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Flame
Atomic
Absorption/Emission Spectrometer
Atomic spectrometers are
mostly used to measure metal concentrations in solution.
Solutions are aspirated into a flame, where thermal energy atomizes the sample.
The metal of interest emits or absorbs (from an element specific lamp focused through the
flame) specific wavelengths of light. The radiant power absorbed or
emitted at various concentrations allow the determination
of metals in complex samples such as lead in infant blood, arsenic in soil, or
manganese in water. |
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Gas
Chromatograph Gas chromatography is
typically used to separate, identify, and/or quantify volatile compounds of a
mixture.
A carrier gas passes through a 2-50 meter tube (column), which is either packed or coated
with specifically designed and chosen materials. Solutions are volatilized by
syringe-injection into a heated zone, combined with carrier gas, and swept
into the separation column. Substances with strong affinity for the column
material take longer to pass through than those
with weaker affinity, resulting in a separation of the mixture.
Programming the column's oven temperature can enhance the
separation. Placing a detection device at the end of the column allows the identification
and quantification of the bands or peaks as they elute from the column.
Non-volatile or thermally sensitive compounds are generally separated by
liquid chromatography. |
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Gas
Chromatograph-Mass Spectrometer
A
GC-MS system combines the volatile compound separation technology of GC with the
structure determination power of mass spectrometry, resulting in a single
technique for separation, quantification, and identification of components in a volatile mixture.
GC column effluents are
typically fed into an ionization chamber and bombarded with high energy electrons
in order to ionize and fragment the
mixture components as each elutes. Ions are directed to a
detection system through a mass
selector, which is quickly scanned through a mass range producing a graphical
plot of
ion intensity vs. mass/charge ratio, as well as a plot of total ion vs. time.
The total ion chromatogram peak area can be used to determine the amount a component
present, while mass spectra contains molecular and fragment ion patterns
that can help identify the substance. The data collection workstation contains a mass
spectral library of over 50,000 compounds that can be used for comparison.
Drug testing at the Olympics is usually done by GC-MS. |
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Gas
Chromatograph-Ion Trap Mass Spectrometer
As with other
GC-MS systems, an ion trap GC-MS system combines the volatile compound separation technology of GC with the
structure determination power of mass spectrometry, resulting in a single
technique for separation, quantification, and identification of components in a volatile mixture.
Additionally, the ion trap allows the formation of gaseous anions and cations
that can be confined by the electric and/or magnetic fields for an extended
period of time. The trapping and re-fragmenting of these ions can
provide additional information about the structure of the compound of
interest. |
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Inductively
Coupled Plasma Atomic Emission Spectrometer
An inductively
coupled plasma atomic emission spectrometer is generally used to provide
qualitative and quantitative information about metals in solution samples.
Using an inert, inductively heated, high temperature environment, efficient
atomization and spectral emission by the elements of interest is generally
observed when compared with other atomization techniques. Combining the
plasma with an echelle monochromator and two dimensional array charge injection device
detection system makes the determination of many elements simultaneously possible.
The axial orientation of the plasma provides limits of detection generally an
order of magnitude lower than radially oriented plasmas. The
computer workstation's spectral library aids in the identification of metals in
unknown samples. |
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Fourier
Transform Infrared Spectrometer Infrared
spectroscopy is typically used to provide structural information about a
substance of interest. The substance is exposed to a range of infrared
frequencies resulting in a graphical plot of radiant power absorbed (or
transmitted) vs. frequency, wavelength, or wavenumber. FT-IRs are equipped with a Michelson interferometer
in order to simultaneously measure
all infrared frequencies passing through a sample. The resulting
interferogram is deconvoluted by a Fourier analysis. The resulting
spectrum is a useful molecular fingerprint often employed
by forensic labs to analyze fibers, paint chips, or countless other types
of samples in solid, liquid, or gaseous form. The data collection
workstation contains an infrared spectral library of over 50,000 compounds
that can be used for comparison. |
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Polarimeter Enantiomeric
compounds (optical isomers) are identical in almost all of their physical and
chemical properties. One notable exception is the direction of rotation
of the plane of vibration of plane-polarized light. Plane polarized
light is light in which all wave vibrations have been filtered out except for
those in one plane. The polarimeter is used to polarize light and then
show the angle of rotation of the plane of vibration by the optically active
compound placed in the light path. The amount of rotation depends on the
structure of the molecule, temperature wavelength and concentration.
