Clinical applications of gas chromatograph/mass spectrometer/computer systems.

Evaluation of a benchtop capillary gas chromatograph-mass spectrometer for clinical toxicology.

We evaluated the Hewlett-Packard 5995B benchtop capillary gas chromatograph-mass spectrometer (GC-MS) for its ability to identify drugs commonly detected and (or) measured in the clinical toxicology laboratory. Initial experiments indicated that the instrument as originally configured, with an isolation valve between the gas chromatograph and mass spectrometer, was unsatisfactory for the identi...

Derivatization in mass spectrometry --7. On-line derivatisation/degradation.

The review describes on-line derivatization/degradation methods employed in mass spectrometry to solve some structural and analytical problems. Advantages and applications of various positions of reaction systems connected mainly to a mass spectrometer or a gas chromatograph/mass spectrometer are considered. Among these are reaction systems connected directly to the mass spectrometer (reaction ...

Volatile carboxylic acid profiling in physiological fluids: direct injection into a gas chromatograph/mass spectrometer.

We present a procedure for the profiling of the volatile carboxylic acids and neutral compounds in blood or urine using the direct injection of the acidified sample into a gas chromatograph interfaced with a mass spectrometer by a jet separator. The non-volatile components remain at the head of the SP-1000 column while the volatile components move through the column. Up to sixty physiological s...

Flexible data handling for routine quantitative analyses employing a gas chromatograph-mass spectrometer under computer control

Methylene unit calibration for analysis of organic acids by gas--liquid chromatography/mass spectrometry.

We describe a method for automatic computation of "methylene unit" retention-time indices in real time on a computer-controlled gas chromatograph/mass spectrometer system. The calculation is based on the exponential relationship between the methylene unit values of hydrocarbon reference standards and the oven temperature at their elution. Using this mathematical relationship, we calculated cali...