Direct quantification of cocaine in urine by time-of-flight mass spectrometry

Abstract

The direct quantification of cocaine in urine has been achieved using time-of-flight secondary-ion mass spectrometry (TOF-SIMS). The dynamic range of the TOF-SIMS is four orders of magnitude using one internal standard concentration. The limit of detection (LOD) and limit of quantification (LOQ) have been determined to be 3 ng/mL and 10 ng/mL, respectively, for MeOH standards; the LOD and LOQ have been 33 ng/mL and 100 ng/mL, respectively, in urine samples. Coefficients of variation have ranged from 0.7 to 2.7 for the MeOH standards and 2.5 to 8.0 for the urine samples. The use of TOF-SIMS to simultaneously detect multiple drugs in urine is also demonstrated. The advantages and disadvantages of directly quantifying drugs in urine are discussed. Practical considerations regarding the use of matrix-assisted laser desorption/ionization mass spectrometry for multi-component analysis are also presented.

Application of secondary ion and matrix‐assisted laser desorption‐ionization time‐of‐flight mass spectrometry for the quantitative analysis of biological molecules

“…To better understand how the etching of Ag substrates affects quantitative TOF-SIMS measurements, a systematic study was carried out using two different biomaterials (84,107). The first system was a protonated molecular species, where the role of the substrate is to support and subsequentially desorb the analyte upon ion impact; cocaine hydrochloride was used as a model compound.…”

Improvement of signal intensities in static secondary-ion mass spectrometry using halide additives and substrate modification

“…For example, analysis of cocaine hydrochloride (preformed ion) has been demonstrated directly from urine with only minimal sample treatment. 24 The detection limits from urine were decreased by a factor of 10 compared to analysis of cocaine from methanol. Neutral compounds can also be protonated in the SIMS ionization process.…”

Detection of exogenous contaminants of fingerprints using ToF‐SIMS

“…[9,10] Surface imaging and the possibility of identification of substances on the surface make ToF-SIMS a promising method in solving some important problems in forensic science. Successful results have been obtained in the detection of cocaine in urine, [11] gunshot residues (GSRs), [12] blood traces, [13] calcium and benzodiazepines in hair, [14,15] elemental distribution in hair [16] as well as elemental analysis of environmental contaminants and fragments of degradations of protein constituents in hair samples from 1000-year-old Peruvian mummies. [17] ToF-SIMS method also opens new perspectives for examination of fingerprints, especially in the visualization of fingermarks by various ions.…”