Dextran-modified capillaries

Covalent linking of enzyme on fused silica capillaries was also demonstrated by Stigter [119]. Pepsin was covalently immobilized on dextran-modified capillaries as illustrated in Scheme 10.12. The applicability of pepsin-immobilized microreactor was tested with a number of proteins varying in molecular weight, isoelectric point, and sample composition. This open tubular microreactor demonstrated a flow-dependent digestion as represented by native hemoglobin. Complete digestion of... 

Shear dependence of the limiting viscosity nvunber is probably only significant for values of [i ] of several hundred, but this has always to be confirmed. Measurements can be made in a modified capillary viscometer. Details of construction of one for this purpose have been given, and the instrument has been used to study dextran fractions. Shear dependence can also be measured in a rotating cylinder (Couette) viscometer, and a simplified model has been described. ... 

Fluorescein tetramethylrhodamine dextran (FRD) was used as a ratiometric probe, which provides a pH-independent signal (tetramethylrhodamine), to compensate for different organelle volumes, and a pH-dependent signal (fluorescein). The ratio of the pH-independent and pH-dependent fluorescence was expected to provide a quantitative measure of the pH. Acidic organelles (lysosomes and endosomes) were specifically labeled by FRD, because the cells endocytose small amounts of the extracellular medium, which is accumulated in endosomes and eventually lysosomes. CE was performed in a poly((V-acryloyl aminopropanol, AAP) modified capillary to reduce both adsorption at the capillary surface and the electroosmotic flow. LIF detection was performed off-column using a... 

Open tubular capillary microreactor Pepsin Covalent linking Dextran-modified fused silica capillaries with immobilized trypsin Flow dependent digestion observed for native haemoglobin Flow rate [119]... 

Another tyjre of curved srrtfaces can be found within the inner and outer surfaces of cylindrical materials. A widely used application is formd in capillary dectrophoretic separations, in which the irmer walls of fused silica capillaries with micrometer-sized diameters are modified by LbL deposition of various types of polymers and materials to improve or change the separation performance. Examples of such materials are multilayers of PDADMAC and dextran sulfate " dextran sulfate, alginic acid, or hyamronic add and polybrene ... 

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