Sample treatment platform for automated integration of microextraction techniques and liquid chromatography analysis

摘要

Sample preparation performance influences the quality of every chemical analysis. Since it is the most labor-intensive stage in the nearly all-analytical protocols, sample preparation automation would be desirable, to increase the analytical throughput, maintaining precision and accuracy, while preventing risks of human exposure to chemical or biological agents. Among different lab-automation strategies, robots have long been an important prospect. Nevertheless, widespread adoption of dedicate “robot-chemist” with analytical purposes continues being limited. Open resources that enable non-specialist analysts and researchers to make their own prototypes are still necessary. We have assembled an open-source innovative platform, able to guarantee the online hyphenation of the sample preparation microtechniques with liquid chromatography, mass spectrometry or any other detection system. It is a multi-purpose cartesian robot, programmed to perform sample clean-up operations, allowing the automated pre-concentration of analytes through the performance of solid and liquid phase microextraction protocols, actuating a microextraction syringe driver, and equipped with an in-syringe-stirring mechanism and an adapted interface for online coupling with liquid chromatography or mass spectrometry analysis. The entire sample preparation procedure can be performed by the developed prototype and the enriched extract automatically injected into the separation and detection system. The analytical performance of the developed prototype was assessed for the extraction of polyaromatic hydrocarbons from sewage water, by headspace dynamic single drop microextraction (SDME), dynamic hollow-fiber liquid phase microextraction (HF-LPME) and microextraction by packed sorbent (MEPS). The developed prototype displayed excellent precision and accuracy for the execution of the microextraction protocols, proving to be a promising and competitive open source analytical tool able to extend the state-of-the-art of sample preparation microtechniques.