Drug Contamination of U.S. Paper Currency and Forensic Relevance of Canine Alert to Paper Currency: A Critical Review of the Scientific Literature

First liquid chromatography-high resolution mass spectrometry method for the determination of cocaine on banknote dust

PURPOSE

Prevalence measures of sociological interest concerning cocaine presence on banknotes are fraught with (i) the extreme variability of its concentration (seven orders of magnitude); (ii) the high number of banknotes needed for the statistical significance. Banknote dust from counting machines from a large and representative number of banknotes in circulation in a specific area represents the most eligible sample to ascertain cocaine circulation. No chromatographic method is available in this respect. This study aims at developing the first analytical methodology for the determination of cocaine in banknote dust samples.

METHODS

This novel and straightforward approach consists of a simple methanol extraction followed by analytical determinations via ultra-high performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry.

RESULTS

Satisfactory analytical performance was obtained with a coefficient of determination of 0.996; maximum within-run and between-run precisions were, respectively, 1.85% and 5.20%. Limits of detection and quantification were, respectively, 3 and 9 ng/mL with an overall process efficiency of 93.2%. The method developed was successfully applied to 9 banknote dust samples from local banknote counter machines. The found concentrations ranged from 2.18E + 02 to 2.31E + 03 μg of cocaine per gram of banknote dust and varied only one order of magnitude, much less than cocaine concentration on banknotes.

CONCLUSIONS

To have an idea of cocaine circulation in a geographical area, the sampling of banknote dust, compared to banknotes, consists of tremendous advantages in terms of statistical significance, higher cocaine concentrations, and lower variability: this is crucial from the sociological point of view.

Determination of Cocaine on Banknotes Using Innovative Sample Preparation Coupled With Multiple Calibration Techniques

A method using innovative sample preparation was developed for determination of cocaine on banknotes. Aqueous extraction of cocaine from banknotes was performed using a sonication‐enhanced technique. Quantitation of cocaine was achieved using high performance liquid chromatography (HPLC) with UV detection at 230 nm, whereas identification was accomplished utilizing gas chromatography with mass spectrometry (GC‐MS). Multiple calibration techniques, including the external calibration method (ECM), internal standard method (ISM), and standard addition method (SAM) were incorporated into the experimental design to simultaneously determine cocaine contents and assess matrix effects. Statistical paired t tests confirmed that matrix effects were not significant with the sample preparation employed. No damage to the features of the banknotes was observed from the extraction procedure. Extraction efficiency, spike recovery, and detection limit were also determined. The unique experimental design allowed for ECM, ISM, and SAM to concurrently determine the contents of cocaine on banknotes collected around Metro‐Detroit. The concentration range of cocaine was from 1.58 to 14.7 μg per note, with an average of 6.96 μg per note. The method is simple and suitable for drug analysis and forensic science applications.

Isobutylene contamination of blood collected in 10-ml evacuated blood collection tubes with gray conventional rubber stoppers

Dual-column headspace gas chromatographic analysis with two flame-ionization detectors is a commonly used analytical technique for forensic blood ethanol quantitation. This technique is also applicable to the identification and quantitation of other volatile organic compounds such as methanol in biological samples. Compound identification by retention time is limited to those compounds with known retention times programmed into the instrument method. Historically, an early-eluting peak from an unidentified compound has been observed in both chromatograms from antemortem blood samples analyzed for ethanol concentration with this technique. The unidentified compound's retention time matches that of methanol on one column but not on the second column. This previously unidentified compound has been identified as isobutylene. The proposed source of the isobutylene contamination historically observed in antemortem blood samples collected in 10-ml gray-top blood collection tubes is the conventional rubber stopper. Isobutylene was detected in deionized water stored in each of the seven lots of 10-ml blood tubes tested; the expiration dates of the tubes tested spanned the years 2002-2022. Misidentification of isobutylene as methanol is possible when using a single-column gas chromatographic system. The presence of isobutylene in blood collected in a gray-top collection tube does not represent laboratory contamination, is not an interferent with blood ethanol quantitation, and does not affect the ethanol concentration in the blood. A 0.150 g/dl aqueous ethanol standard was stored in a gray-top tube to evaluate the potential impact of isobutylene on ethanol quantitation. The solution's average ethanol concentration measured after storage was 0.150 g/dl.

A multi-laboratory investigation of drug background levels

Identifying and quantifying the drug background in operational environments such as forensic laboratories is an emerging body of research. Knowing these levels is crucial to addressing issues like occupational exposure risk - due to the emergence of potent novel psychoactive substances and synthetic opioids - and data integrity - due to improvements in instrument sensitivity. The work presented here builds upon a prior study to provide a broader representation of the average drug background levels found on surfaces in forensic laboratories. Over 700 samples from 20 laboratories were collected, extracted, and analyzed quantitatively using LC-MS/MS, and qualitatively using TD-DART-MS. Quantitative analysis by LC-MS/MS included a panel of 18 drugs while the non-targeted qualitative analysis by TD-DART-MS screened for over three hundred drugs and excipients. The study focused primarily on surfaces within the drug unit and evidence receiving area of the laboratories, but also investigated other operational units (crime scene, drug interdiction, latent prints, and toxicology) as well as report writing. Background levels were highest within the drug unit of the laboratory, though detectable (tens of nanograms) levels were observed in nearly all sampled areas. The data from this expanded study plays a critical role in addressing laboratory concerns such as establishing drug identification reporting limits for new instrumentation and establishing new workflow or cleaning protocols while also providing a more comprehensive dataset for general environmental background studies.