Molecularly imprinted polymer based-solid phase extraction combined with dispersive liquid–liquid microextraction using new deep eutectic solvent; selective extraction of valproic acid from exhaled breath condensate samples

Abstract

A solid phase extraction method has been reported based on a molecularly imprinted polymer combined with deep eutectic solvents-dispersive liquid–liquid microextraction characterized by gas chromatography–mass spectrometry for the extraction and quantification of valproic acid from exhaled breath condensate samples. First, the molecularly imprinted polymer was synthesized using a precipitation polymerization method with valproic acid as a template and then it was used as a sorbent for the analyte extraction. Next, the adsorbed analyte was eluted from the sorbent using a water-miscible deep eutectic solvent prepared from N,N-dimethyl ammonium chloride: propionic acid. After collecting the eluant, it was mixed with 8-hydroxyquinolin: dichloroacetic acid: pivalic acid deep eutectic solvent as an extraction solvent with the mixture applied in the sequential microextraction method. The method provided low limits of detection and quantification of 0.04 and 0.13 ng mL−1 as well as 0.08 and 0.26 ng mL−1 in deionized water and the exhaled breath condensate, respectively. The method had proper repeatability, accuracy, and stability expressed as relative standard deviations less than 4.9, 13, and 18%, respectively. The validated method was successfully performed on different exhaled breath condensate samples obtained from the patients who were under treatment with valproic acid.