PubMed Health⌕ Search

Biomedical subjects

Minemasa Hida

Publications and source records attributed to Minemasa Hida.

4 recordsLinked to original sources
PubMed2004

Rapid and sensitive determination of morphine in street opium samples by thermal desorption gas chromatography using a microfurnace pyrolyzer.

Thermal desorption of the alkaloids in opium samples at 300 degrees C using a vertical microfurnace pyrolyzer was followed by their on-line gas chromatographic (GC) analysis on a large-bore glass capillary column. This method permitted rapid and sensitive determination of the content of the main alkaloid, morphine, in the small (ca. 100 microg) opium samples with a relative standard deviation within 4% for 5 runs. The observed morphine contents of about 12 to 15 w/w% in the given opium samples were in fairly good agreement with those estimated by a conventional GC-MS method.

Alkaloids↗
PubMed2002

Analysis of dimethylamphetamine and its metabolites in human urine by liquid chromatography-electrospray ionization-mass spectrometry with direct sample injection.

An analytical method to identify and determine dimethylamphetamine (DMA) and its metabolites in human urine was developed with liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) involving the direct injection of a urine sample. The urine samples were directly injected by using a gel permeation column, whose stationary phase was polyvinyl alcohol with a small amount of a carboxyl group, so DMA and its metabolites were analyzed rapidly and simply without pretreatment such as extraction, concentration and derivatization. DMA and its metabolites were identified in drug-free human urine spiked with 1 microg of DMA, dimethylamphetamine N-oxide (DMANO) and methamphetamine (MA), and 3 microg of amphetamine (AM) in 1 ml of urine under the full-scan mode. Under the selected ion monitoring (SIM) mode, the limits of detection (signal-to-noise ratio=5) for DMA, DMANO, MA and AM were 20, 20, 20 and 60 ng in 1 ml of urine, respectively. This method was applied to the identification and determination of DMA and its metabolites in urine samples of 10 DMA abusers. The concentrations of DMANO were higher than those of unchanged DMA in all urine samples; thus, DMANO is considered to be a useful metabolite as an indicator to prove DMA intake.

Adolescent↗
PubMedDate not supplied

Analysis of pyrolysis products of methamphetamine.

This study examined the pyrolysis products of d-methamphetamine (d-MA) and the pyrolysis mechanism. A sealed glass tube, in which MA-HCl was placed, was wrapped with pyrolysis-foil and heated at the Curie point of the pyrolysis-foil. The pyrolysis products of MA were detected by gas chromatography-mass spectrometry and liquid chromatography-electrospray ionization-mass spectrometry. MA-d(3)-HCl, in which all the hydrogen atoms of N-methyl group of MA were substituted with deuterium atoms, was pyrolyzed to investigate the transformation of a methyl group of MA. Amphetamine (AM) and dimethylamphetamine (DMA) were produced via demethylation and methylation reactions, respectively, at temperatures above 315 degrees C. The demethylation and methylation reactions were the major pyrolysis processes at temperatures below 358 degrees C. At temperatures above 315 degrees C, the reaction of DMA with a methyl group eliminated from the methylamino group of MA resulted in the formation of benzylethyltrimethylammonium (BEMA). This transformation reveals that demethylation and methylation reactions occur in the form of a methyl cation. The thermal degradation of BEMA, the abstraction of a proton at the beta-position and the elimination of a trimethylamine, produced allylbenzene, cis-beta-methylstyrene, and trans-beta-methylstyrene at temperatures above 315 degrees C. At temperatures above 445 degrees C, the optical isomers, or l-isomers of AM, MA, and DMA, were produced as pyrolysis products.

Central Nervous System Stimulants↗