Cork-based activated carbons as enrichment materials for analysis of ibuprofen and clofibric acid at trace levels in environmental matrices

摘要

In this contribution, a novel sample preparation technique for trace enrichment prior to chromatographic analysis, using cork-based activated carbons in powder form, was applied to monitor two pharmaceutical compounds. Extractions with two cork-based activated carbons followed by liquid desorption and high performance liquid chromatography with diode array detection (LD/HPLC-DAD) analysis were developed for assessment of ibuprofen and clofibric acid in real water samples and also a biologic fluid (urine). Activated carbons used present apparent surface areas around 1000 m~2 g~(-1). Sample C1 is a microporous carbon and C2 is a microporous carbon with an important development of the mesoporous structure. Both samples have basic nature: C1 has a pH_(PZC) near the neutral pH and C2 has a pH_(PZC) of 9.9. Assays performed on 30 mL water samples spiked at the 25.0 μg L~(-1) levels under optimized experimental conditions yielded recoveries between 80 and 96 %. The analytical performance showed good precision (relative standard deviation < 15 %), detection limits between 0.21 and 0.28 μg L~(-1) and linear ranges (1.0-600.0 μg L~(-1)) with r~2 > 0.99. By using the standard addition method, the application of the present method to water matrices such as surface water, wastewater, tap water, estuary water and underground water, allowed very good performances at the trace level. The present method was also applied with success to a biologic matrix, i.e. urine. The proposed methodology proved to be a suitable alternative for the analysis of polar compounds, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor these pharmaceutical compounds in environmental and biological matrices.