title: High performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS) assay for chiral separation of lactic acid enantiomers in urine using a teicoplanin based stationary phase.
abstract: A novel method for the separation and simultaneous determination of urinary D- and L-lactic acid enantiomers by high performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS) is presented. The chiral separation was optimized on a Chirobiotic teicoplanin aglyocone (TAG) column. Most interestingly, the addition of water in small volume fraction to the polar organic mobile phase was found to significantly improve the chromatography. Calibration curves were linear (r2>0.9950) over the range 3-1000 mg/L for L-lactic acid and 0.5-160.8 mg/L for D-lactic acid. The limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) were determined experimentally (n=3) to be 0.2 and 0.5mg/L for L-lactic acid and 0.4 and 1.3 mg/L for D-lactic acid, respectively. The normal patient range of L-lactic acid was 1-20 microg/mg creatinine with an elevated value of 85 microg/mg creatinine. For D-lactic acid, the range of normal values were between 0 and 5 microg/mg creatinine with an elevated value of 40 microg/mg creatinine. Finally, the validated method allows for rapid analysis with a total run time of 7.5 min.
authors.affiliation: Analytical Department, Metametrix Clinical Laboratory, 4855 Peachtree Industrial Blvd., Suite 201, Norcross, GA 30092, USA. dnorton@metametrix.com
authors.forename: Dean
authors.initials: D
authors.lastname: Norton
authors.forename: Brian
authors.initials: B
authors.lastname: Crow
authors.forename: Michael
authors.initials: M
authors.lastname: Bishop
authors.forename: Kasey
authors.initials: K
authors.lastname: Kovalcik
authors.forename: Joe
authors.initials: J
authors.lastname: George
authors.forename: J Alexander
authors.initials: JA
authors.lastname: Bralley
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D019344:Lactic Acid / Q000302:isolation & purification* / Q000652:urine; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*; D017334:Teicoplanin / Q000737:chemistry*
chemical_list: D019344:Lactic Acid; D017334:Teicoplanin