title: Development, validation and clinical evaluation of a dried urine spot method for determination of hippuric acid and creatinine.
abstract: OBJECTIVE
  The purpose of this study was to develop and validate a HPLC-DAD method for determination of creatinine and hippuric acid in dried urine spots (DUS), evaluating its clinical applicability.
  
  
  METHODS
  Sample preparation was based on a simple one step extraction with water. Analysis was performed in a reversed phase column Hypersil Gold C18 (150 × 4.6 mm, 3 μm) with isocratic elution. Mobile phase was a mixture of triethylammonium phosphate buffer 5 mM, pH 3.3 and acetonitrile (90:10, v/v).
  
  
  RESULTS
  Total analytical run time was 6 min. Precision assays presented CV% lower than 11.8%. Accuracy was 96.0-103%. The lower limit of quantitation was 50 mg L(-1). Mean extraction yields were 99% for CR and 79.3% for HA. Analytes were stable in DUS up to 11 days at 40 °C. The method was tested in 49 paired DUS and urine samples, with acceptable agreement. HA-CR concentration ratios in DUS were in the range of 0.06 to 2.74, being in average 100.7% from those values found in urine.
  
  
  CONCLUSIONS
  DUS samples are a useful alternative for biological monitoring of toluene occupational exposure, especially in Developing Countries where sample logistics could be an important concern.
authors.affiliation: Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil. marinaantunes@feevale.br
authors.forename: Marina Venzon
authors.initials: MV
authors.lastname: Antunes
authors.forename: Camila Ghani
authors.initials: CG
authors.lastname: Niederauer
authors.forename: Rafael
authors.initials: R
authors.lastname: Linden
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003404:Creatinine / Q000652:urine*; D006626:Hippurates / Q000652:urine*; D006801:Humans; D016273:Occupational Exposure; D014050:Toluene / Q000633:toxicity
chemical_list: D006626:Hippurates; D014050:Toluene; D003404:Creatinine; C030514:hippuric acid
keywords: Creatinine; Dried urine spots; HPLC; Hippuric acid