Sample preparation for gas chromatography with electron capture detection: Determination of total and free thyroxin in serum

✍ Scribed by Eugene J. Rogers; Roger W. Giese

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 874 KB
• Volume: 164
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(87)90517-3

✦ Synopsis

Relatively clean gas chromatography with electron capture detection (GC-ECD) chromatograms are obtained for both total and free thyroxin (T4) in serum by improving sample preparation. This is based on establishing a sequence of steps that cumulatively overcome two classes of interference: those present in the initial sample and those introduced by the procedure. The main source for the latter contaminants is the derivatization step, a problem that was largely overcome by employing HPLC after this step. Also it is helpful to use ion-exchange columns early in the procedure under fast-flow conditions with intermediate flows of air to speed up and enhance their reliability. The work establishes some guidelines for future applications of GC-ECD to the determination of sub-nanogram analytes requiring derivatization, an area in which GC-ECD has been remiss in the past. As a side benefit, total T4 in serum is determined by HPLC for the first time with uv detection. 0 1987 Academic hes, IX.