Protein & Nucleic Acid Analysis
Ocean Optics offers spectrometers and accessories supporting a variety of sensing techniques for protein and nucleic acid analysis, including UV-Vis and NIR spectroscopy, Raman analysis and fluorescence. Our modular approach allows users to select from detector, optical bench and accessory options to configure systems for a wide range of applications.
Systems can be configured for a range of OEM and laboratory measurement needs, with applications such as DNA, RNA and protein determination among the options. The flexibility of our spectrometers and accessories allows users to switch easily among techniques such as absorbance and fluorescence.
Featured:
STS-UV Microspectrometer
Compact yet powerful spectrometer is ideal for UV-Vis absorbance analysis of biological molecules.
Example Setup: Fluorescence of Biological Samples
Overview
Fluorescence measurements require a sensitive detector and an effective filter for discriminating between powerful excitation source wavelengths and weak emissions from the sample. For analysis of biological samples such as proteins, the amount of fluorescence can often give the researcher insight into the protein’s conformational states or activity under different biological conditions including changes in temperature, pH and ion concentration.
Fluorescence System Setup
We offer several spectrometers useful for fluorescence, but recommend the high-sensitivity, preconfigured QE Pro-FL for most fluorescence applications. The QE Pro-FL is set to ~350-1100 nm and is configured with a 200 µm slit and variable longpass filter.
In this setup, we use an LLS series UV LED for excitation. Nearly 20 different UV wavelength options are available, starting at 240 nm. The PX-2 pulsed xenon source is also useful for excitation.
Sampling Considerations
For solutions sampling, we use a CUV-ALL-UV 4-way cuvette holder, with the fibers coupled at 90 degrees to each other; 74-MSP mirrored screw plus to improve sensitivity; and two QP600-2-SR solarization-resistant optical fibers. Quartz cuvettes (1 cm pathlength) are used for the sample. Temperature-controlled cuvette holders are also available.
For most fluorescence experiments, you’ll need a filter to discriminate between excitation source wavelengths and spectral emissions from the sample. Our Linear Variable Filters are excellent for shaping the excitation energy from broadband sources. With a narrow-band excitation source such as an LED, a filter may not be necessary.
OceanView software completes the system.
Fluorescence System Components
The setup described here is just one of several options available for fluorescence measurement of solutions. For fluorescence of solids, one would likely select a broadband excitation source and a reflection/backscattering probe in place of the LED-cuvette holder setup described here.
Here are the items in the example setup:
| QE Pro-FL | High sensitivity, back thinned CCD spectrometer is preconfigured for fluorescence with 200 µm slit and order sorting filter |
| LLS-xxx | LED for excitation is available in multiple UV wavelength options |
| CUV-ALL-UV | 4-way cuvette holder for 1 cm pathlength cuvettes |
| 74-MSP | Mirror screw plugs for redirecting energy in the cuvette holder |
| QP600-2-SR | 600 µm optical fiber, solarization resistant, 2 m length |
| CVFL-Q-10 | Quartz cuvette, 1 cm pathlength, for fluorescence |
| OceanView | Spectroscopy software |
Also Notable
Ocean Optics provides the modular optical sensing solutions and applications know-how to help you solve your measurement problems with a great degree of flexibility. For example, when analyzing proteins, users can take advantage of our QE series spectrometer’s replaceable slit design to perform both fluorescence and absorbance measurements. Similarly, our 4-way cuvette holder can be positioned for both 90 degree (fluorescence) and straight-through (absorbance) measurements. This modular approach is not typically available in traditional lab instrumentation.
Absorbance characteristics of various proteins found in red blood cells.
Fluorescence spectra of Bovine Serum Albumin reveal changes in protein structure with exposure to a low-pH buffer.
Fluorescence measurements reveal lysozyme protein conformation changes.
Absorbance of NADH samples with quinine sulfate for comparison.
