A review of current trends and advances in modern bio-analytical methods: chromatography and sample preparation.

Any bio-analytical method includes several steps, all of them being important in order to achieve reliable results. The first step is taking aliquots of samples for the analysis, followed by the extraction procedure and sample clean-up, chromatographic analysis and detection. Chromatographic methods, particularly liquid chromatography, are the methods of choice in bio-analytical laboratories. Current trends in fast liquid chromatographic separations involve monolith technology, fused core columns, high temperature liquid chromatography and ultra-high performance liquid chromatography (UHPLC). UHPLC has recently become a wide-spread analytical technique in many laboratories which focus on fast and sensitive bio-analytical assays. The key advantages of UHPLC are the increased speed of analysis, higher separation efficiency and resolution, higher sensitivity and much lower solvent consumption as compared to other analytical approaches. This is all enabled by specially designed instruments and sub-2-microne particle packed analytical columns. There is a great contrast between ultra-fast chromatographic analysis and conventional sample preparation, which remains highly labor-intensive and time-consuming. Conventional sample preparation techniques including SPE, solid phase extraction; LLE, liquid-liquid extraction; PP, protein precipitation and many modern approaches (RAM, restricted access material; MIP, molecularly imprinted polymers; SPME, solid phase microextraction; LLME, liquid-liquid microextraction; MEPS, microextraction by packed sorbent and many others) have also been featured as fundamental and critical step of bio-analytical methods.