title: Analytic validation of a gas chromatography-mass spectrometry method for quantification of six amino acids in canine serum samples.
abstract: OBJECTIVE
  To analytically validate a gas concentration of chromatography-mass spectrometry (GC-MS) method for measurement of 6 amino acids in canine serum samples and to assess the stability of each amino acid after sample storage.
  
  
  METHODS
  Surplus serum from 80 canine samples submitted to the Gastrointestinal Laboratory at Texas A&M University and serum samples from 12 healthy dogs.
  
  
  METHODS
  GC-MS was validated to determine precision, reproducibility, limit of detection, and percentage recovery of known added concentrations of 6 amino acids in surplus serum samples. Amino acid concentrations in serum samples from healthy dogs were measured before (baseline) and after storage in various conditions.
  
  
  RESULTS
  Intra- and interassay coefficients of variation (10 replicates involving 12 pooled serum samples) were 13.4% and 16.6% for glycine, 9.3% and 12.4% for glutamic acid, 5.1% and 6.3% for methionine, 14.0% and 15.1% for tryptophan, 6.2% and 11.0% for tyrosine, and 7.4% and 12.4% for lysine, respectively. Observed-to-expected concentration ratios in dilutional parallelism tests (6 replicates involving 6 pooled serum samples) were 79.5% to 111.5% for glycine, 80.9% to 123.0% for glutamic acid, 77.8% to 111.0% for methionine, 85.2% to 98.0% for tryptophan, 79.4% to 115.0% for tyrosine, and 79.4% to 110.0% for lysine. No amino acid concentration changed significantly from baseline after serum sample storage at -80°C for ≤ 7 days.
  
  
  CONCLUSIONS
  GC-MS measurement of concentration of 6 amino acids in canine serum samples yielded precise, accurate, and reproducible results. Sample storage at -80°C for 1 week had no effect on GC-MS results.
authors.forename: Rosana
authors.initials: R
authors.lastname: Lopes
authors.forename: Niels
authors.initials: N
authors.lastname: Grützner
authors.forename: Nora
authors.initials: N
authors.lastname: Berghoff
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Lidbury
authors.forename: Jan S
authors.initials: JS
authors.lastname: Suchodolski
authors.forename: Jörg M
authors.initials: JM
authors.lastname: Steiner
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000097:blood*; D000818:Animals; D004285:Dogs / Q000097:blood*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000662:veterinary*; D008297:Male; D015203:Reproducibility of Results
chemical_list: D000596:Amino Acids