The recovery of alkaloids after their location on thin layer chromatograms.

A method was developed for the recovery of 29 alkaloids from TLC plates after they had been complexed with either potassium iodoplatinate (for tertiary amines) or carbon disulphide (for primary and secondary amines). A comparison was made between the percentage recoveries of these alkaloids from 5 different types of TLC plate. In addition, the stability of these alkaloids on TLC plates over a 7 day period was studied. Assays were, where possible, carried out by UV spectrophotometry but gas chromatography was used for alkaloids which possessed low UV absorbtivity values. All the alkaloids extracted from TLC plates were examined by low resolution mass spectrometry.

High-performance liquid chromatography systems for the analysis of analgesic and non-steroidal anti-inflammatory drugs in forensic toxicology.

High-performance liquid chromatography retention data are presented for over 40 analgesic drugs on an ODS-silica packing material to assist in the identification of these compounds. Three isocratic eluents prepared from isopropanol, formic acid and an aqueous phosphate buffer have been used. One eluent has been used for the analysis of paracetamol in whole blood.

The recovery and identification of fluoroacetamide and fluoroacetic acid from tissues.

A rapid method is described for the extraction and identification of fluoroacetamide and fluoroacetic acid from tissues, by gas chromatography, using a mass spectrometer in the multiple ion monitoring mode as the detector. Recoveries from animal and human tissue macerates, after the addition of each compound, were approximately 30--35% for fluoroacetamide and 50--55% for fluoroacetic acid. Minimum detectable levels in tissues were found to be circa 0.7 mug/g for the amide and 0.1 mug/g for the acid. Visceral tissue levels were found to be approximately 3 mug/g for fluoroacetamide, and 2.5--10 mug/g fluoroacetic acid in guinea pigs and rabbits which had been fatally poisoned with these compounds.

The decomposition of benzodiazepines during analysis by capillary gas chromatography/mass spectrometry.

A capillary gas chromatography column directly interfaced to a mass spectrometer was used for the analysis of sixteen benzodiazepines. The thermal stability of the drugs was found to be related to their chemical structure. Nine of the benzodiazepines were thermally unstable indicating that care should be taken in the interpretation of gas chromatographic data from this class of drugs. The unstable benzodiazepines were: ketazolam which decomposes to diazepam; N-4 oxides (chlordiazepoxide and demoxepam) which lose an oxygen radical; aromatic 7-nitro compounds (nitrazepam and clonazepam) which are partially reduced to the corresponding amine; alpha-hydroxy ketones (lorazepam and oxazepam) which decompose with the loss of water and N-methyl-alpha-hydroxy ketones (lormetazepam and temazepam) which partially decompose with the loss of a hydrogen molecule to produce the corresponding alpha, beta-diketones. Few problems were encountered in distinguishing the drugs by their mass spectra, the exceptions being ketazolam which decomposes to diazepam and demoxepam which decomposes to desmethyldiazepam. In general, good spectra were obtained from 20-50 ng of drug injected. However, for those compounds where the decompositions were not quantitative (nitrazepam, clonazepam, lormetazepam, temazepam) detection limits were poor.