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UV/Visible Spectroscopy |
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Written by Administrator
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World's Smallest Fiber Optic Dipping Probe for UV/Visible
Spectroscopy
DipTip™ is a miniature transmission/absorbance
probe for
Microliter spectroscopic sampling.
DipTip's tip diameter is only 1.5 mm -- the size of a 17-gauge needle!
It will fit into all micro centrifuge tubes on the market and is a very
useful tool for measuring protein and DNA samples. The diminutive
dipping probe can also be used for a dissolution system.
Thanks to WPI's proprietary optical design, DipTip is not only four to
five times smaller in diameter than any other product on the market,
but also costs 50% less! Together with our fiber optic-based
spectrophotometers or spectrometer modules (TIDAS I) or CCD
(SPECTRAUSB) and light sources (D2H, and FO-6000TM) microliter samples
can be analyzed very cost effectively. See later in the article for
more information on these WPI products.
To exemplify the performance of the DipTip, Bovine Serum Albumin (BSA)
dissolved in a phosphate buffer BSA has been analyzed with a TIDAS II.
Absorbance spectra and a calibration curve are shown. Each spectra has
been obtained from 50 to 60 µl samples stored in 0.1 mL
centrifuge vials.
Diptip Specifications
| Diptip
Specifications |
DIP-UV |
DIP-NIR |
DIP-UV-SR |
| Tip
diameter |
1.5
mm |
1.5
mm |
1.5
mm |
| Light
pathlength |
2,
5, 10mm |
2,
5, 10mm |
2,
5, 10mm |
| Wavelength
Range (nm) |
230-1000 |
350-1000 |
200-1000 |
| Sample
Volume Required |
20-50
µL |
20-50
µL |
20-50
µL |
| Distance
from tip to upper edge of sample window |
7 mm |
7 mm |
7 mm |
| Total
length (including handle) |
18 cm |
18 cm |
18 cm |
| Fiber
length (from connector to tip) |
1.5 m |
1.5 m |
1.5 m |
| Fiber
Optic Connectors |
SMA
905 |
SMA
905 |
SMA
905 |
| Launch
fibers (2) NA = 0.22 |
400 µm |
400 µm |
400 µm |
| Return
Fiber (1) NA = 0.22 |
400 µm |
400 µm |
400 µm |
WPI offers complete preconfigured systems for a variety of applications
from protein analysis to flow-through colorimetric detection in the
UV-VIS-NIR spectral region. WPI's scientists ensure everything works
together and offers the best results. They have tested each
preconfigured system over many hours in research labs.
TIDAS I is WPI’s high-end spectrometer module designed for
fiber optic based sampling techniques. Using suitable light sources and
sample cells, spectral detection in the wavelength range of 195 to 730
nm can be performed at noise levels as low as 0.8 mAU. TIDAS I
outperforms conventional bench-based spectrophotometers and CCD-based
spectrometer modules, when it comes to high precision fiber optic
sampling.
Using fiber-optic based sample cells and light sources, high-end
detection systems with exceptional sensitivity and noise performance
can be easily assembled. Using our liquid waveguide capillary cells
(LWCC), absorbance based detection system with effective pathlengths as
long as 500 cm and noise levels as low as 0.1 mAU can be achieved at
reasonable cost.
Miniature Spectrometers
WPI offers now its SpectraUSB4 miniature spectrometers optimized for
absorbance, fluorescence and NIR applications. The SpectraUSBs are
miniature spectrometers, which plug directly into the USB port of any
desktop or notebook PC. With the SpectraUSB, getting started is as easy
as installing the Java based SpectraSuite software package and
connecting the spectrometer to the USB port of the computer.
Other features make operating the spectrometer equally hassle-free. The
spectrometer does not require an external power supply; it simply draws
its power from the computer. The SpectraUSB4 spectrometer is pre-set to
a 200-850 nm wavelength range and comes with a UV2-enhanced UV detector
upgrade, a multi-bandpass order-sorting detector coating, along with a
25 µm entrance slit installed for an optical resolution to
1.5 nm (FWHM).
WPI offers different gratings for the spectrometer, which define its
wavelength range. The resolution of the spectrometer is determined by
its slit-width (SLIT-xxx). The miniature spectrometers can be equipped
with a number of detector upgrades. A collection lens (L4) can be
placed in front of the detector array to increase the spectrometers
light collection efficiency and reduce stray light.
