Solid phase extraction for the determination of ibuprofen by means of HPLC and UV detection in the lower ng range in plasma and urine

Ibuprofen in the lower ng range could, up to now, only be determined in biological samples by means of specific detectors. In the following a time-saving HPLC method with UV detection after solid phase extraction is described. The lower detection limit is 0.5 ng/20 µl of sample volume. The linear range is between 0 and 10.0 ng of ibuprofen per injection. The mean standard deviation and mean coefficient of variation are 0.12 ng and 2.6%. The selectivity of the method is assured.