Serial concentration gradient

Mixer 90 [M 90] Serial-diffusion Micro Mixer for Concentration Gradients... 

Mixer type Serial-diffusion mixer for concentration gradients Channel depth at dam structure 5 pm... 

It is the versatility of FIA that is the decisive factor behind the widespread application of the technique. Replacement of the established practice of homogeneous mixing by the exploitation of concentration gradients, well defined in time and space, has provided a new approach to solution handling and information gathering on chemical systems. It allows the use of numerous detectors, incorporation of a variety of separation techniques, and miniaturization of the apparatus so that serial assays may be performed in microscale, on small sample volumes and with limited reagent consumption. Such an enclosed, miniaturized automated instrumental technique contributes to improvement of the working environment. 

K. M. Maness, R. H. Terrill, T. J. Meyer, R. W. Murray, R. M. Wightman, Solid-state diode-like chemiluminescence based on serial, immobilized concentration gradients in mixed-valent poly[Ru(vbpy)(3)](PFg)(2) Ulrns, Journal of the American Chemical Society 1996, 118, 10609. 

Polarization by constrictivity of pores results from the effect that pore space is characterized by an alternating change of wide pore bodies and narrow pore throats. Pore space builds up a serial cormection of active (ion-selective) and passive (non-selective) zones. The zones have different cation and anion transport numbers, which produce local concentration gradients under an external electrical field. The electrical current flow therefore results in a deficiency of anions and surplus of cations at the boundaries of the thick and thin capillaries. 

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