Uv 2070/uv Detectors
PRODUCT
PROFILE
UV Detectors
The majority of organic com-
UV spectrophotometer (for
cause sunburn. Of course,
pounds can be analyzed by
variable-wavelength detec-
sunburn results when the
UV–vis detectors, and almost
tion) or photometer (for
amount of exposure to the
70% of published HPLC
single-wavelength detection)
sun or other UV light source
analyses were performed with
equipped with a low-volume
exceeds the ability of the
UV–vis detectors. This fact,
flow-through “cuvette” is
body’s pigment, melanin,
and the relative ease of UV
commonly referred to as a
to protect the skin. Sunburn
detector operation, makes
flow cell. Its job is to detect
in a very light skinned per-
this instrument the most
analytes, which readily
son may occur in less than
useful and most popular
absorb light at the selected
15 min of midday sun expo-
detector for HPLC, and it
wavelength.
sure, while a dark-skinned
has become almost ubiqui-
UV rays are a high-energy
person may tolerate the same
tous in modern laboratories
form of light familiar to most
exposure for hours. The sun-
as part of HPLC systems. A
nonscientists because they
burn process is evidence of
UV interacting with organic
molecules.
Detectors in Space
But UV rays can only be
observed by using special
With a three-year, $300,000
Samples of the gallium
detectors, and the light is
A PerkinElmer HPLC system with
grant from the National Aero-
nitride material already have
difficult to detect because of
UV detector
nautics and Space Administration
been converted successfully
its interactions with soluble
their vibration or rotation
(NASA), scientists at Northwest-
into a camera-like device called
compounds. Beams of UV
of the functional group. The
ern University have developed a
a phototube that is 30% effi-
electromagnetic radiation
intensity of the beam whose
new tool that could lead to a UV
cient, or 6 times better than the
passed through the detector
energy corresponds to the
light detector around 10 times
Hubble’s detectors, but now
flow cell will undergo some
possible transitions decreases
as sensitive as the UV detectors
Ulmer and Wessels are working
change in their intensity
while it is passing through
used on the Hubble Space Tele-
to improve the conductivity of
because of this interaction.
the flow cell. According to
scope. If this apparatus works as
this material to increase its effi-
The measurement of this
the Lambert–Beer law, ab-
scientists hope, it would allow
ciency, as well as improve the
change is the basis of most
sorbance of the radiation is
astronomers to observe impor-
solar blindness of the resulting
optical HPLC detectors.
proportional to the com-
tant objects throughout the
detectors. Ulmer and Wessels
pound concentration in the
universe for the first time. Mel
will work with Oswald Sieg-
cell and the length of the cell.
Ulmer, professor of physics and
mund, associate director of the
Three major regions (IR,
astronomy, and Bruce Wessels,
Space Sciences Laboratory at
visible, and UV) are used in
professor of materials science
the University of California,
spectroscopy. In LC, IR spec-
and engineering, both at North-
Berkeley, to convert samples
trophotometers have found
western, could develop further
of their improved material into
only limited use. There are
a device that is sensitive to UV
phototubes that can then be
Gilson’s 112 UV detector
few transparent polar liquids
rays while naturally insensitive
tested. The resulting detectors,
that can be used as the mobile
to visible and IR light. Current
which require a vacuum to test,
The absorbance of radia-
phase. Spectrophotometers
UV detectors use filters to
work by converting UV light
tion depends on the wave-
working in the 200–600-nm
prevent interference from rays
shining on the material into
length and the functional
range are used widely as LC
with longer wavelengths and,
emitted electrons that are
groups of the chemical com-
detectors.
as a result, are not very sensitive
collected within the photo-
pound. An electromagnetic
An example of UV’s wide
or as efficient as users would
tubes. The electrical signal,
field, depending on its ener-
like. To achieve these properties,
which is proportional to the
gy (frequency), can interact
the device uses gallium nitride,
amount of UV light hitting
with electrons, causing their
KEY TERMS: biotech, envi-
ronmental, LC, MS, pharma-
an advanced semiconductor
the detector, is processed and
excitation and transfer to a
ceutical, separation science,
material.
