Tags

Type your tag names separated by a space and hit enter

Phentermine interference and high L-methamphetamine concentration problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride-derivatized amphetamines and methamphetamines†.
J Anal Toxicol. 2014 Sep; 38(7):456-61.JA

Abstract

In order to achieve chromatographic separation, urine samples shown to be initially positive for amphetamines and methamphetamines in US Department of Defense immunoassays are derivatized with R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride (R-(-)-MTPA) prior to gas chromatography-electron impact-mass spectrometry (GC-EI-MS) analysis. Phentermine, a member of the phenethylamine class of drugs and a common appetite suppressant, interferes with GC-EI-MS assays of R-(-)-MTPA-derivatized d-amphetamine, degrading the chromatography of the internal standard and analyte ions and skewing concentration calculations. Additionally, when specimens with high concentrations of l-methamphetamine are derivatized with R-(-)-MTPA, signal peaks have the potential to be misidentified by integration software as d-methamphetamine. We have found that replacing R-(-) MTPA with (S)-(+)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride reduces phentermine interference problems related to internal standard chromatography, reduces the possibility of concentrated l-methamphetamine peaks being misidentified by integration software, improves resolution of d-methamphetamine in the presence of high l-methamphetamine concentrations, and is a cost-neutral change that can be applied to current amphetamines GC-EI-MS methods without the need for method modification.

Authors+Show Affiliations

Department of Chemistry, United States Naval Academy, Annapolis, MD, USA theron@usna.edu.Department of Chemistry, United States Naval Academy, Annapolis, MD, USA.Department of Chemistry, United States Naval Academy, Annapolis, MD, USA.United States Army Forensic Toxicology Drug Testing Laboratory, Fort Meade, MD, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

24951536

Citation

Hamilton, Theron J., et al. "Phentermine Interference and High L-methamphetamine Concentration Problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl Chloride-derivatized Amphetamines and Methamphetamines†." Journal of Analytical Toxicology, vol. 38, no. 7, 2014, pp. 456-61.
Hamilton TJ, Qui HZ, Dozier KV, et al. Phentermine interference and high L-methamphetamine concentration problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride-derivatized amphetamines and methamphetamines†. J Anal Toxicol. 2014;38(7):456-61.
Hamilton, T. J., Qui, H. Z., Dozier, K. V., & Fuller, Z. J. (2014). Phentermine interference and high L-methamphetamine concentration problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride-derivatized amphetamines and methamphetamines†. Journal of Analytical Toxicology, 38(7), 456-61. https://doi.org/10.1093/jat/bku069
Hamilton TJ, et al. Phentermine Interference and High L-methamphetamine Concentration Problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl Chloride-derivatized Amphetamines and Methamphetamines†. J Anal Toxicol. 2014;38(7):456-61. PubMed PMID: 24951536.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Phentermine interference and high L-methamphetamine concentration problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride-derivatized amphetamines and methamphetamines†. AU - Hamilton,Theron J, AU - Qui,Harry Z, AU - Dozier,Katherine V R, AU - Fuller,Zachary J, Y1 - 2014/06/20/ PY - 2014/6/22/entrez PY - 2014/6/22/pubmed PY - 2015/4/9/medline SP - 456 EP - 61 JF - Journal of analytical toxicology JO - J Anal Toxicol VL - 38 IS - 7 N2 - In order to achieve chromatographic separation, urine samples shown to be initially positive for amphetamines and methamphetamines in US Department of Defense immunoassays are derivatized with R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride (R-(-)-MTPA) prior to gas chromatography-electron impact-mass spectrometry (GC-EI-MS) analysis. Phentermine, a member of the phenethylamine class of drugs and a common appetite suppressant, interferes with GC-EI-MS assays of R-(-)-MTPA-derivatized d-amphetamine, degrading the chromatography of the internal standard and analyte ions and skewing concentration calculations. Additionally, when specimens with high concentrations of l-methamphetamine are derivatized with R-(-)-MTPA, signal peaks have the potential to be misidentified by integration software as d-methamphetamine. We have found that replacing R-(-) MTPA with (S)-(+)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride reduces phentermine interference problems related to internal standard chromatography, reduces the possibility of concentrated l-methamphetamine peaks being misidentified by integration software, improves resolution of d-methamphetamine in the presence of high l-methamphetamine concentrations, and is a cost-neutral change that can be applied to current amphetamines GC-EI-MS methods without the need for method modification. SN - 1945-2403 UR - https://www.unboundmedicine.com/medline/citation/24951536/Phentermine_interference_and_high_L_methamphetamine_concentration_problems_in_GC_EI_MS_SIM_Analyses_of_R_____α_methoxy_α__trifluoromethyl_phenylacetyl_chloride_derivatized_amphetamines_and_methamphetamines†_ L2 - https://academic.oup.com/jat/article-lookup/doi/10.1093/jat/bku069 DB - PRIME DP - Unbound Medicine ER -