Automated on-line solid-phase extraction coupled with HPLC for measurement of 5-hydroxyindole-3-acetic acid in urine.
BACKGROUND
Quantification of 5-hydroxyindole-3-acetic acid (5-HIAA) in urine is useful in diagnosing and monitoring of patients with carcinoid tumors and in the study of serotonin (5-hydroxytryptamine) metabolism in various disorders. We describe an automated method that incorporates on-line solid-phase extraction (SPE) and HPLC to measure urinary 5-HIAA.


METHODS
Automated prepurification of urine was accomplished with HySphere-resin GP SPE cartridges containing strong hydrophobic polystyrene resin. The analyte (5-HIAA) and internal standard [5-hydroxyindole-3-carboxylic acid (5-HICA)] were eluted from the SPE cartridge, separated by reversed-phase HPLC, and detected fluorometrically with a total cycle time of 20 min. Urinary excretion of 5-HIAA was measured in a group of patients with known and suspected carcinoid tumors (n=63) and in 20 patients with autism.


RESULTS
The internal standard (5-HICA) and 5-HIAA were recovered in high yields (87.2%-114%). Within- and between-series CVs for the measurement of 5-HIAA in urine ranged from 1.2% to 3.9% and 3.2% to 7.6%, respectively. For urine samples from patients with known or suspected carcinoid tumors, results obtained by the automated method were highly correlated (r=0.988) with those from an established manual extraction method. For samples from autistic patients, urinary excretion of 5-HIAA was similar to that reported for healthy individuals.


CONCLUSIONS
This SPE-HPLC method demonstrated lower imprecision and time per analysis than the manual solvent extraction method.
Mulder
Erik J
EJ
Child and Adolescent Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Oosterloo-Duinkerken
Alida
A
Anderson
George M
GM
De Vries
Elisabeth G E
EG
Minderaa
Ruud B
RB
Kema
Ido P
IP
D001321:Autistic Disorder / Q000175:diagnosis; D001322:Autoanalysis; D015415:Biomarkers / Q000652:urine; D002276:Carcinoid Tumor / Q000175:diagnosis; D002851:Chromatography, High Pressure Liquid; D005470:Fluorometry; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine*; D011786:Quality Control
D015415:Biomarkers; D006897:Hydroxyindoleacetic Acid