|
|
The manual handling of solutions (known as "beaker
chemistry") remains the Achilles Heel of modern analytical instrumentation.
It is currently being replaced by flow injection analysis (FIA), which is
computer compatible and allows automated handling of sample and reagent
solutions with a strict control of reaction conditions. FIA was first described
in Denmark by Ruzicka and Hansen in 1975. Since then the technique has
grown into a discipline covered by six monographs and more than 15,000 research
papers. The scope of the method grew from serial assay of samples to a tool for
enhancement of performance of spectroscopic and electrochemical instruments.
Most recently FI became applied in biology for study of live cells by
fluorescence microscopy and flow cytometry. Other fields include
monitoring of chemical processes in real time, biotechnology, immunoassays
including antibody/antigen reactions.
 |
Flow Injection Analysis |
Flow Injection Continuous Flow
|
|
Flow Injection Analysis (FIA), the first generation of
FIA techniques, is also probably the most widely utilized. In its simplest
form, the sample zone is injected into a flowing carrier stream of reagent.
As the injected zone moves downstream, the sample solution disperses into
the reagent, causing the product to form. A flow through detector placed
downstream records the desired physical parameter such as colorimetric
absorbance or fluorescence.
The modern Flow Injection Analysis system usually consists of a high quality
multichannel peristaltic pump, an injection valve, a coiled reactor, a
detector such as a photometric flow cell, and an autosampler. Additional
components may include a flow through heater to increase the speed of
chemical reactions, columns for sample reduction, debubblers, and filters
for particulate removal.
The typical FIA flow rate is one milliliter per minute, typical sample
volume consumption is 100 microliters per sample, and typical sampling
frequency is two samples per minute. FIA assays usually result in sample
concentration accuracies of a few percent. |
FIA Lab-On-Valve
The FIA
Lab-On-Valve® integrates all connections,
sample loop, and flow cell into one simple manifold. No need to
purchase separate expensive manifolds for each type of assay.
Please visit our
Agricultural and Environmental Testing page for
discussions of specific applications for FIA. |
 The
Second Generation - Sequential Injection Analysis
Sequential Injection
Analysis
Sequential Injection Analysis (SIA) is the second generation approach to
FIA compatible assays. SIA usually consists of a single-channel high
precision bi-directional pump, a holding coil, a multiposition valve,
and a flow through detector. The system is initially filled with a
carrier stream into which a zone of sample and a zone of reagent(s) are
sequentially aspirated into a holding coil, forming a linear stack.
These zones become overlapped due the parabolic profile induced by
differences between flow velocities of adjacent streamlines. Flow
reversals and flow acceleration further promote mixing. The
multiposition valve is then switched to the detector position, and the
flow direction is reversed, propelling the sample/reagent zones through
the flow cell.
SIA only uses a small fraction of sample and reagent(s) when compared to
FIA, and consequentially produces far less waste.
Typical reagent consumption is only around 20-30 microliters per assay.
This often makes SIA the best choice for remote site and online process
monitoring.
|
SIA Lab-On-Valve®
SIA in
Lab-On-Valve® (LOV)
format is a groundbreaking technology that has won
an enthusiastic acceptance in the research community for its
versatility, and in the routine laboratory for its reliability. The LOV
integrates manifold components, including a fiber optic coupled flow
through cell, into a single unit mounted on a multiposition valve.
The SIA LOV is used as a platform for
microSequential Injection as well as for Bead Injection and Sequential
Injection Affinity Chromatography. Please visit our
Biomolecular Assays
page for additional
discussions on these applications.
MPG Movie Clip
demonstrates the ease at which microbeads are
manipulated from holding port to optical flowcell, all within the LOV
manifold. (4 MB long, may take a minute or so to download).
|
Additional
Information (Publications, Conferences)
|
Please email or phone FIAlab Instruments
for additional product information.
Email:
fialab@flowinjection.com,
Voice: 425-376-0450 or 1-800-963-1101,
Fax: 425-376-0451
|
|
|
|