Polystyrene glass bead filled

Immunochemical analysis is a fast developing field with numerous possibilities for further improvement. Much effort is being put into the development of continuous measurements, such as flow-injection immunoanalysis (FI I A) and immunosensors. A quasicontinuous FI IA of pesticides was developed by Kramer and Schmid ) on the basis of a competitive lA. Here, the Abs are immobilized on a membrane. The reaction takes place in the membrane reactor, the central part of the flow injection system. All reagents are sequentially added to the reactor and the product is assayed with the aid of a fiow fiuorimeter. The measuring range of the fiow injection analysis almost equals that of the EIA. Wittmann and Schmid used an Ab column reactor filled with polystyrene or glass beads with the Ab immobilized via the avidin/biotin system. This system showed a stable Ab activity for a minimum of 500... 

A glass slide was successively dipped into a 10 mM n-octadecyltrichlorosilane/ benzene solution for 8 h and a 500 fi ml anti-CEA/phosphate buffer solution for 2 h. Onto the substrate we drew lines at intervals of 30 [im with a glass capillary (tip radius, 5 pm) filled with a 2.0 pg/ml CEA/phosphate buffer solution. The substrate was then washed thoroughly with water. Polystyrene beads (Kodak, diameter 10 pm) adsorbing anti-CEA were prepared by soaking the bear beads into a 500 pg/ml anti-CEA /phosphate buffer solution for 2 h, followed by washing three times in a 0.1 M phosphate buffer solution. The anti-CEA adsorbed polystyrene beads/phosphate buffer solution was dispersed on the CEA patterned substrate. The bead-adsorbed substrate was gently washed with water. 

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