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A Brief Comparison with
Conventional Beams
 With
our focus on life sciences, Beckman Coulter has developed their
UV-Visible Spectrophotometer around Micro-Focused Beam Technology to
provide the best performance for small volume samples. In addition, we
offer the widest array of accessories and cells to effectively address
the needs of those customers that work with small and precious samples.
The micro-focused beam technology in the DU® Series 600
Spectrophotometers focuses the beam at the center of the cell to a
rectangle of approximately 0.5 x 2.2 mm. This utilizes the entire light
energy for the sample and eliminates any loss of light through masking
by the cell body or any other means. This typically results in lower
noise as compared to systems with a standard beam and, therefore, allows
for wider linear range.
Standard Cell
With standard cells, the entire energy of the standard beam passes
through the sample. Each system on the market performs equally well with
these type of cuvettes.
Semi-Microcell
Depending on the type of semi-microcell used and the standard beam size
of the specific instrument, some energy might be lost. Although masked
semi-microcells can be used with all systems without the need for a
special mask, there might be differences in results.
Small Volume Flow Cell
The energy lost with a standard beam can be significant, depending on
the type of flow cell used. All flow cells are masked and can be used
with all systems without the need for a special mask, although results
from an instrument with micro-focused beam are usually better.
50 µL Microcell
The Beckman Coulter microcell was developed specifically for the
micro-focused beam of the DU Series 600 Spectrophotometers and has
become the standard for measuring small sample volumes. Although another
company is now offering a similar cell, the standard beam of their
instrument needs to be masked to avoid light passing to the detector
above the sample. With the micro-focused beam, no masking is required
and the entire energy passes through the sample.
5 µL Ultra-Microcell
The cell was developed by General Atomics exclusively for Beckman
Coulter and the micro-focused beam of the DU Series 600
Spectrophotometers. After Beckman Coulter gave up the exclusive rights
to this cell, another company started purchasing this capillary
microcell for their instruments. As with the 50 µL microcell, special
masking of the standard beam is required to avoid light passing on the
sides of the capillary to the detector. The micro-focused beam does not
require masking and the entire energy of the beam is utilized for the
sample residing in the capillary.
Micro Sampling Accessories
Beckman Coulter offers a wide range of micro sampling accessories,
specifically designed for the micro-focused beam of the DU Series 600
Spectrophotometers. The applications guide contains descriptions and
pictures of these accessories and cells.
Micro Auto 12 Cell Holder with three four-position 100 µL Multi-Microcells in place
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