M.J. LeBelle

The Examination of Illicit Cocaine

A laboratory system of examination of illicit cocaine exhibits is described. Separation and identification of many of the components in exhibits are achieved by the use of capillary column gas chromatography and a Finnigan ion trap detector. Further examination and quantitation of the components of exhibits is achieved using two high performance liquid chromatographic (HPLC) systems. Both of these systems use identical reverse phase C8 columns. System 1 employs a solvent composed of 40% acetonitrile, 10% tetrahydrofuran and 50% 0.1% v/v aqueous triethylamine. The eluant is monitored at 280 nm. This system is preferred for routine quantitative analysis of cocaine and related alkaloids in exhibits. System 2 employs a solvent composed of 30% acetonitrile and 70% 0.05M phosphate buffer (pH = 5.0). The eluant from this system is monitored at both 220 and 280 nm. This system offers advantages in sensitivity. The relative retention times of a number of relevant substances as determined with gas chromatography and the two HPLC systems are given. The utility of the methodology for the identification and comparison of exhibits is demonstrated.

Comparison of Illicit Cocaine by Determination of Minor Components

High-performance liquid chromatography (HPLC) and gas chromatography (GC) combined with both a flame ionization detector (FID) and a mass spectrometer (MS) were used to determine the minor components in illicit uncut cocaine. Two HPLC systems were used to determine, in cocaine exhibits, the relative amounts of the main coca alkaloids: cocaine, cis-cinnamoylmethylecgonine (CIS), and trans-cinnamoyl-methylecgonine (TRANS). GC/FID and GC/MS were used to determine only the acidic and neutral components of cocaine exhibits. The significance of the presence of these minor components and their use to the forensic chemist for the matching and comparison of exhibits are discussed.

Identification and determination of norcocaine in illicit cocaine and coca leaves by gas chromatography-mass spectrometry and high-performance liquid chromatography

Routine gas chromatographic-mass spectrometric examination of illicit cocaine exhibits indicated the presence of norcocaine. Examination of coca leaves also demonstrated the presence of this alkaloid. Some illicit exhibits were also examined by high-performance liquid chromatography and were shown to contain more than 1% of norcocaine. No conclusions were possible regarding the source of this alkaloid.

Nuclear magnetic resonance identification and estimation of solvent residues in cocaine

Abstract Nuclear magnetic resonance spectroscopy was used to determine solvent residues in illicit cocaine exhibits. An internal standard was employed for the quantitative estimation of each of the five most common solvents found in exhibits: benzene, toluene, acetone, methyl ethyl ketone and ethyl ether. Methylene chloride and ethyl acetate also were detected in cocaine exhibits for the first time.

Isolation and identification of a fluorophore from ampicillin degradation.

A fluorescent impurity in ampicillin has been isolated and identified as 2‐hydroxy‐3‐phenyl‐pyrazine. The product is formed under acidic conditions similar to those employed in some fluorometric assay procedures. The mechanism of the reaction is proposed to involve cyclization by condensation of the penilloaldehyde of ampicillin. The structure was confirmed by independent synthesis.

High Performance Liquid Chromatographic Analysis of Rifampin and Related Impurities in Pharmaceutical Formulations

Abstract High pressure liquid chromatography was employed for the assay of rifampin in capsules. A reverse phase RP-2 column and a mobile phase of 48% methanol, 5% tetrahydrofuran and 47% 0.05 M ammonium formate (pH 7.3) were used with detection at 254 nm. Rifampin was separated from all its major degradation products and quantitated.

Nuclear Magnetic Resonance Identification of the Phenylalkylamine Alkaloids of Khat Using a Chiral Solvating Agent

Nuclear magnetic resonance was used for the identification of three major alkaloids in dried leaves of the khat plant, Catha edulis. Proton nuclear magnetic resonance spectra of plant extracts confirmed the presence of cathinone, norpseudoephedrine and norephedrine. The subsequent addition of a chiral solvating agent, (S)-(−)-1,1′-bi-2-naphthol, to these NMR solutions enabled the identification of the various enantiomers of these alkaloids. Both the (S)- and (R)- enantiomers of cathinone were detected. The results from the determination of the alkaloid ratios in the dried plant material by the NMR method are compared to those obtained by a previously developed gas chromatographic method.

High Performance Liquid Chromatographic Analysis of Penicillin V Solid Dosage Forms

Abstract An isocratic high performance liquid chromatographic (HPLC) method for the determination of Penicillin V in solid dosage forms is described. A reverse phase RP-8 column and a mobile phase of 52% methanol in 0.05 M phosphate buffer (pH 3.3) were employed. Detection was effected at 254 nm. The results obtained are compared with those from the iodometric method.

Gas chromatographic-mass spectrometric identification of chiral derivatives of the alkaloids of KHAT

Abstract The major alkaloids of the plant khat, Catha edulis , were conclusively identified by derivatization with ( R )-(+)-α-methoxy-α-(trifluoromethyl)phenylacetic acid. The acid was first reacted with dicyclohexyldicarbodiimide to give in situ the anhydride. The resulting amides formed from reaction with the anhydride were separated by gas chromatography. Separation characteristics of the derivatives of the alkaloids with other chiral acids and an anhydride are also given. Analysis of samples seized in Canada indicated large amounts of the enantiomer of cathinone, the alkaloid chiefly responsible for the activity of the plant. In some samples almost racemic mixtures of the two isomers were detected. These results indicate that racemization of the naturally occurring cathinone in the plant is an important process.

Identification of N-formylnorcocaine and N-benzoylnormethylecgonine in illicit cocaine

Gas chromatographic determination of the acidic and neutral components of illicit cocaine indicated the presence of one or more common components in different samples. Isolation and examination of the spectroscopic properties of the major impurity indicated it to be N-formylnorcocaine. The material was compared with authentic material synthesized from norcocaine. N-Benzoylnormethylecgonine was also found to be present in illicit cocaine.