The effect of vacuum is an emerging experimental parameter to consider during optimization of a variety of headspace microextraction methodologies. The positive effect of vacuum was initially demonstrated for headspace solid-phase microextraction and was recently expanded to single-drop microextraction and higher capacity sorbents i.e. stir bar sorptive extraction. In all cases, sampling under vacuum greatly accelerated the extraction kinetics of analytes exhibiting long equilibration times under atmospheric pressure. At the same time, the extraction of analytes that reached equilibrium fast was not affected. In all optimized methods, extraction times were greatly reduced and/or sampling temperatures were lower to those reported with the standard methodology under atmospheric pressure. This work succinctly overviews the effect of vacuum on the different headspace microextraction technologies reported so far. The fundamental concepts describing the pressure dependence of each methodology are pulled together and presented in a simplified manner. The latest findings on the combined effects of vacuum and several selected experimental parameters typically examined during method optimization are then presented and the practical aspects of past outcomes are highlighted. The discussion also includes the air-evacuation step and the analysis of complex matrices. This article is intended for readers who are either new to the field of vacuum headspace microextraction sampling or its use and want to exploit this powerful approach.

Graphical abstract

真空的影响是在优化各种顶空微萃取方法时要考虑的新兴实验参数。真空的积极作用最初被证明用于顶空固相微萃取，最近扩展到单滴微萃取和更高容量的吸附剂，即搅拌棒吸附萃取。在所有情况下，在真空下取样都大大加速了在大气压下表现出较长平衡时间的分析物的提取动力学。同时，快速达到平衡的分析物的萃取不受影响。在所有优化的方法中，提取时间大大减少和/或采样温度低于标准方法在大气压下报告的温度。这项工作简要概述了真空对迄今为止报道的不同顶空微萃取技术的影响。描述每种方法的压力依赖性的基本概念被汇集在一起​​并以简化的方式呈现。然后介绍了在方法优化期间通常检查的真空和几个选定实验参数的组合效应的最新发现，并强调了过去结果的实际方面。讨论还包括抽气步骤和复杂矩阵的分析。本文适用于对真空顶空微萃取取样或其使用领域不熟悉并希望利用这种强大方法的读者。描述每种方法的压力依赖性的基本概念被汇集在一起​​并以简化的方式呈现。然后介绍了在方法优化期间通常检查的真空和几个选定实验参数的组合效应的最新发现，并强调了过去结果的实际方面。讨论还包括抽气步骤和复杂矩阵的分析。本文适用于对真空顶空微萃取取样或其使用领域不熟悉并希望利用这种强大方法的读者。描述每种方法的压力依赖性的基本概念被汇集在一起​​并以简化的方式呈现。然后介绍了在方法优化过程中通常检查的真空和几个选定实验参数的组合效应的最新发现，并强调了过去结果的实际方面。讨论还包括抽气步骤和复杂矩阵的分析。本文适用于对真空顶空微萃取取样或其使用领域不熟悉并希望利用这种强大方法的读者。然后介绍了在方法优化期间通常检查的真空和几个选定实验参数的组合效应的最新发现，并强调了过去结果的实际方面。讨论还包括抽气步骤和复杂矩阵的分析。本文适用于对真空顶空微萃取取样或其使用领域不熟悉并希望利用这种强大方法的读者。然后介绍了在方法优化期间通常检查的真空和几个选定实验参数的组合效应的最新发现，并强调了过去结果的实际方面。讨论还包括抽气步骤和复杂矩阵的分析。本文适用于对真空顶空微萃取取样或其使用领域不熟悉并希望利用这种强大方法的读者。

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