title: Determination of dimethyltryptamine and β-carbolines (ayahuasca alkaloids) in plasma samples by LC-MS/MS.
abstract: BACKGROUND
  Ayahuasca is a psychoactive plant beverage originally used by indigenous people throughout the Amazon Basin, long before its modern use by syncretic religious groups established in Brazil, the USA and European countries. The objective of this study was to develop a method for quantification of dimethyltryptamine and β-carbolines in human plasma samples.
  
  
  RESULTS
  The analytes were extracted by means of C18 cartridges and injected into LC-MS/MS, operated in positive ion mode and multiple reaction monitoring. The LOQs obtained for all analytes were below 0.5 ng/ml. By using the weighted least squares linear regression, the accuracy of the analytical method was improved at the lower end of the calibration curve (from 0.5 to 100 ng/ml; r(2)> 0.98).
  
  
  CONCLUSIONS
  The method proved to be simple, rapid and useful to estimate administered doses for further pharmacological and toxicological investigations of ayahuasca exposure.
authors.affiliation: University of São Paulo, São Paulo, SP, Brazil. cdro@usp.br
authors.forename: Carolina Dizioli Rodrigues
authors.initials: CD
authors.lastname: Oliveira
authors.forename: Guilherme Gonçalves
authors.initials: GG
authors.lastname: Okai
authors.forename: José Luiz
authors.initials: JL
authors.lastname: da Costa
authors.forename: Rafael Menck
authors.initials: RM
authors.lastname: de Almeida
authors.forename: Diogo
authors.initials: D
authors.lastname: Oliveira-Silva
authors.forename: Mauricio
authors.initials: M
authors.lastname: Yonamine
mesh_terms: D000818:Animals; D031581:Banisteriopsis / Q000009:adverse effects* / Q000737:chemistry; D002138:Calibration; D002243:Carbolines / Q000008:administration & dosage / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods; D005260:Female; D006801:Humans; D026121:Indole Alkaloids / Q000008:administration & dosage / Q000097:blood*; D016018:Least-Squares Analysis; D057230:Limit of Detection; D008297:Male; D004130:N,N-Dimethyltryptamine / Q000008:administration & dosage / Q000097:blood*; D010936:Plant Extracts / Q000008:administration & dosage; D051381:Rats; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D002243:Carbolines; D026121:Indole Alkaloids; D010936:Plant Extracts; D004130:N,N-Dimethyltryptamine