Solid-phase microextraction (SPME) is an approach to sample preparation that has demonstrated its appropriateness for isolating/enriching analytes present in complex biofluids with minimum sample pre-treatment. Several prior in vitro and in vivo studies have used SPME to monitor the concentrations of various drugs and metabolites in blood samples. In this work, we present the results of an investigation into how various levels of hematocrit (Hct) affect SPME recoveries. The matrices for this study consisted of whole blood samples that had been adjusted at three different Hct levels (20%, 45%, and 70%), and the selected model compounds were drugs with different physicochemical characteristics (log P range from 0.33 to 6.36). In addition, two experimental setups were employed to conduct the extractions: hydrophilic lipophilic balanced (HLB) coated SPME devices (HLB-D) at 1500 rpm (vortex agitation), and mixed mode SPME fibres (MM-F) at 400 rpm (orbital shaking agitation). Our results demonstrated that the Hct effect in SPME is dependent on the analytes of interest, and that different outcomes can be attained by altering experimental conditions, such as coating type, convection, and extraction time. Interestingly, a target compound's relative affinity for the matrix components and for the coating material proved to be one of the main factors that determine the final effect that different erythrocyte levels have on SPME recoveries. Finally, although the Hct content affects each analyte differently and the final Hct effect depends on the experimental parameters, matrix variability can be corrected by using appropriate internal standards, thereby resulting in correct quantification.

中文翻译：

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血细胞比容对固相微萃取的影响

固相微萃取 (SPME) 是一种样品制备方法，已证明其适用于以最少的样品预处理分离/富集复杂生物流体中存在的分析物。之前的一些体外和体内研究已经使用 SPME 来监测血液样本中各种药物和代谢物的浓度。在这项工作中，我们展示了不同水平的血细胞比容 (Hct) 如何影响 SPME 回收率的调查结果。本研究的基质由在三种不同 Hct 水平（20%、45% 和 70%）下调整的全血样本组成，所选模型化合物是具有不同理化特性的药物（log P 范围从 0.33 到 6.36 ）。此外，采用两种实验装置进行提取：亲水亲油平衡 (HLB) 涂层 SPME 装置 (HLB-D) 在 1500 rpm (涡旋搅拌) 和混合模式 SPME 纤维 (MM-F) 在 400 rpm (轨道摇动搅拌)。我们的结果表明 SPME 中的 Hct 效应取决于感兴趣的分析物，并且可以通过改变实验条件（例如涂层类型、对流和提取时间）来获得不同的结果。有趣的是，目标化合物对基质成分和涂层材料的相对亲和力被证明是决定不同红细胞水平对 SPME 回收率的最终影响的主要因素之一。最后，虽然 Hct 含量对每种分析物的影响不同，最终 Hct 效果取决于实验参数，但可以通过使用适当的内标来校正基质变异性，