MilliporeSigma
  • Home
  • Search Results
  • Hydrogen peroxide reactions on cocaine in hair using imaging mass spectrometry.

Hydrogen peroxide reactions on cocaine in hair using imaging mass spectrometry.

Forensic science international (2014-07-23)
Eva Cuypers, Bryn Flinders, Ingrid J Bosman, Klaas J Lusthof, Arian C Van Asten, Jan Tytgat, Ron M A Heeren
ABSTRACT

Today, forensic hair analysis is considered to be a standard method for identifying chronic drug users since information about drug use stored and located in hair can cover several months to even years. When interpreting these results, one should be aware of all kind of pitfalls. External factors such as bleaching might influence the analytical result. Although the effect of hydrogen peroxide on cocaine in a solution was described before, it was never investigated whether the described reaction products (ecgonine methylester, benzoylecgonine, hydroxynorcocaine and dihydroxycocaine) are indeed found on contaminated or user hair. Since it is of great importance in forensic hair analysis to know whether cocaine and/or reaction products are detectable in hair after bleaching, matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) was used to study the effect of hydrogen peroxide treatment on incorporated cocaine in hairs. Cocaine oxidation products were identified in a solution based on MS/MS spectra and spatial distribution of these products in hair was explored using MALDI TOF-MS. All images were accomplished by spraying α-Cyano-4-hydroxycinnamic acid (CHCA) as a MALDI-matrix. Images revealed a loss of detectability of cocaine and its reaction products in hairs already after a short bleaching period. Since all compounds of interest are found in the hydrogen peroxide and wash solution, these findings indicate that all evidence of cocaine use might be lost after a hair bleaching treatment. Therefore, forensic toxicologists should take into consideration whether hair samples were bleached before making any conclusions from hair analysis results.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hydrogen peroxide solution, 30 % (w/w) in H2O, contains stabilizer
Sigma-Aldrich
Hydrogen peroxide solution, tested according to Ph. Eur.
Millipore
Hydrogen peroxide solution, 3%, suitable for microbiology
Sigma-Aldrich
Hydrogen peroxide solution, 34.5-36.5%
Sigma-Aldrich
Hydrogen peroxide solution, contains potassium stannate as inhibitor, 30-32 wt. % in water, semiconductor grade, 99.999% trace metals basis
Supelco
Hydrogen peroxide solution, ≥30%, for trace analysis
Lysine hydrochloride, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 30 wt. % in H2O, ACS reagent
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 30 wt. % in H2O, meets USP testing specifications
Sigma-Aldrich
Hydrogen peroxide solution, contains ~200 ppm acetanilide as stabilizer, 3 wt. % in H2O
Sigma-Aldrich
Hydrogen peroxide solution, contains inhibitor, 35 wt. % in H2O
Sigma-Aldrich
Hydrogen peroxide solution, 50 wt. % in H2O, stabilized
Sigma-Aldrich
Hydrogen Peroxide Solution, 30% (w/w), puriss. p.a., reag. ISO, reag. Ph. Eur.
Sigma-Aldrich
Hydrogen peroxide solution, purum p.a., ≥35% (RT)
Supelco
Hydrogen peroxide solution, 30 % (w/w), for ultratrace analysis
Sigma-Aldrich
L-Lysine monohydrochloride, BioUltra, ≥99.5% (AT)
Supelco
L-Lysine monohydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Cocaine free base
Sigma-Aldrich
L-Lysine monohydrochloride, reagent grade, ≥98% (HPLC)
Supelco
L-Lysine hydrochloride solution, 100 mM amino acid in 0.1 M HCl, analytical standard
Sigma-Aldrich
L-Lysine monohydrochloride, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
Supelco
L-Lysine monohydrochloride, certified reference material, TraceCERT®