Preparation of ferrofluid from toner powder and deep eutectic solvent used in air-assisted liquid-liquid microextraction: Application in analysis of sixteen polycyclic aromatic hydrocarbons in urine and saliva samples of tobacco smokers

A new ferrofluid prepared from toner powder and deep eutectic solvent was used in air-assisted liquid-liquid microextraction procedure for extraction of sixteen polycyclic aromatic hydrocarbons from urine and saliva samples of tobacco smokers. In this work, initially, a water-immiscible deep eutectic solvent is synthesized by mixing choline chloride and stearic acid under mild conditions and used as a support solvent in the preparation of ferrofluid from toner powder. Then, a few microliters of the prepared ferrofluid is mixed with sample solution and dispersed in all parts of the solution by performing aspirating/dispersing cycles. To collect the ferrofluid, a magnet is deposited at the outside of the tube and the solution is discarded. The analytes in the collected phase are back-extracted into n-heptane and determined by gas chromatography-mass spectrometry. The validation parameters including limit of detection and quantification, stability, accuracy, linearity, selectivity, precision, enrichment factor, and extraction recovery were studied and the data showed that the method have low limits of detection (in the range of 6-21 ng L-1 in deionized water and 18-63 ng L-1 in saliva and urine samples, respectively) and quantification (in the range of 20-72 ng L-1 in deionized water and 60-216 ng L-1 in saliva and urine samples). Extraction recoveries and enrichment factors ranged from 61 to 84% and 305 to 420, respectively. Relative standard deviations of <= 9% for the extraction of 200 ng L(-1)of each analyte were obtained for infra- (n = 6) and inter-day (n = 6) precisions. Finally, urine and saliva samples of tobacco smokers were successfully analyzed using the proposed method.