Determination of residual solvents and reagents in X-ray contrast media by automatic static headspace capillary gas chromatography

A specific, sensitive, and simple method for the quantitation of residual methanol, 2‐propanol, 2‐butanol, 2‐methoxy‐1‐ethanol, 1‐chloro‐3‐methoxy‐2‐propanol, 3‐chloro‐2‐methoxy‐1‐propanol, and 1,3‐dimethoxy‐2‐propanol in two non‐ionic X‐ray contrast media, has been developed. The headspace of a 25 % w/V aqueous solution of contrast media, obtained at 90–110°C in 15 min, was injected onto a capillary column coated with cyanopropyl, phenyl, dimethylpolysiloxane polymer. The internal standards used were 2‐pentanol and 3‐methoxy‐1‐butanol. The limits of detection were below 5 μg/g. The repeatability of the method at 50 μg/g of each solvent was below 5 %; and at 100 μg/g of the methoxypropanol compounds and 2‐methoxy‐1‐ethanol, below 10 % (RSD, N = 5).