Investigation into the suitability of capillary tubes for microcrystalline testing

Leonie E. Elie*, Mark G. Baron, Ruth S. Croxton, Mathieu P. Elie

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

A comparison between microcrystalline tests performed on microscope slides and flat capillary tubes with inner diameters ranging from 0.1 to 0.7 mm was carried out to explore the appropriateness of tubes for rapid testing of suspected drugs of abuse in the laboratory as well as in the field. Tests for mephedrone, cocaine, and phencyclidine were chosen as examples to investigate the handling of the capillary tubes, the influence on crystal habit, size, and the effects on the limit of detection. Image stacking software was used to increase the depth of field of micrographs taken from developed microcrystals greatly enhancing the interpretability even months after carrying out the microcrystalline test. Additionally, the potential of seeding capillary tubes with a reagent was studied. Pre-treatment of tubes would allow microcrystalline tests to be carried out quicker and anywhere without the necessity of taking along expensive and hazardous reagents. The sealing of capillary tubes containing developed microcrystalline tests in order to preserve results for a long period of time was successfully done by applying paraffin wax to the open ends. Finally, it was concluded that capillary tubes are suitable vessels for performing microcrystalline tests. The increased portability of the improved set-up allows tests to be safely executed outside laboratories without impairing the quality of the result. Findings were applied to six legal high samples purchased online between May and August 2011. The active ingredients like MDAI as well as cutting agents like caffeine were successfully identified using the microcrystalline test technique in capillary tubes.

Original languageEnglish
Pages (from-to)573-580
Number of pages8
JournalDrug Testing and Analysis
Volume5
Issue number7
Early online date27 May 2012
DOIs
Publication statusPublished - 1 Jul 2013
Externally publishedYes

Keywords

  • Flat capillary tubes
  • Forensic confirmation test
  • Forensic drug analysis
  • Microcrystalline test
  • Novel psychoactive substances
  • Preservation of evidence
  • Software-based image combining

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