Polarimeters can be used to follow the course of reactions between chiral
compounds. |
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UV/Vis
Diode Array Spectrophotometer UV/Vis spectrophotometry is typically
used to provide quantitative or structural information about a
substance. Samples are generally placed in a small cuvette and exposed
to ultraviolet and visible light. The frequencies of unabsorbed light
are dispersed and directed onto a detection system constructed with a linear array of
light sensitive diodes. This array
allows the instantaneous measurement of the complete UV/Vis spectrum, rather
than monitoring a single frequency. The computer workstation allows for
timed events to be monitored. An important use of diode array instruments
is to study enzyme kinetics. |
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UV/Vis Scanning Spectrophotometer UV/Vis spectrophotometry is typically
used to provide quantitative or structural information about a
substance. Samples are generally placed in a small cuvette and exposed
to ultraviolet and/or visible light. The frequencies of unabsorbed light
are focused onto a photomultiplier tube detection system using a double beam
design. Spectral bandwidths of 0.25 nm are possible. Timed
measurements are possible at fixed wavelengths for kinetic studies. |
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Spectrofluorometer
Fluorescence involves the absorption of light, from a light source, by a
substance, followed rapidly by an
emission of light, at a lower frequency, by the substance. Relatively few
substance exhibit this phenomenon making fluorescence a highly selective
technique. Fluorescence is typically observed instrumentally at a right
angle to the excitation light source resulting in a highly sensitive
technique. Fluorescence is the detection technique commonly used in
protein and DNA sequencing, and in the
detection of many environmental pollutants. |
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NMR Spectrometer
Nuclear Magnetic Resonance
spectroscopy is probably the most important technique used today for the
structural study of organic and inorganic compounds. Substances are placed into a large magnetic
field (commonly a superconducting magnet using a wire coil cooled to 4
K in a reservoir of liquid helium). The spinning nucleus of an atom either
aligns
with or against the externally applied magnetic field. Radio frequency
radiation is used to "flip" the nuclear spin. The frequency
absorbed by a nucleus is determined by the local electron density near each nucleus and
by the geometry of the molecule. NMR spectra are used to determine
protein structure and for countless other applications. |
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High
Performance Liquid Chromatograph Liquid
chromatography is
typically used to separate, identify, and/or quantify compounds in a mixture.
A carrier solution (mobile phase) is forced by means of a pump, through a 10-30
centimeter tube, or column, which is packed with a
specifically designed and chosen material. Mixture solutions are
syringe-injected into the mobile phase and carried into the separation column. Substances with strong affinity for the
packing
material take longer to pass through than those
with weaker affinity, resulting in a separation of the mixture. The mobile
phase can be held in a fixed composition (isocratic mode) or varied to enhance
the separation by using multiple pumps and a controller (gradient elution
mode). Placing a detection device at the end of the column allows the identification
and quantification of the bands or peaks as they elute from the column.
HPLC is an important technique for the pharmaceutical industry, used to determine the purity of medications and to quantify therapeutic
components. It is also widely used in the flavor and environmental
industries. Volatile mixtures are commonly analyzed by gas chromatography. |
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Ion Chromatograph
Ion chromatography is a form of liquid chromatography in which the substances
of interest usually carry a formal charge. The column packing material
contains ionic sites, that have an attraction for oppositely charged . These sites serve as ion exchangers.
Ions are separated based on their charge and size. Ion chromatography is
a widely used technique for the analysis of ions in environmental samples. |
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Electrochemical
Analyzer
(BAS100A)
Electrochemical analysis is a widely used technique for analyzing substances
in our bodies that can be easily reduced or oxidized. Since many
biochemical processes involve redox reactions, there are many useful applications
of these techniques. Electrochemical analysis is also useful for
the trace detection of metals. |
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Inert
Atmosphere Glove Box
The inert atmosphere glove box, or sometimes "dry box", is
used for the synthesis, storage and manipulation of air or moisture
sensitive materials. The workspace is typically filled with nitrogen, argon or other inert gas providing a dry, air free environment. Arm-length gloves and viewing window provide a means
of working with materials inside the chamber. An antechamber, which can be evacuated or flooded with inert gas allows introducing materials or
equipment from the room into the inert atmosphere. Glove boxes have a central and indispensable role in the study of air-sensitive compounds. |
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Protein
Perfusion Chromatograph
Protein perfusion chromatography is an advanced technique for the rapid
separation of proteins. Samples pass through small beads that have
pores specially designed for protein separation. Effluents are collected
and repurified. This instrument is used to separate cell components
to obtain pure protein samples for crystallization and for structure determination
with X-Ray diffraction. |
