Solid-phase microextraction (SPME) coupled with liquid chromatograph (LC) is widely used to detect polar and ionic organic compounds, including various pharmaceuticals and endogenous bioactive compounds. In this study, a small-sized insert tube for use in the commercial autosampler vial was designed for eluting the extracted analytes from SPME fibers for LC analysis. By using this custom-made insert tube as an alternative to the commercial insert tube, the volume of the elution solvent was reduced by four-fifths. Even though smaller fractions of the analytes were eluted from the fiber coatings, the analyte concentrations in the elution solutions were substantially increased by using the custom-made insert tube. Therefore, larger amounts of the analytes could be injected to LC and higher signal-to-noise ratios could be achieved, even at smaller injection volumes. Since the elution in the custom-made insert tube was nonexhaustive, four strategies were developed to figure out the extracted amounts in the fiber coatings. In combination with the sampling-rate calibration method, these strategies were successfully used to determine the concentrations of fluoxetine in living tilapias. This study provides a simple but effect way for improving the analytical sensitivity when coupling SPME with LC.

中文翻译：

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通过减少离线洗脱溶剂的体积来提高固相微萃取的灵敏度

固相微萃取（SPME）结合液相色谱（LC）被广泛用于检测极性和离子有机化合物，包括各种药物和内源性生物活性化合物。在这项研究中，设计了一种用于商业自动进样器样品瓶的小型插入管，用于洗脱从SPME纤维中提取的分析物，以进行LC分析。通过使用这种定制的插入管替代商用插入管，洗脱溶剂的体积减少了五分之四。即使从纤维涂层中洗脱出了较小比例的分析物，但使用定制的插入管仍可显着提高洗脱液中的分析物浓度。因此，可以将大量的分析物注入液相色谱中，并且可以获得更高的信噪比，即使是较小的进样量。由于定制插入管中的洗脱不是穷举性的，因此开发了四种策略来确定纤维涂层中的提取量。结合采样率校准方法，这些策略已成功用于确定活罗非鱼中氟西汀的浓度。这项研究为提高SPME与LC的分析灵敏度提供了一种简单而有效的方法。