RH Liu

Simultaneous Analysis of Amphetamine, Methamphetamine, and 3,4-Methylenedioxymethamphetamine (MDMA) in Urine Samples by Solid-Phase Extraction, Derivatization, and Gas Chromatography/Mass Spectrometry

Daniel Baugh, RH Liu, AS Walia · Journal of Forensic Sciences · 1991 · 54 citations

Solid-phase Extraction, Chemistry, Derivatized Amphetamine +22

Improved Gas Chromatography/Mass Spectrometry Analysis of Barbiturates in Urine Using Centrifuge-Based Solid-Phase Extraction, Methylation, with d5-Pentobarbital as Internal Standard

RH Liu, AM McKeehan, C Edwards et al. · Journal of Forensic Sciences · 1994 · 51 citations

Gc/ms Procedures, Chemistry, Separation Science +20

Selecting an Appropriate Isotopic Internal Standard for Gas Chromatography/Mass Spectrometry Analysis of Drugs of Abuse—Pentobarbital Example

RH Liu, Gregory H. Foster, E. J. Cone · Journal of Forensic Sciences · 1995 · 46 citations

Forensic Chemistry, Gas Chromatography, Drug Purity +23

Isotopic Analogue as the Internal Standard for Quantitative Determination of Benzoylecgonine: Concerns with Isotopic Purity and Concentration Level

RH Liu, LD Baugh, E Ellen Allen et al. · Journal of Forensic Sciences · 1989 · 16 citations

Engineering, Concentration Level, Isotopic Purity +20

Simultaneous Gas Chromatography/Mass Spectrometry Assay of Methadone and 2-Ethyl-1, 5-Dimethyl-3,3-Diphenylpyrrolidine (EDDP) in Urine

LD Baugh, RH Liu, AS Walia · Journal of Forensic Sciences · 1991 · 14 citations

Efficient Extraction, Medicine, Drug Discovery +15