Liquid-chromatographic determination of ethylene glycol in plasma

In this novel procedure for determining ethylene glycol in plasma by liquid chromatography, benzoyl esters of ethylene glycol and of benzyl alcohol (used as the internal standard) are prepared directly in plasma. The benzoyl esters, highly ultraviolet-absorbing chromogens, are ideal compounds for analysis by reversed-phase liquid chromatography with methanol/water as the mobile phase. The benzoyl derivative of ethylene glycol is well separated from the derivative of the internal standard and from plasma constituents. The standard curve is linear to 400 mg of ethylene glycol per liter. As little as 10 mg of ethylene glycol per liter of plasma can be measured. Other commonly ingested alcohols do not interfere.