Analytical techniques delivery systems

The basic SFC system comprises a mobile phase delivery system, an injector (as in HPLC), oven, restrictor, detector and a control/data system. In SFC the mobile phase is supplied to the LC pump where the pressure of the fluid is raised above the critical pressure. Pressure control is the primary variable in SFC. In SFC temperature is also important, but more as a supplementary parameter to pressure programming. Samples are introduced into the fluid stream via an LC injection valve and separated on a column placed in a GC oven thermostatted above the critical temperature of the mobile phase. A postcolumn restrictor ensures that the fluid is maintained above its critical pressure throughout the separation process. Detectors positioned either before or after the postcolumn restrictor monitor analytes eluting from the column. The key feature differentiating SFC from conventional techniques is the use of the significantly elevated pressure at the column outlet. This allows not only to use mobile phases that are either impossible or impractical under conventional LC and GC conditions but also to use more ordinary... 

Flame ionisation detector and specific detector systems. TLC and HPTLC are fast and versatile analytical techniques and considerable time and energy has been expended to automate the various operational stages. In recent years there have been significant advances in the areas of sample application, solvent delivery, documentation and quantitation. 

In the pharmaceutical field, MEs belong to the group of colloidal drug delivery systems and can therefore be subjected to several physicochemical analytical techniques used to characterize conventional colloids. MEs can be differentiated from coarse emulsions or other two-phase systems by visual inspection (ME = transparent or translucent, two-phase systems = turbid). Visual inspection is therefore... 

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