Quantitative endogenous formate analysis in plasma using headspace gas chromatography without a headspace analyzer.
The objective was to develop a simple routine method for quantitative measurement of endogenous formic acid in plasma and whole blood using headspace gas chromatography-flame ionization detection. (GC-FID). Two-hundred microliters of sample was placed in a 1-mL glass vial. Fifty microliters of aqueous ethanol (10%) was added as an internal standard and a derivatizing agent. Ethylformate formation was enhanced by addition of 200 microL concentrated sulfuric acid as a catalyst. The vials were then sealed immediately and placed in a water bath for 15 min at 60 degrees C. One milliliter of this headspace gas was siphoned using a gas-tight syringe and injected into a GC-FID fitted with a capillary column. Ethanol eluted at approximately 3.0 min, and ethylformate eluted around 4.7 min. The limit of quantitation for ethylformate was 0.026 mmol/L, and the limit of detection was 0.020 mmol/L. Imprecisions for spiked plasma samples at 0.25 and 1 mmol/L were 10% and 9%, respectively and recoveries were at 100% and 108%, respectively. A simple, reliable, and highly specific headspace analysis method for quantifying endogenous formate without the use of a headspace analyzer was developed. This method enables the routine clinical analysis of formate in plasma and whole blood samples.
Sokoro
AbdulRazaq
A
Toxicology, Saskatchewan Disease Control Laboratory, 3211 Albert Street, Regina, Saskatchewan, S4S 5W6, Canada.
Lehotay
Denis
D
Eichhorst
Jeff
J
Treble
Ronald
R
D000818:Animals; D002849:Chromatography, Gas / Q000379:methods; D005260:Female; D005410:Flame Ionization; D005561:Formates / Q000097:blood*; D006801:Humans; D011247:Pregnancy; D013552:Swine
D005561:Formates; C030544:formic acid