title: Micro-pulverized extraction pretreatment for highly sensitive analysis of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol in hair by liquid chromatography/tandem mass spectrometry.
abstract: BACKGROUND
  A primary metabolite of Δ(9) -tetrahydrocannabinol, 11-nor-9-carboxytetrahydrocannabinol (THC-COOH), serves as an effective indicator for cannabis intake. According to the recommendations of the Society of Hair Testing, at least 0.2 pg/mg of THC-COOH (cut-off level) must be present in a hair sample to constitute a positive result in a drug test. Typically, hair is digested with an alkaline solution and is subjected to gas chromatography/tandem mass spectrometry (GC/MS/MS) with negative ion chemical ionization (NICI).
  
  
  METHODS
  It is difficult to quantify THC-COOH at the cut-off level using liquid chromatography/tandem mass spectrometry (LC/MS/MS) without acquisition of second-generation product ions in triple quadrupole-ion trap mass spectrometers, because large amounts of matrix components in the low-mass range produced by digestion interfere with the THC-COOH peak. Using the typical pretreatment method (alkaline dissolution) and micro-pulverized extraction (MPE) with a stainless bullet, we compared the quantification of THC-COOH using GC/MS/MS and LC/MS/MS.
  
  
  RESULTS
  MPE reduced the amount of matrix components in the low-mass range and enabled the quantification of THC-COOH at 0.2 pg/mg using a conventional triple quadrupole liquid chromatograph coupled to a mass spectrometer. On the other hand, the MPE pretreatment was unsuitable for GC/MS/MS, probably due to matrix components in the high-mass range. The proper combination of pretreatments and instrumental analyses was shown to be important for detecting trace amounts of THC-COOH in hair.
  
  
  CONCLUSIONS
  In MPE, samples can be prepared rapidly, and LC/MS/MS is readily available, unlike GC/MS/MS with NICI. The combination of MPE and LC/MS/MS might therefore be used in the initial screening for THC-COOH in hair prior to confirmatory analysis using GC/MS/MS with NICI.
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kuwayama
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Miyaguchi
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yamamuro
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Tsujikawa
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Kanamori
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Yuko T
authors.initials: YT
authors.lastname: Iwata
authors.affiliation: National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D006197:Hair / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol