Rapid GLD determination of ibuprofen in serum

A rapid procedure for the determination of ibuprofen in human serum was developed using a single extraction with carbon tetrachloride after deproteinization with perchloric acid. The internal standard, 3-methyl-3-phenylbutyric acid, was added directly to the serum. Gas chromatograms were free of interfering peaks. Calibration curves (0--40 micron g/ml) were linear with a sensitivity of 0.5 micron of ibuprofen/ml of serum. Relative standard deviations ranged from 1.1 to 25%.