results in an image.
higher level, or it can excite
spectroscopy
molecular bonds, causing
©2004 AMERICAN CHEMICAL SOCIETY
JULY 2004 TODAY’S CHEMIST AT WORK 49
PRODUCT PROFILE
use is the Gilson 112. Gilson’s
Table 1. Selected UV Detector Manufacturers
112 series UV detector applies
itself through biological sam-
Company
Website
Products
ples, industrial chemicals,
Agilent Technologies
www.agilent.com
1100 series
and small-molecule analysis
Amersham Pharmacia Biotech www.amershambiosciences.com
Monitor UV and Uvicord series
via HPLC.
Bioanalytical Systems
www.bioanalytical.com
UV-116A
A number of companies
Buck Scientific
www.bucksci.com
BLC-20, BLC-70
make non-HPLC UV detec-
Cecil Instruments
www.cecilinstruments.com
Adept CE 4200, 4201
Dionex
www.dionex.com
UVD170U, PDA100
tors. SVT Associates (www.
D-Star Instruments
www.d-star.com
DFL-10, DHS-10, DTS-10
svta.com), for instance, offers
ESA
www.esainc.com
Model 520, 522
its UV-A, UV-B, and UV-C
GBC Scientific Equipment
www.gbcsci.com
LC 1200, 1205, 1210
detectors, whose applications
Gilson
www.gilson.com
112, 15X
include UV curing and
Jasco
www.jascoinc.com
UV-2070, 2075, 2077
drying, combustion moni-
JMST Systems
www.hyperquan.com
VUV-14, VUV-14D, VUV-24, VUV-25, VUV-26
toring, arc detection, pho-
Michrom BioResources
www.michrom.com
MAGIC, Paradigm MD1, MD2
Micro-Tech Scientific
www.micro-tech.us
VUV202, Linear MT 200/200CE, MT201, MT205
totherapy, sterilization
PerkinElmer
www.perkinelmer.com
785A, LC295, Series 200
control, spectroscopy, bio-
Polymer Laboratories
www.polymerlabs.com
PL-LC1200
logical agent detection, solar
Shimadzu www.shimadzu.com
SPD-10AVP/10AVVP
irradiance measurement,
Spectrum Chromatography
www.lplc.com
Spectra/Chrom Model 280
industrial process monitor-
For a more extensive list, visit www.labguideonline.com.
ing, and missile or artillery
fire detection. The BioQuest
from Bioscan (www.bioscan.
ed standard in the instru-
ed or exported to a PC.
while controlling mobile
com) has the normal func-
ment’s on-board software.
Another useful product is
phase, injector, column, and
tions of UV–vis spectropho-
Data are displayed on a 4-in.
the Michrom BioResources
UV flow-cell temperature
tometers, including scanning,
LCD screen and can be print-
MAGIC (Micro Analytical
from ambient to 60 °C.
time course plots, single-
Gradient Integrated
Other companies that
wavelength measurements
Chromatograph),
produce UV detectors for
in absorbance, concentration,
which is versatile in
HPLC include PerkinElmer,
or transmittance, cell and
HPLC and LC/MS
Jasco, Amersham Pharmacia
wavelength programming,
separations. Its
Biotech (now GE Health-
concentration curve fitting,
column oven will
care), Micro-Tech Scientific,
method storage, and so on.
accommodate
ESA, and Shimadzu, to name
Pre-programmed methods
columns from 50 µm
just a few.
for protein analyses and
to 10 mm i.d. and 10
Felicia M. Willis and
nucleic acid assays are provid-
A JMST UV-Vis monitor for LC
to 250 mm in length,
Michael J. Felton ◆
50 TODAY’S CHEMIST AT WORK JULY 2004
www.tcawonline.org
