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Double-beam flying spot scanner for two-dimensional polyacrylamide gel electrophoresis
Analytical Biochemistry
|May 15, 1985
Summary
A novel double-beam photometer utilizes a cathode ray oscilloscope (CRT) as its light source. This innovative system enables direct absorbance measurement with linear results across a wide dynamic range.
Area of Science:
- Analytical Chemistry
- Optical Instrumentation
- Biophysics
Background:
- Traditional photometers often rely on conventional light sources.
- Developing cost-effective and versatile spectrophotometric tools is crucial for various scientific disciplines.
Purpose of the Study:
- To describe the construction and functionality of a unique double-beam photometer.
- To demonstrate the use of a cathode ray oscilloscope (CRT) as a light source for absorbance measurements.
Main Methods:
- A CRT light source was focused to a small spot (<0.15 mm) for precise scanning.
- The light beam was split into sample and reference paths, detected by photomultipliers.
- A logging amplifier converted detector signals to absorbance, controlled by a 16-bit computer interface.
Main Results:
- Linear absorbance measurements (0-2) were achieved, extendable to 3 with neutral filters.
- The system generated a 256x256 pixel image in approximately 5 minutes.
- Scanning speed was dependent on CRT phosphor persistence (P4), with faster options available (A6 phosphor).
Conclusions:
- The CRT-based photometer offers a viable and adaptable method for absorbance spectroscopy.
- This system provides a cost-effective alternative for applications requiring precise optical measurements.
- Further optimization with different phosphors can enhance scanning speed and system performance.
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