Abstract 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−1of each analyte were obtained for intra– (n = 6) and inter–day (n = 6) precisions. Finally, urine and saliva samples of tobacco smokers were successfully analyzed using the proposed method.

中文翻译：

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空气辅助液-液微萃取用碳粉和深共熔溶剂制备铁磁流体：在吸烟者尿液和唾液样品中分析 16 种多环芳烃中的应用

摘要 以碳粉和低共熔溶剂制备的新型铁磁流体用于空气辅助液-液微萃取过程，从吸烟者的尿液和唾液样品中提取16种多环芳烃。在这项工作中，最初，通过在温和条件下混合氯化胆碱和硬脂酸合成了一种与水不混溶的低共熔溶剂，并将其用作碳粉制备铁磁流体的载体溶剂。然后，将几微升制备的铁磁流体与样品溶液混合，并通过执行抽吸/分散循环分散在溶液的所有部分。为了收集铁磁流体，将磁铁放置在管的外部，然后丢弃溶液。收集相中的分析物被反萃取到正庚烷中，并通过气相色谱-质谱法进行测定。对包括检测限和定量限、稳定性、准确度、线性、选择性、精密度、富集因子和提取回收率在内的验证参数进行了研究，数据表明该方法具有较低的检测限（范围为 6-21 ng L -1 在去离子水中和 18-63 ng L-1 分别在唾液和尿液样本中）和定量（在去离子水中 20-72 ng L-1 和唾液和尿液中 60-216 ng L-1样品）。提取回收率和富集因子的范围分别为 61% 至 84% 和 305% 至 420%。提取 200 ng L−1 每种分析物的相对标准偏差≤9%，获得了内 (n = 6) 和日间 (n = 6) 精度。最后，