Identification of five Mitragyna alkaloids in urine using liquid chromatography-quadrupole/time of flight mass spectrometry

J Chromatogr B Analyt Technol Biomed Life Sci. 2018 Mar 30;1080:11-19. doi: 10.1016/j.jchromb.2018.02.010. Epub 2018 Feb 13.


Mitragyna speciosa (Kratom) is a psychoactive plant that has recently emerged as a recreational drug. Mitragyna alkaloids are not within the scope of traditional forensic toxicology screening methods, which may contribute to under-reporting. Solid phase extraction (SPE) and liquid chromatography-quadrupole/time of flight mass spectrometry (LC-Q/TOF-MS) were used to identify five alkaloids in urine. Target analytes included the two known psychoactive compounds, mitragynine and 7-hydroxymitragynine, in addition to speciociliatine, speciogynine, and paynantheine. Two deuterated internal standards (mitragynine-D3 and 7-hydroxymitragynine-D3) were employed. Using traditional reversed phase chromatography all compounds and isomers were separated in 10 min. The procedure was validated in accordance with the Scientific Working Group for Forensic Toxicology (SWGTOX) Standard Practices for Method Validation. Extraction efficiencies were 63-96% and limits of quantitation were 0.5-1 ng/mL. Precision, bias and matrix effects were all within acceptable thresholds, with the exception of 7-hydroxymitragynine, which is notably unstable and unsuitable for quantitative analysis. In this paper we present a simultaneous quantitative analytical method for mitragynine, speciociliatine, speciogynine and paynantheine, and a qualitative assay for 7-hydroxymitragynine in urine using high resolution mass spectrometry (HRMS).

Keywords: HRMS; Kratom; LC-Q/TOF-MS; Mitragynine; Urine.

MeSH terms

  • Chromatography, Liquid / methods*
  • Humans
  • Limit of Detection
  • Nonlinear Dynamics
  • Reproducibility of Results
  • Secologanin Tryptamine Alkaloids / chemistry
  • Secologanin Tryptamine Alkaloids / isolation & purification
  • Secologanin Tryptamine Alkaloids / urine*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*


  • Secologanin Tryptamine Alkaloids
  • 7-hydroxymitragynine
  • mitragynine