Robert F. X. Klein

Recent advances by the U.S. Drug Enforcement Administration in drug signature and comparative analysis

Abstract A general review of comparative analyses of illicit drug substances is presented, including discussion of both trace level chemical and ballistics examinations. The results are important for deriving strategic and tactical intelligence via forensic analysis.

Determination and in-depth chromatographic analyses of alkaloids in South American and greenhouse-cultivated coca leaves

Methodology is described for the detection and/or determination of cocaine and minor alkaloids in South American coca as well as in greenhouse- and tropical-cultivated field coca of known taxonomy. Coca leaf from Bolivia, Peru, Ecuador and Colombia were subjected to the determination of cocaine, cis- and trans-cinnamoylcocaine, tropacocaine, hygrine, cuscohygrine and the isomeric truxillines. The greenhouse samples were cocaine-bearing leaves of the genus Erythroxylum and included E. coca var. coca, E. novogranatense var. novogranatense and E. novogranatense var. truxillense, and the alkaloids determined were cocaine, ecgonine methyl ester, cuscohygrine, tropacocaine and the cinnamoylcocaines. The tropical-cultivated coca were E. novogranatense var. novogranatense and E. coca var. coca. Cocaine and minor alkaloids were isolated from basified powdered leaf samples using a toluene extractant, followed by acid-Celite column chromatography. The isolated alkaloids were determined by capillary gas chromatography with flame ionization or electron-capture detection. Methodology is also presented for the isolation and mass spectral analysis of numerous trace-level coca alkaloids of unknown structure.

High-performance liquid chromatographic analysis of benzodiazepines using diode array, electrochemical and thermospray mass spectrometric detection

Abstract Twenty benzodiazepines were examined via a combination of high-performance liquid chromatography (HPLC)-diode array-dual electrochemical detection and HPLC-thermospray mass spectrometric detection. Although UV detection at 230 nm resulted in extensive overlap of the benzodiazepines, each compound gave unique UV spectra. Twenty percent of the benzodiazepines tested gave response ratios via oxidation detection, and the values obtained were unique. All compounds except chlorazepate gave MH + ions as the base peak via thermospray-mass spectrometric detection with filament off; additional ions were detected for many compounds. Using single ion chromatograms all benzodiazepines can be chromatographically resolved.

Synthesis and Characterization of the 2,3-Methylenedioxyamphetamines

Synthetic methods and spectroscopic and chromatographic data are provided for four 2,3-methylenedioxyamphetamines (2,3-MDA, N-methyl-2,3-MDA, N-ethyl-2,3-MDA and N,N-dimethyl-2,3-MDA). These compounds are aromatic positional isomers of the corresponding 3,4-methylenedioxyamphetamines, which are well known, widely abused central nervous system stimulants with euphoric properties. Direct spectroscopic and chromatographic comparisons of the two isomeric series indicate that the 2,3-MDAs may be easily and unambiguously differentiated from the corresponding 3,4-MDAs via standard analytical methodologies.

The Stereoisomers of 4-Methylaminorex

Physical constants and instrumental data (melting point [mp], thin-layer chromatography [TLC] [Rf], gas chromatography [GC] [Rt], [ α ] D 25 , 1H- and 13C-nuclear magnetic resonance [NMR], infrared (IR), 70-eV, electron impact-mass spectroscopy [EI-MS], color, and microcrystalline tests) are reported for the individual stereoisomers, racemates, and corresponding hydrochloride salts of 4-methylaminorex (2-amino-4-methyl-5-phenyl-Δ2-oxazoline, 4,5-dihydro-4-methyl-5-phenyl-2-oxazolamine, McN-822, “U4Euh,” “ICE”). The data allow identification and differentiation of illicit samples of 4-methylaminorex.

Sensitive detection of nicotine after its novel perfluoroacylation and analysis using capillary gas chromatography-electron-capture detection

Abstract The on-column chromatographic detection of nicotine at low picogram levels is described. Nicotine is first subjected to chemical derivatization with heptafluorobutyric anhydride in the presence of pyridine. In the absence of pyridine, the derivatization reaction is markedly retarded. This high-yield reaction results in the opening of the N-methylpyrrolidine ring of nicotine with concomitant formation of a highly electrophilic N,O-diheptafluorobutyryl derivative. After extraction of the nicotine derivative into isooctane, it is subjected to splitless capillary gas chromatographic analysis using a 63 Ni electron-capture detector and a moderately polar fused-silica capillary column. The nicotine derivative can be detected on-column at levels below 5 pg.

The effects of microwave irradiation on occluded solvents in illicitly produced cocaine hydrochloride

The current clandestine methodology for the manufacture of illicit cocaine hydrochloride utilizes microwave heating in order to dry the finished product. This study addresses the effects this step has on the occluded solvents present in newly prepared cocaine hydrochloride. Nine 1-kilogram-sized batches of cocaine hydrochloride were prepared from cocaine base using a variety of solvents or solvent mixtures commonly utilized in clandestine laboratories, pressed into bricks, and submitted to microwave heating. Residual solvents were qualitatively and quantitatively monitored before, during, and following the microwaving step by static headspace-gas chromatography-mass spectrometry. All solvents used in the conversion process were easily detected in the bricks even after extensive irradiation, confirming that occluded solvents are extremely resistant to removal by microwave heating. Qualitative and quantitative data corresponding to the residual solvents in the prepared cocaine hydrochloride bricks are presented.

Hygrine, bona fide alkaloid or artifact: its chemical reduction, novel di-heptafluorobutyrylation and sensitive detection in South American coca leaves using capillary gas chromatography-electron capture detection

Methodology is described for the isolation of hygrine, along with the related compound-cuscohygrine, from South Americancoca leaf and its major tropane alkaloids. The isolated hygrine was reduced with lithium aluminum hydride to yield diastereomeric alcohols, which were subsequently derivatized with heptafluorobutyric anhydride in the presence of 4-dimethylaminopyridine. The resultant diastereomeric di-heptafluorobutyryl derivatives could be detected on-column at femtogram levels when using a polar fused-silica capillary column interfaced with 63Ni electron-capture detector. The artifactual formation of hygrine, resulting from the degradation of cuscohygrine, is discussed. Quantitative data are provided for hygrine and cuscohygrine levels in South American coca.