Improved gas chromatography/mass spectrometry analysis of barbiturates in urine using centrifuge-based solid-phase extraction, methylation, with d5-pentobarbital as internal standard.

Effective solid-phase extraction, derivatization, and GC/MS procedures are developed for the simultaneous determinations of butalbital, amobarbital, pentobarbital, and secobarbital, using a deuterated pentobarbital (d5-pentobarbital) as the internal standard. Buffered (pH 7) urine samples were extracted with Bond Elute Certify II cartridge. Iodomethane/tetramethylammonium hydroxide in dimethylsulfoxide was used for methylation, while a HP 5970 MSD equipped with a 13 m J & W DB-5 column (5% phenyl polysiloxane phase) and the Thru-Put Target software package were used for GC/MS analysis and data processing.

Monoclonal and polyclonal antibody responses to the myelin basic protein epitope present in human urine.

The myelin basic protein (MBP)-like material (MBPLM) in human urine is expressed in a cryptic epitope(s) present in MBP peptide 80-89 and absent or inaccessible in intact MBP. These features of urinary MBPLM have made it difficult to produce reagents for its further characterization. Using an immunogen of keyhole limpet hemocyanin conjugated to MBP peptide cys 74-89, polyclonal antiserum to urinary MBPLM was prepared.