Advantages comparison with other separation techniques

In comparison to other electrophoretic techniques moving boundary electrophoresis has only Umited applications and can be used for testing, among other things, purity of substances. Its advantage is based on the fact that rather simple equipment can be used (in comparison with isotachophoretic apparatus) zone boundaries are detected with a conductivity and a photometric detector and the whole separation is carried in narrow bore tubes. 

Coupling FFF with other techniques can enhance measurement capabilities. Here, the possibility of taking fractions after the FFF separation is of great advantage. The use of photon correlation spectroscopy, for example, to determine the size of spheres eluted from sedimentation FFF yields both size and density [75]. Further comparison can be achieved with electron microscopy. In principle, every analytical technique (spectroscopy, microscopy, chemical analysis, etc.) can be performed off-line on fractions from FFF. 

Calibration and quantification procedures are easier in LA-ICP-MS compared to other solid-state mass spectrometric techniques because the laser ablation and the ICP ion source operate at normal pressure and the laser ablation of solid samples and ionization of analytes are separated in space and time. Therefore the advantage of solution calibration in ICP-MS can be applied in this solid-state analytical technique. The introduction of solution based calibration, which is only possible in LA-ICP-MS, was an innovative step in the development of this sensitive mass spectrometric technique. A number of different calibration approaches using aqueous standard solutions in the dual gas flow technique have been discussed by various authors.74 75 In the dual gas flow injection technique , the nebulized standard solution and the laser ablated sample material are mixed in the -piece and the two gas flows from the nebulizer (e.g. ultrasonic nebulizer) and laser ablation chamber are added. Using solution based calibration with the addition of a standard solution, Leach et alP determined minor elements in steel reference materials with a relative accuracy of a few %. In comparison to the so-called dual gas flow technique proposed in the literature, where the argon flow rates through the nebulizer and ablation cell add up to 11 min-1 (e.g. 0.451 min-1 and... 

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