It is believed that the ultimate goal of analytical chemistry is to develop the accurate, sensitive and selective method for the analytical projects in daily life. Smooth coupling of SP and consequent detection procedure can result in the online SP-detection systems and would finally realize the ultimate goal of analytical chemistry with the fastest speed and least labor as much as possible. Nowadays, many online SP-LC systems have been developed for the efficient separation and analysis of trace target compounds with some core interface techniques mainly including online injector, autosampler, SPME interface and column switching technique. However, most of these online SP-LC systems proposed nowadays
are “partially automated” but not “fully automated” systems. There are few commercially available online SP-LC systems such as SPELC and MD-LC systems, which limits the application of online SP-LC systems in routine analysis. With the introduction of new extraction materials during SP procedure and new LC techniques such as nanoLC and UPLC, the online SP-LC system will be more and more miniaturized and easy to be commercially produced. In the future,
it is expected that online SP-LC techniques will be an important research field in analytical chemistry and gain more attention in scientific research and routine analysis.