ABSTRACT
We developed a packed-column chromatographic procedure capable of simultaneous quantitation of methanol, ethanol, isopropanol, acetone, and ethylene glycol. This method was then updated to a rapid, sensitive, wide-bore capillary method. The packed-column system uses direct injection of 1 microL of Na2WO4/H2SO4-deproteinized serum onto a 1.8 m x 2 mm (i.d.) column packed with 80/100 HayeSep R. A linear temperature gradient from 90 to 205 degrees C allows complete elution of all components within 20 min; minimum detection limits are 2 mmol/L. The wide-bore capillary method uses 0.1 microL of sample deproteinized by ultrafiltration, injected onto a 30 m x 0.53 mm (i.d.) 3-microns Rtx-200 (Restek) column. Baseline resolution to a minimum detection limit of 0.1 mmol/L of all compounds is achieved in 5 min with a linear temperature gradient from 40 to 250 degrees C and dual internal standards of n-propanol and 1,2-butanediol.
Subject(s)
Alcohols/blood , Chromatography, Gas/methods , Ethylene Glycols/blood , 1-Propanol/blood , Capillary Action , Chromatography, Gas/statistics & numerical data , Ethanol/blood , Ethylene Glycol , Humans , Methanol/blood , Sensitivity and Specificity , TemperatureABSTRACT
Serum iron concentrations greater than 90 mumol/L were measured in samples from hemodialysis patients by a Ferrozine dye-binding method. Reanalysis by coulometry showed these results to be spuriously high. Turbidity resulting from precipitation of fibrinogen was identified as the source of the interference. High concentrations of heparin enhanced the effect. We conclude that the persistence of fibrinogen in serum samples from patients treated with anticoagulants is a potential interference in Ferrozine dye-binding methods performed without prior deproteinization. Adding guanidine.HCl to the acid buffer reagent is a simple way to eliminate this interference.
