A Study of Illicit Cocaine Seizure Classification by Pattern Recognition Techniques Applied to Metal Data

Abstract

Fifteen metallic species, silver (Ag), aluminum (Al), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb), strontium (Sr) and zinc (Zn), were determined in 46 cocaine samples confiscated by the Spanish police in Galicia (northwest Spain). Classification of these cocaine samples according to their geographic origin (Colombia and Venezuela) was achieved by the application of pattern recognition techniques to the metallic content data. Cocaine samples, around 0.5 g, were directly dissolved in 2 mL of 35.0%(v/v) HNO3, diluted to 10 mL with ultrapure water. The metals were quantified by means of electrothermal atomic absorption spectrometry (Ag, Al, Cd, Cr, Cu, Mn, Ni, Pb and Sr), flame atomic absorption spectrometry (Ca, Fe, Mg and Zn), and flame atomic emission spectrometry (K and Na). Results show that two geographic origins can be established through the presence of trace and major elements.

Direct analysis of Antarctic krill by slurry sampling: determination of copper, iron, manganese and zinc by flame atomic absorption spectrometry

“…Nitric acid has been used by several authors [27][28][29] because the analytes are mobilized from the solid particles to the liquid media, which improves the precision of the method 7 , while nitrates do not interfere in the atomization paths for the metals involved. The concentrations selected, 2.0 mol L -1 for Cu, Fe and Zn and 4.0 mol L -1 for Mn, were used according to previous studies shown in Figure 1.…”

“…However, a number of factors must be considered to obtain an analytical performance comparable to that achieved with liquid sampling. The introduction of the sample as a slurry is an alternative that has been used to analyze a diversity of elements in different matrices [3][4][5][6][7][8] . Comprehensive reviews on this methodology have been reported in the literature 9,10 .…”

Investigating the Source of Contamination Opioid into Lead in Forensic Medicine

“…After separation of samples for preparation of samples for quantitative analysis, wet digestion method was used [9]. The 20 mg portion of the weighed sample was shaken up in a Chinese capsule with 2 ml of nitric acid (35% v/v) with a glass rod until complete digestion, and then the contents of the Chinese capsule were transferred to a 50 ml balloon and distilled water was added to the volume.…”

“…Drug overdose is one of the major causes of mortality from poisoning in our country [9][10][11][12]. Deaths from acute drug poisoning are important in many aspects of medicine, in particular forensic medicine.…”

Sinais de fundo em análise instrumental: uma discussão essencial em cursos de graduação

“…A comparação dos corretores Zeeman e D 2 para a compensação do BG na determinação de arsênio em água do mar por GFAAS, utilizando Pd(NO 3 ) 2 como modificador químico, demonstra essa eficácia. 12 Resultados exatos só foram obtidos com corretor Zeeman, que corrigiu efetivamente o BG causado por cloreto, sódio, potássio, cálcio e silício. Esse corretor também é o único capaz de corrigir BG estruturado, tal como aquele causado por fosfato sobre a determinação de Cd e Pb em baixos comprimentos de onda de absorção.…”