Evaluation of "Dexsil 300 GC" as stationary phase in gas chromatography of triiodothyronine and thyroxine in human serum.

We have evaluated the use of “Dexsil 300 GC,” a polycarboranesioxane, as the stationary phase in the GC measurement of N,O-dipivalyl methyl esters of pure T3 and T4, and T3 from human serum.2 Unlike other stationary phases,Dexsil 300 GC is stable up to 500#{176}C, which greatlyminimizes background caused by column bleed (1). Excellentseparationsand detectionofT3 and T4 were obtained at a column temperature of 305#{176}C and with use of an electron-capture detector.