Improved Extraction and LC/MS/MS Analysis of Barbiturates from Urine Samples

In this application note from Phenomenex, a fast and simplified SPE procedure, with Strata-X-Drug N, is used to concentrate and clean 5 barbiturates from urine samples prior to LC/MS/MS analysis. Barbiturate extraction methods on both Strata-X-Drug N and a traditional mixed-mode silica-based SPE sorbent are compared. After cleanup, resolution and separation were achieved with a Kinetex 2.6 μm C18 core-shell HPLC/UHPLC column for 5 barbiturate analytes, including resolution between pentobarbital and amobarbital which have been historically difficult to separate because they are structural isomers.