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Hart ED, Vikingsson S, Winecker RE, Evans AL, Cone EJ, Mitchell JM, Hayes ED, Flegel RR. Performance of Hair Testing for Cocaine Use-Comparison of Five Laboratories Using Blind Reference Specimens. J Anal Toxicol 2023; 47:154-161. [PMID: 36039690 DOI: 10.1093/jat/bkac066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/11/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
The purpose of this study was to compare results from five commercial hair testing laboratories conducting workplace drug testing with regard to bias, precision, selectivity and decontamination efficiency. Nine blind hair specimens, including cocaine-positive drug user specimens (some contaminated with methamphetamine) and negative specimens contaminated with cocaine, were submitted in up to five replicates to five different laboratories. All laboratories correctly identified cocaine in all specimens from drug users. For an undamaged hair specimen from a cocaine user, within-laboratory Coefficients of Variation (CVs) of 5-22% (median 8%) were reported, showing that it is possible to produce a homogenous proficiency testing sample from drug user hair. Larger CVs were reported for specimens composed of blended hair (up to 29%) and curly/damaged hair (19-67%). Quantitative results appeared to be method-dependent, and the reported cocaine concentrations varied up to 5-fold between the laboratories, making interlaboratory comparisons difficult. All laboratories reported at least one positive result in specimens contaminated with cocaine powder, followed by sweat and shampoo treatments. Benzoylecgonine, norcocaine, cocaethylene and hydroxylated cocaine metabolites were all detected in cocaine powder-contaminated specimens. This indicates that current industry standards for analyzing and reporting positive cocaine results are not completely effective at identifying external contamination. Metabolite ratios between meta- or para-hydroxy-cocaine and cocaine were 6- and 10-fold lower in contaminated specimens compared to those observed in cocaine user specimens, supporting their potential use in distinguishing samples positive due to contamination and drug use.
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Affiliation(s)
- E Dale Hart
- Center for Forensic Science, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Svante Vikingsson
- Center for Forensic Science, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Ruth E Winecker
- Center for Forensic Science, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Amy L Evans
- Center for Forensic Science, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Edward J Cone
- Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD 21224, USA
| | - John M Mitchell
- Center for Forensic Science, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Eugene D Hayes
- Division of Workplace Programs, Substance Abuse and Mental Health Services Administration, 5600 Fishers Lane, Rockville, MD 20857, USA
| | - Ronald R Flegel
- Division of Workplace Programs, Substance Abuse and Mental Health Services Administration, 5600 Fishers Lane, Rockville, MD 20857, USA
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Spear BH, DeCaprio AP. Evaluation of Pretreatment and Extraction Parameters for the Analysis of Fentanyl in Hair Using Statistical Design of Experiments (DoE). J Anal Toxicol 2022; 46:932-939. [PMID: 35762492 DOI: 10.1093/jat/bkac045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/24/2022] [Accepted: 06/28/2022] [Indexed: 11/14/2022] Open
Abstract
Optimal methods for hair analysis are often debated. Previous work in this laboratory demonstrated that the statistical technique known as Design of Experiments (DoE) is useful for such optimization. DoE evaluates both the individual roles and the combinatorial associations among multiple independent variables (i.e., hair pretreatment parameters) and a dependent variable (i.e., drug recovery from hair). In this study, hair externally contaminated with fentanyl underwent decontamination with combinations of parameters based on a 24 fractional factorial block design DoE matrix. The parameters of interest included aqueous wash solvent (1% SDS or water), organic wash solvent (dichloromethane or methanol), number of consecutive washes (one or three), sequence of washes (aqueous first or organic first), and wash time (30 s or 30 min). The optimal method for decontaminating fentanyl from the hair surface was found to be one 30-min wash with dichloromethane followed by one 30-min wash with water. Pretreatment parameters were optimized with a 23 full factorial DoE matrix using authentic hair reference material (HRM), which consisted of pooled drug user hair diluted to a known concentration of fentanyl with drug-free hair. The factors of interest were extraction solvent/sample weight ratio (12.5 or 25 µL/mg), hair particle size (pulverized or 1 mm segments), and extraction time (2 or 24 h). The most effective pretreatment method for fentanyl consisted of pulverizing the hair prior to a 2-h extraction in a 25 µL/mg extraction solvent volume/sample weight ratio. Finally, using the optimized pretreatment methods, fentanyl containing authentic HRM was extracted using aqueous base, solvent, and enzymatic hair extraction methods, where it was determined that the aqueous base technique was most effective for recovery of fentanyl. These experiments further demonstrate the value of DoE and authentic HRM in method development for forensic hair analysis.
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Affiliation(s)
- Brianna Hill Spear
- Department of Chemistry and Biochemistry and the International Forensic Research Institute, Florida International University, 11200 SW Eighth Street, Miami, Florida, 33199, United States
| | - Anthony P DeCaprio
- Department of Chemistry and Biochemistry and the International Forensic Research Institute, Florida International University, 11200 SW Eighth Street, Miami, Florida, 33199, United States
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