RIAC A Recycling Immunoaffinity Chromatograph Instrument

1
RIAC A Recycling Immunoaffinity Chromatograph
Instrument
Recycling immunoaffinity chromatography (RIAC)
for multiple analyte analysis has been used by a
number of researchers and the basic design is
well described by Phillips et. al.(1). This
procedure is based on the serial perfusion of a
pre-labeled (e.g. fluorophore) sample through a
battery of small immunoaffinity columns as shown
in figure 1. Each immunoaffinity column has an
immobilized antibody design to isolate a specific
bio-analyte from the crude biological sample
complex. These columns are re-perfused with
buffer in a serial fashion to remove any weak
nonspecific binding that may have occurred.
Activation of the 3-way solenoid valves allows
the user to isolate any single column for sample
elution as shown in figure 2. Typically, acid
elution of the bound analyte will release the
captured molecules and carry them off to a
detector. Analytes with a fluorochrome label can
be detected with Laser-Induce-Fluorescence (LIF),
which is very sensitive to ultra low quantities
of labeled analyte.
Figure 1 Conventional RIAC, as presented by
T.M. Phillips et. al (9)
Figure 2 Conventional RIAC setup for analyte
elution
(1) Phillips TM, Krum JM Recycling immunoaffinity
chromatography for multiple analyte analysis in
biological samples J CHROMATOGR B 715 (1) 55-63
SEP 11 1998
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The FIAlab SI-RIAC Approach
The approach taken by FIAlab is radically
different to the traditional RIAC approach
presented on the previous slide. The unique
feature of this system is FIAlabs RIAC valve,
which combines the ability to pass sample through
multiple columns in series, with the ability to
select individual columns for analyte elution.
As a consequence, this single RIAC valve replaces
the need for the bank of twenty 3-way solenoid
valves used in the conventional 10-column RIAC
layout. Researchers can easily modify the
immunoaffinity column packing, and any number of
columns (10 or less) can be used to perform
multi-analyte assay. The intelligent fluidic
design allows the FIAlab RIAC to run using
low-pressure hydrodynamic flow, allowing
expensive HPLC pumps to be replaced by precision
syringe pumps.   The FIAlab RIAC system also
incorporates a built in Laser Induced Fluorometer.
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The FIAlab SI-RIAC Valve Design
RIAC Column Valve Schematic depicting
sample/carrier flowing through all columns in
series. Note two-way valve set in left
position. Paths in column valve colored red are
part of router (rotates with valve position
change). Black port is blocked.
RIAC Column Valve Schematic depicting
reagent/carrier flowing through only column 2
(for example). Note two-way valve set in right
position.
Note Above diagrams are simplified to four
columns, standard FIAlab SI-RIAC valve has ten
columns