A rapid throughput octanol-water lipophilicity measurement based on 96-well shake-flask and LC/UV/APPI/MS is described. The method utilizes central liquid storage where compounds are stored as 10 mM solutions in dimethyl sulfoxide (DMSO). The DMSO is subsequently removed to generate solid like material used for LogD measurement. The removal of DMSO minimizes the concern for potential DMSO cosol...

Treatment of aldosterone with 35% HCl in EtOH or in MeOH followed by the picolinyl derivatization gave the picolinyl derivative of aldosterone-ethyl ether, 8, or methyl ether, 9, as a single and well-shaped liquid chromatographic peak. Picolinyl derivatization of aldosterone produced 21-picolinyl derivative of 18,20-anhydro-hemiacetal derivatives, 6, with poor chromatographic peak with wide hal...

We extend the quantal hypernetted-chain (QHNC) method, which has been proved to yield accurate results for liquid metals, to treat a partially ionized plasma. In a plasma, the electrons change from a quantum to a classical fluid gradually with increasing temperature; the QHNC method applied to the electron gas is in fact able to provide the electron-electron correlation at an arbitrary temperat...

Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the direct analysis of liquid samples. Several interesting results were found. First, in contrast to the previous DESI analysis of dried solid samples that was limited to proteins with MW < or = 25 kDa (Anal. Chem. 2007, 79, 3514), bovine serum albumin (BSA, 66 kDa) was successfully ionized from solutions by DESI w...

We present a fatal case involving the combined ingestion of amphetamine, 3,4-methylenedioxymethylamphetamine, 3,4-methylenedioxyamphetamine, and paramethoxyamphetamine. Various postmortem specimens (e.g., several blood samples, urine, and tissue samples) were analyzed to study the distribution of the compounds and their metabolites in the human body. Quantitation took place using liquid chromat...

BACKGROUND Matrix effects can profoundly reduce the performance of electrospray ionization mass spectrometry. Preliminary observations indicated that the methanol used in the mobile phase could be a source of differential ionization or ion suppression. METHODS Drug stability studies, analysis of biological extracts, mixing experiments, and postcolumn infusions were used to test 9 commercial m...