Our new Rxi ® -1ms column, designed for GC-MS applications, provides the ultra-low bleed and exceptional inertness needed for analyzing urinary steroid hormones. For this application we derivatized six sex hormones, using methoxylamine HCl and trimethylsilyl imidazole to improve chromatography. Figure 1 shows this variety of derivatized steroid sex hormones, analyzed in less than 25 minutes by using an Rxi ® -1ms column. Note that these compounds elute at temperatures near or above 300°C and that bleed from the Rxi ® -1ms column is negligible at these temperatures. The Rxi ® -1ms column exhibits the inertness needed to produce Gaussian peaks and excellent resolution.