title: Determination of urinary 5-hydroxyindoleacetic acid by combining Dμ-SPE using carbon coated TiO2 nanotubes and LC-MS/MS.
abstract: BACKGROUND
  In this article, carbon coated titanium dioxide nanotubes (TiO2-NT@C) are employed for the determination of 5-hydroxyindole-3-acetic acid in urine by LC-MS/MS.
  
  
  RESULTS
  All the variables involved in the extraction have been studied and optimized in depth. The method has been analytically characterized on the basis of its linearity, accuracy, sensitivity and precision. The LOD is 155.8 μg/l while the repeatability and the reproducibility, expressed as RSD, are better than 5.42 and 5.25%, respectively. The obtained relative recovery is 115%.
  
  
  CONCLUSIONS
  TiO2-NT@C permit the efficient extraction of 5-hydroxyindole-3-acetic acid from complex biological samples such as urine allowing its sensitive determination by LC-MS/MS.
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry & Nanochemistry, Marie Curie Building, Campus of Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: García-Valverde
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry & Nanochemistry, Marie Curie Building, Campus of Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Lucena
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry & Nanochemistry, Marie Curie Building, Campus of Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: Soledad
authors.initials: S
authors.lastname: Cárdenas
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry & Nanochemistry, Marie Curie Building, Campus of Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Valcárcel
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000302:isolation & purification* / Q000652:urine*; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014025:Titanium / Q000737:chemistry*
chemical_list: D037742:Nanotubes, Carbon; C009495:titanium dioxide; D006897:Hydroxyindoleacetic Acid; D014025:Titanium