometry

Abstract

A method is described for obtaining Fourier transform infrared (FT-IR) absorbance spectra of substances separated on silica gel thin-layer chromatographic (TLC) plates. The separated TLC spot is scraped off and loaded onto the sample pan of a thermogravimetric analyzer (TGA)/FT-IR. The FT-IR spectrum of the sample is obtained after the sample is thermally desorbed from the silica gel. Spectra are easily identified for samples present at level of 20 μg per TLC spot. A detection limit of 0.8 μg is reported for analysis of methyl benzoate. The total time required for sample preparation and thermal desorption/FT-IR analysis was six to seven minutes. The relationship between the spectrum peak intensity and the furnace heating rate was also studied. This method can be applied to thermally stable substances which can be desorbed from thermally stable TLC stationary phases.

Keywords

Infrared spectrometry Chromatography thin-layer Spectroscopic techniques

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References

Touchstone

J. C.

, J. Chromatogr. Sci. 26, 645 (1988).

Sherma

, Anal. Chem. 60, 74 (1988).

Percival

C. J.

and Griffiths

P. R

, Anal. Chem. 47, 154 (1975).

Gromez-Taylor

M. M.

and Griffiths

P. P

, Appl. Spectrosc. 31, 528 (1977).

Fuller

M. P.

and Griffiths

P. R

, Anal. Chem. 50, 1906 (1978).

Zuber

G. E.

Warren

R. J.

Begosh

P. P.

and O'Donnell

E. L

, Anal. Chem. 56, 2935 (1984).

Yeates

L. B. Lloyd. R. C.

and Eyring

E. M

, Anal. Chem. 54, 549 (1982).

White

R. L.

, Anal. Chem. 57, 1819 (1985).

Chalmers

J. M.

Mackenzie

M. W.

and Sharp

J. L

, Anal. Chem. 59, 415 (1987).

10.

Shafer

K. H.

Griffiths

P. R.

and Wang

S. Q

, Anal. Chem. 58, 2708 (1986).

11.

Low

M. J. D.

and Freeman

S. K

, Anal. Chem. 39, 194 (1967).

12.

Venema

A. J.

, High Resolut. Chromatogr. Chromatogr. Commun. 11, 843 (1988).

13.

Griffiths

P. R.

and De Haseth

J. A

, Fourier Transform Infrared Spectrometry (Wiley, New York, New York, 1986), Chap. 18, pp. 564–609.

14.

Cook

B. W.

and Cleary

, Analyst (London) 113, 1171 (1988).

15.

Avarraga

L. V.

and Hanna

D. A

, GIFTS, Athens ERL GC/FTIR Software and Users' Guide (U.S. EPA/ERL, Athens, Georgia, 1979).

16.

Ingle

J. D.

Jr. , and Crouch

S. R.

, Spectrochemical Analysis (Prentice Hall, Englewood Cliffs, New Jersey, 1988), Chap. 6, p. 173.