A contribution to the improvement of accuracy in the quantitation of THC.

The accuracy of a quantitative analysis is highly dependent on the quality of the reference standard. Although reference standards are more and more supplied with a certificate, laboratories may feel the need for additional acceptance testing. In general, confirmation of the purity of many solid reference substances can be obtained by a number of simple tests. However, verification of the true content of reference solutions may be complicated. A number of problems with the THC quantitation caused our interest for a verification method for the THC reference solution. The quantitation of THC is performed by gas chromatography with flame ionisation detector. The effective carbon number concept was used to predict GC/FID response factors. Equations and data are presented to calculate theoretical response ratios of cannabinoids. The experimental data for CBD and CBN were in excellent agreement with the theoretical ones. The paper shows that the response factors of CBD and/or CBN can be used for the calculation of the THC content of either reference solutions or cannabis samples.

1-phenylethylamines: a new series of illicit drugs?

Since 1993 many seizures of 1-phenylethylamine have been made in several European countries. It was originally thought that 1-phenylethylamine had been made in error, but later information suggested that it had been prepared deliberately. The related compounds, 1-amino-1-(4-methylphenyl)ethane and 1-methylamino-1-phenylethane and the 1-propanamine isomer of 3,4-methylenedioxyamphetamine, have also occurred in isolated cases. Analytical data are presented on these amines as well as a number of Leuckart impurities in 1-phenylethylamine. The pharmacological effects of these substances are largely unknown.

Heroin impurity profiling. A harmonization study for retrospective comparisons.

Three laboratories present a harmonised system for the retrospective comparison of south west Asian heroin. It consists of an improved gas chromatographic (GC) profiling method and a computerised data retrieval. The investigations of the GC were necessary with a view to improve the reproducibility of the system. The necessity of a strict quality control is emphasized. The peaks of the GC profile were investigated for abundance, intensity, GC behaviour (reproducibility) and correlations; 16 of them were selected for describing the heroin profile in the database. The results from intra-lab profile comparisons are reported. The reproducibility of the analysis was good and the variation between the samples was large, thus, allowing conclusions with a high degree of certainty. The criteria of similarity were defined. The system is successfully running in all three labs. In connection with inter-laboratory comparison, the aspects of method harmonisation and standardisation are discussed. It appeared that the GC method is a very subtile one, urging for a strict standardisation between the three labs. Despite a long cooperation between three well-equipped and experienced labs, a more or less serious loss of reproducibility was noticed in the inter-lab results in comparison with the intra-lab results. The loss could for the greater part be attributed to the (limits of the) GC technique; a number of compounds, necessary for making the discrimination between samples, showed difficult chromatographic behaviour, leading to insufficient inter-lab reproducibility. Using the actual variables, improvements in performance can hardly be expected in the near future. The loss of reproducibilty implies that the number of false positive matches in a database search increases. This may strongly reduce the value of a relatively large, international database. The study shows that so far, the best option for international comparison is the analysis in a central laboratory. The idea of local determination at a large number of national labs and the use of a common database is not a realistic aim for this type of analysis.

Analytical studies on illicit heroin. II. Comparison of samples.

A rapid method for the comparative analysis of illicit heroin samples has been developed. It is based on high pressure liquid chromatography using an ultraviolet and a fluorimetric detector simultaneously. The two detectors give so much information that reliable conclusions can be made.

Analytical studies on illicit heroin. I. The occurrence of O3-monoacetylmorphine.

A thin-layer chromatographic method and a high pressure liquid chromatographic method have been developed for the analysis of O3-monoacetylmorphine in illicit heroin samples. The possible formation of O3-monoacetylmorphine during the production process of heroin and during its hydrolysis were also studied using these methods.

Residual solvents in methylenedioxymethamphetamine tablets as a source of strategic information and as a tool for comparative analysis: the development and application of a static headspace gas chromatography/mass spectrometry method.

Various solvents can be used in the synthesis of the illicit synthetic drug methylenedioxymethamphetamine (MDMA, commonly known as Ecstasy). In the crystallization process, traces of those solvents can be trapped inside crystals; during the following tabletting process, the solvent traces remain present in the tablets. The forensic investigation of tablets for solvents may increase knowledge of production methods and contribute to a possible choice of monitoring or regulating certain organic solvents. Further, the identification and quantification of solvents in MDMA tablets may contribute to the chemical characterization of illicit tablets for comparative examination. The methods of analysis of volatile components in illicit MDMA tablets described so far are often based on solid-phase micro extraction (SPME). To avoid several disadvantages of SPME, a quantitative static headspace method was developed using gas chromatography/mass spectrometry (GC/MS); for quantification, the standard addition method appeared to be advantageous. The residual solvents in 155 MDMA tablets were analysed and 150 of them were quantified.

Analytical studies on illicit heroin. V. Efficacy of volatilization during heroin smoking.

The recovery of heroin in fumes was investigated. In the Netherlands the common mode of heroin smoking is the 'chasing the dragon' procedure: heroin is heated on an aluminium foil by a lighter and the fumes are inhaled. The efficiency of the volatilization of heroin using this procedure was studied under laboratory conditions using thin layer chromatography, gas chromatography and high pressure liquid chromatography. A considerable influence of the form (salt or base) of the heroin was found as well as strong influences of other substances that may be present in illicit heroin samples as diluents. The danger of the inhalation of fumes containing unknown pyrolysis products is mentioned and a hypothesis is given for the phenomenon of 'heroin'-leucoencephalopathy that was observed in heroin smokers in Amsterdam in 1981. The types of heroin encountered in the Netherlands are discussed with regard to their suitability for smoking.

Analytical studies on illicit heroin. III. Auto-interference in the colorimetric determination of strychnine in illicit heroin samples.

The colorimetric determination of strychnine in illicit heroin samples, based on the reduction of strychnine followed by colour development with nitrite was checked. Interference by heroin was observed, as well as a strong interference by caffeine. It was concluded that results, based on this method, are not reliable.

Heroin in the Netherlands.

All heroin samples seized in the Netherlands in 1975 and weighing more than 10 grams together with all heroin samples seized during September 1976 were analysed by thin-layer chromatography, gas-liquid chromatography and liquid-solid chromatography. Most samples consisted of the so-called Hong Kong No. 3 type. Also the samples found in addicts were as potent as those seized from dealers and traffickers. We attempted to classify the samples into groups or batches, but only in a few cases could we conclude that two or more samples originated from the same batch.

Separation and identification of illicit heroin samples by liquid chromatography using an alumina and C18 coupled column system and photodiode array detection.

The analysis of illicit heroin and opium samples on a coupled alumina and C18 column system is described. The compounds to be analysed can be divided into two groups: those with low pKa values, such as caffeine, papaverine and noscapine, and those with high pKa values, such as heroin, acetylcodeine, O6-monoacetylmorphine, procaine, codeine, morphine and strychnine. The first group can best be separated on a C18 column, whereas alumina is more suitable for the second group. Previously reported criteria for choosing proper buffer systems for ion-exchange separations on alumina were used together with an iterative regressive optimization procedure developed in our laboratory. The system can be used with and without valve-switching, depending on the sample type. The peak purity of the judicially important components heroin and O6-monoacetylmorphine has been checked with a photodiode array detector and by use of advanced software.