Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
39, Number 10, October 2001, pp.
Preparation and Characterization of 3-(Aza-18-Crown-6) Propylsilyl
Bonded Phase for Reversed-Phase Liquid Chromatography
Shi-Lu Da, Yu-Qi Feng, Hui-Ning Da, Yin-Han Gong, and
Yuan-Wei Zhang
39,
Number 5, May 2001, pp. 195-199
Method for the Analysis
of Thyreostats in Meat Tissue Using Gas Chromatography with Nitrogen Phosphorus
Detection and Tandem Mass Spectrometric Confirmation John W. Pensabene, Steven J. Lehotay*, and Walter Fiddler
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional
Research Center, 600 East Mermaid Lane,
Wyndmoor, PA 19038
An
analytical method not requiring a mercury column cleanup step is described for
the isolation and detection of four thyreostatic agents in meat tissue. The
use of these growth promotants in livestock has been banned by regulatory agencies.
The meat tissue is homogenized with acetonitrile–water, centrifuged, and
the supernatant is partitioned with petroleum ether. The acetonitrile–water
is concentrated and then passed through a silica-gel column. The solvent is
then removed and the residue derivatized with N-methyl-N-(trimethylsilyl)-trifluoroacetamide.
The total amount of organic solvent used for the analysis is merely 35 mL. The
derivatized thyreostats are detected and quantitated by gas chromatography (GC)
equipped with a nitrogen–phosphorus detector. Percent recoveries from fortified
meat tissue (n = 6) at the 0.1-µg/g (parts per million) level are 93.5
± 2.9 for 2-thiouracil, 90.3 ± 3.0 for tapazole, 87.5 ±
2.9 for 6-methyl-2-thiouracil, and 85.1 ± 5.8 for 6-n-propyl-2-thiouracil.
For the confirmation of analyte identities, GC–tandem mass spectrometry
with an ion-trap instrument is used. The estimated minimum level for a reliable
measurement is 0.050 µg/g in meat tissue.
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