Development of an assay for the extraction and quantification of nine 5-n-alkyl-5-ethyl barbituric acids in various rat tissues

Methods were developed to quantify a series of nine homologous 5-n-alkyl-5-ethyl barbituric acids in 15 rat tissues. Tissue homogenates were spiked with one of four multicomponent mixtures (methyl to n-propyl, n-propyl to n-pentyl, n-pentyl to n-heptyl and n-pentyl to n-nonyl). Liquid–liquid extraction was used to extract the homologues from the rat tissues. Reverse phase HPLC with UV detection at 214 nm was used to separate and quantify the individual barbiturates. The limit of detection for each respective homologue was 1 μg g^?1 except skin and bone (2 μg g^?1). The methodology developed reduced a potential 135 individual assays to a more manageable 16.