SI - Lab on Valve®
Sequential Injection in Lab-On-Valve® (LOV) format is a groundbreaking technology that has won enthusiastic acceptance in the research community for its versatility, and in the routine laboratory for its reliability. The LOV integrates manifold components, including fiber optic-coupled flow through cell, flow through port and microcolumns into a single unit mounted on a multiposition valve.
The advantages of LOV
1) Transparency of flow and optical path
2) Versatility of flow cell design
3) Sample introduction by flow trough port
4) Miniaturization – compact and robust structure
LOV concept achieves downscaling of the SI system through integration of the sampling conduit and of the flow cell into a micromachined compact structure mounted atop a conventional multiposition valve. The Lab-On-Valve® (LOV) system operates in the microliter domain and is compatible with:
UV-VIS spectrophotometry
Fluorescence spectroscopy
Chemiluminescence
Voltammetry
Conductimetry
In contrast to other microfluidic devices, the volume of the sample path within the LOV is minimized by reducing the channel length, while channel diameter is kept wide (0.8mm ID ), in order to prevent system clogging by matrix material often present in “real life” samples.
LOV modules are machined with a very high degree of precision and narrow tolerances
LOV module in Perspex configured for UV-VIS Spectrophotometry
UV-VIS Spectrophotometry
In this configuration the optical fibers are mounted
axially in the flow through cell, using an OO
Spectrophotometer as detector and a Tungsten ,
LED or Deuterium light source. The length of
the light path within the LOV module can be
selected from 1 to 10 mm. By using the cell extension
module the light path can be further increased to 5, 10, 25 and 50 cm.
LOV with light path extended to 25 cm
Fluorescence
For this application the optical fibers are configured at right angles. A suitable combination of excitation sources (LED, Tungsten), and detectors (High Sensitivity OO Spectrophotometer or PMT ) is user selected. Since the flow cell can accommodate an additional optical fiber in the axial direction towards the illuminating fiber, fluorescence and absorbance can be monitored simultaneously.
LOV module configured for fluorescence monitoring
Chemiluminescence
For this application the optical fibers are configured at right angles in order to maximize the volume of the flow cell monitored by optical fibers. Both fibers are connected to the photomultiplier.
Voltammetry and Conductimetry
The LOV flow cell can accommodate up to three
electrodes,making it suitable for voltammetry or
potentiometry with two miniaturized ISE and one
reference electrode...
For details consult the complimentary CD Tutorial
Bead Injection Spectroscopy and
microAffinity Chromatography
Bead Injection (BI), is the third generation of FIA techniques. In its simplest form, microspheres are injected into a conduit, where they are trapped at a selected location. Next, sample zone is injected and perfused through the beads, while sample components react with functional groups on bead surfaces. Retained analyte molecules are detected in their native form by spectroscopy, or reacted in situ with suitable color or fluorescent reagents.
Analyte molecules may also be eluted for detection. Example of such application is microAffinity Chromatography.
For further details consult SI Chromatography or the complimentary CD Tutorial
LOV module configured for
chemiluminescence
LOV module configured for voltammetry
LOV module configured micro
Chromatography
Specifications and Material Compatibility
The Lab-On-Valve ® manifold is compatible with the MicroSIA, FIAlab-3200 and FIAlab-3500 systems.
The Lab on- valve module is offered in Plexiglas ULTEM or PEEK material, and with six or eight ports. Custom designs and materials are available upon request. Plexiglass is suitable for most applications, unless the processed solution does not contain organic solvents or more than 10% ethanol or methanol.
8 port LOV fabricated from ULTEM
Partial Compatibility list for ULTEM:
Acetic Acid, Acetone Alconox Acetone, Alconox , Carbon Tetrachloride, Cellosolve, Chromic Acid, Citric Acid, Clorox, Cyclohexane, Cyclohexylamine, Ethanol, Ethyl Acetate, Ethyl Ether, Formic Acid, Gasoline, Hexane, Hydrochloric Acid, Isopropanol, Kerosene, Lestoll 1, Methanol, Methylethyl Ketone (MEK), Naphtha, Nitric Acid, Phenol, Phosphoric Acid, Potassium Carbonate, Potassium Hydroxide, Propylene Glycol, Skydrol, Sodium Hydroxide, Sulfuric Acid, Tetrachloroethylene, Tin Chloride, Toluene, Trichloroethane (1,1,2-), Triethylphosphate, Xylene, Zinc Chloride
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