This is especially useful when using large core diameter fibers in low
light-level applications. A CCD array with 3648 pixels is used as this
detector UV4 is a detector upgrade, which is required for measuring at
wavelength below 350 nm. Multi-bandpass order sorting filters are
available to avoid second order effects in the spectrometer modules
(OFLV4).
SPECTRAUSB4-NIR is preset to a 350-985 nm range and is equipped with a
25-µm slit. In addition, we offer snap-on, direct attach
accessories specifically designed for these spectrometers. USBVIS and
USBUV are light source/cuvette holder combos for absorbance
measurements in the 390-950 nm for VIS/NIR range and 200-950 nm
UV/VIS/NIR range respectively.
If your application requires a customized spectrometer,
please contact
WPI’s technical department for assistance.
A high-resolution version of the USB4 series is available. The
Spectra4-HR bench can be equipped with all upgrades available for the
SpectraUSB4; contact WPI for customization. For wide wavelength range
applications, WPI now offers a pre-configured high resolution
spectrometer (SPECTRA-HR-CG) with a proprietary composite grating, a 5
µm slit, UV4 upgrade and order-sorting filter to provide a
200-1100nm wavelength range and 1.0nm optical resolution in one
spectrometer.
SPECTRAUSB4-FLG is a pre-configured spectrometer for fluorescence
applications, equipped with a L4 lens and a 200 µm slit.
Integrated into this detector is a time-gated mode that delays the
start of spectral data acquisition by 5-500 microseconds after the
excitation source is turned on. Using a pulsed light source, the
detector sees in this mode the sample when the light is switched off.
However, in order to use the gated phosphorescence mode, the
fluorophore must have a long fluorescence lifetime. Those working with
lanthanides and phosphorescent materials will find the gated
phosphorescence mode particularly useful. To further improve the
efficiency of the detector, the standard mirrors of the optical bench
were replaced by Ag-coated mirrors. This improved the sensitivity of
the detector by over 20%.
Light Sources
WPI also offers several light sources including the D2H, D2LiteTM, and
FO-6000TM. The D2H is a combined deuterium and halogen light source
with integrated TTL shutter for UV/VIS and NIR applications and is
ideally suited to work with WPI's spectrometer modules and sample
cells. For deep UV applications (190 nm), the D2H-2 should be used.
The FO-6000TM is a new miniature tungsten light source that has been
developed for high precision portable and low-power spectroscopy
applications. It was developed to overcome the problem with tungsten
light bulbs and their inherent low light output at wavelengths below
430nm. Its advantage lies in its high light power output, its effective
color temperature of 6000K and its exceptionally low drift below 0.5
mAU/h. The inherent low noise of the FO-6000 makes it particularly
suitable for low-noise detection systems.
The FO-6000FILT inline filter holder directly attaches to the FO-6000
light source. This allows a virtual light loss free insertion of
optical filters with outer diameters from 8 to 25.4 mm and thickness
ranging from 2 to 10 mm into the light path of the FO-6000. With this
filter holder and an optical filter, a highly stable monochromatic
light source can be assembled. These light sources offer a wide
assortment of field applications in environmental and life science as
well as analytical chemistry.
Light Source Comparison Chart
| |
D2H
/ D2H-2 |
FO-6000 |
| Application |
UV/VIS/NIR |
VIS/NIR |
| Spectral
Range |
215/190
- 1700 nm |
380
- 1700 nm |
| Deuterium
lamp life |
1000
hr |
N/A |
| Tungsten/Halogen
lamp life |
1000
hr |
3000*
hr |
| Stability |
<0.5
mAU/h |
<0.5
mAU/h |
| Power
Consumption |
100 W |
6 W |
| Power
requirements |
110/240V,
50-60Hz |
1A
12VDC/1A |
| Shutter/TTL
trigger |
Yes |
Yes |
| Max.
Fiber Output |
1000
mm |
1000
mm |
| Connections |
SMA |
SMA |
| Shipping
Weight |
13.2
lb (6 kg) |
1.3
lb (0.6 kg) |
| Dimensions
(W/H/L) |
5.3
x 5.9 x 12.6 in. (13.5 x 15 x 32 cm) |
4.8
x 2.8 x 7.5 in. (12 x 7 x 19 cm) |
| *Lamp life is dependent upon
internal
power settings. |
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Last Updated ( Monday, 16 May 2011 )
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