Heterogeneous flow injection system

Heterogeneous Flow Injection System (Indirect Method).261... 

Nandakumar, M. P., and Mattiasson, B. (1999). Binding assays in heterogeneous media using a flow injection system with an expanded micro-bed adsorption column. Bioseparation 8, 237-245. 

J.J. Harrow, J. Janata, Heterogeneous samples in flow-injection systems part. 2. standard addition, Anal. Chim. Acta 174 (1985) 123. 

Immunoassay is a very sensitive technique that can be applied in environmental chemistry and food chemistry, and is very often used in clinical chemistry. By inclusion of immunoassay in the flow injection system, precise control of reaction times can be achieved compatibility with any heterogeneous or homogeneous format, and detector, good accuracy, and reproducibility are assured the analysis time decreases and the analytical process becomes more flexible.243... 

J. J. Harrow and J. Janata, Heterogeneous Samples in Flow-Injection Systems. Part J. Whole Blood. Anal. Chim. Acta, 174 (1985) 115. 

Ruzicka, J., Hansen, E. H., Homogenous and Heterogeneous Systems, Flow Injection Analysis Today and Tomorrow , Anal. Chim. Acta 214 (1988) 1-27. 

In this study two different flow-injection immunoassays are presented as well as the flexible automation system CAFCA (Computer Assisted Flow Control Analysis), which has been used for their control, uptake measurement, evaluation and visualization. Both immunoassays (a heterogeneous and a homogeneous assay) are based on the principles of flow-injection analysis and were developed for reliable, fast monitoring of relevant proteins in animal cell cultivation processes. Off-line applications of measurements of medium samples as well as online application during a mammalian cell cultivation are presented. All results are compared to results obtained with ELISA (Enzyme Linked Immunosorbend Assay). The requirements of the automation of flow-injection immunoassays with respect to their flexible control are discussed. 

New immunoassay concepts were described in which immobilized affinity ligands are used in unique flow-through systems (flow-injection immunoassay, FIIA). These systems are exclusively heterogeneous. Both immobilization of a specific antibody or a hapten on the solid support is possible. In most cases the scheme of the assay used is based on a sequential competitive enzyme immu-noas.say procedure [66], [67],... 

Beads packed in microcolumns is the most reported in literature, since users can customize the quantity of resin according to the capacity of it, to the volume of sample to be loaded, and to the minimum detectable activity (MDA) of the detector used. In general, packing is manually replaced in flow systems based on flow injection analysis G A), sequential injection analysis (SIA), multisyringe flow injection analysis (MSFIA) and multipumping flow systems (MPFS). By the contrary, lab on valve (LOV) allows the manipulation of heterogeneous solutions, i.e. bead injection, achieving the automated replacement of the resin. In Chapter 3 are described in detail the parts of the microcolumns and the way to fill them. Table 8.1 summarizes the variety of available resins from TrisKem International [4]. 

System failure for in situ bioremediation efforts is often the result of ineffective transport of nutrients and electron acceptors due to channeling into preferential flow paths, heterogeneities, adsorption, biological utilization, and/or chemical reactions in the soil. Many of these problems can be overcome using electric fields for transport and injection instead of conventional groundwater injection by hydraulic techniques. 

The experimental flow system is taken to be a rectangular parallelepiped of dimensions z, , z2o, and z3 , with a known porosity experimental domain. A fluid is introduced at the injection or entrance face Sent, located at z = 0, at a constant flow rate that is assumed to be known. The fluid, on average, flows through the medium in the positive z, direction, although local heterogeneities in the sample will cause the velocity field to vary in both the z2 and z3 directions. No fluid is allowed to enter or leave the porous matrix through the sides, Snf, and all of the fluid is even-... 

---