Quantification of urinary zwitterionic organic acids using weak-anion exchange chromatography with tandem MS detection.
A rapid and accurate quantitative method was developed and validated for the analysis of four urinary organic acids with nitrogen containing functional groups, formiminoglutamic acid (FIGLU), pyroglutamic acid (PYRGLU), 5-hydroxyindoleacetic acid (5-HIAA), and 2-methylhippuric acid (2-METHIP) by liquid chromatography tandem mass spectrometry (LC/MS/MS). The chromatography was developed using a weak anion-exchange amino column that provided mixed-mode retention of the analytes. The elution gradient relied on changes in mobile phase pH over a concave gradient, without the use of counter-ions or concentrated salt buffers. A simple sample preparation was used, only requiring the dilution of urine prior to instrumental analysis. The method was validated based on linearity (r2>or=0.995), accuracy (85-115%), precision (C.V.<12%), sample preparation stability (<or=5%, 72 h), and established patient ranges. The method was found to be both efficient and accurate for the analysis of urinary zwitterionic organic acids.
Bishop
Michael Jason
MJ
Metametrix Clinical Laboratory, 4855 Peachtree Ind. Blvd. Norcross, GA 30092, USA. mbishop@metametrix.com
Crow
Brian S
BS
Kovalcik
Kasey D
KD
George
Joe
J
Bralley
James A
JA
D000143:Acids / Q000737:chemistry / Q000652:urine*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000837:Anion Exchange Resins; D002852:Chromatography, Ion Exchange / Q000379:methods*; D005565:Formiminoglutamic Acid / Q000737:chemistry / Q000652:urine; D006626:Hippurates / Q000737:chemistry / Q000652:urine; D006801:Humans; D008875:Middle Aged; D015394:Molecular Structure; D009930:Organic Chemicals / Q000737:chemistry / Q000652:urine; D011761:Pyrrolidonecarboxylic Acid / Q000737:chemistry / Q000652:urine; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
D000143:Acids; D000837:Anion Exchange Resins; D006626:Hippurates; D009930:Organic Chemicals; C026113:2-methylhippuric acid; D005565:Formiminoglutamic Acid; D011761:Pyrrolidonecarboxylic Acid