Determination of L-thyroxine in reference serum preparations as the o-phthalaldehyde-N-acetylcysteine derivative by reversed-phase liquid chromatography with electrochemical detection.
A simple procedure for the assay of L-thyroxine in serum preparations with D-thyroxine as internal standard is described. The L-thyroxine is extracted with acetonitrile, fractionated on a reversed-phase silica cartridge and analysed by reversed-phase high-performance liquid chromatography of the o-phthalaldehyde-N-acetyl-L-cysteine derivative. This derivative is not fluorescent, but may be detected with suitable sensitivity and selectivity with an electrochemical detector.
Lovell
G
G
National Institute for Biological Standards and Control, South Mimms, Hertfordshire, U.K.
Corran
P H
PH
D000111:Acetylcysteine; D000447:Aldehydes; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D015394:Molecular Structure; D011863:Radioimmunoassay; D013974:Thyroxine / Q000097:blood*; D009764:o-Phthalaldehyde
D000447:Aldehydes; D009764:o-Phthalaldehyde; D013974:Thyroxine; D000111:Acetylcysteine