4 results match your criteria coelutes isomer

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Spotting isomer mixtures in forensic illicit drug casework with GC-VUV using automated coelution detection and spectral deconvolution.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 Mar 29;1173:122675. Epub 2021 Mar 29.

Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, Amsterdam 1090 GD, the Netherlands; Co van Ledden Hulsebosch Center (CLHC), Amsterdam Center for Forensic Science and Medicine, PO Box 94157, Amsterdam 1090 GD, the Netherlands.

Analysis of isomeric mixtures is a significant analytical challenge. In the forensic field, for example, over 1000 new psychoactive substances (NPSs), comprising of many closely related and often isomeric varieties, entered the drugs-of-abuse market within the last decade. Unambiguous identification of the isomeric form requires advanced spectroscopic techniques, such as GC-Vacuum Ultraviolet Spectroscopy (GC-VUV). Read More

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Gas chromatographic optimization studies on the side chain and ring regioisomers of methylenedioxymethamphetamine.

J Chromatogr Sci 2004 Jul;42(6):293-8

Department of Pharmacal Sciences, School of Pharmacy, Auburn University, Auburn, AL 36849, USA.

Gas chromatographic (GC) optimization studies are conducted for the 10 methylenedioxyphenethylamine regioisomeric substances related to the drug of abuse 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy). These 10 compounds, having the same molecular weight and equivalent major mass spectral fragments, are not completely resolved using typical GC-mass spectrometry screening methods for illicit drugs. MDMA coelutes with at least one nondrug regioisomer under standard drug screening conditions. Read More

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Identification of a second active site residue in Escherichia coli L-threonine dehydrogenase: methylation of histidine-90 with methyl p-nitrobenzenesulfonate.

Arch Biochem Biophys 1995 Jan;316(1):413-20

Department of Biological Chemistry, University of Michigan, Ann Arbor 48109-0606.

Incubation of L-threonine dehydrogenase from Escherichia coli with methyl p-nitrobenzenesulfonate results in a time- and concentration-dependent loss of enzymatic activity. As the concentration of the methylating agent is increased, the rate of inactivation reaches a limiting value of 0.01 min-1 at pH 7. Read More

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January 1995

Mirex: an unrecognized contaminant of fishes from Lake Ontario.

K L Kaiser

Science 1974 Aug;185(4150):523-5

A perchlorinated, cage-structured hydrocarbon, C(10)C(l2), also known as mirex or Dechlorane, has been identified in fish samples from the Bay of Quinte, Lake Ontario, Canada. The compound coelutes with polychlorinated biphenyls (PCB's) in residue cleanup procedures and under standard gas chromatographic conditions. Mirex has never been registered for use as an insecticide in Canada, nor does it appear to be in use in any area of the United States discharging water into Lake Ontario or its tributaries. Read More

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