|
Description:
|
The current trend of separation science is towards miniaturization . Micro separations such as microcolumn liquid chromatography (Micro LC ) and capillary electrophoresis have gained considerable importance over the past decade . The early developments of Micro LC were mainly due to the efforts of Horvath and coworkers [1 ,2] , Ishii et al . [3 , 4] , Scott and Kucera [5 , 6] , and Novotny et al . [7 , 8] . Since then , the field of Micro LC has been steadily growing . Higher column efficiencies , lower mobile phase flow rates , less consumption of mobile and stationary phases , and increased mass sensitivity due to smaller peak volumes are some of the appealing advantages of Micro LC [9 , 10] . Also , Micro LC is ideal for the analysis of complex sample mixtures such as exotic physiological fluids and the contents of a single cell [11 ,12] .
In order to maintain the separation efficiency obtained from Micro LC , extra -column volume in injection , detection and connection systems should be minimized [10] . While injectors are commercially available to inject appropriately small amounts of sample (60 - 100 nL ) , connecting tubing should be minimized wherever possible in order to reduce the extra -column broadening . The maximum permissible detector volume for a 250 |im I .D . column packed with 5 |im particles is 400 nL [10] . Smaller capillaries demand even lower detector volumes . |