Protein quantitation device

A device for measuring absorption of infrared radiation by a sample, the device comprising:

• a source of infrared radiation;
• a sample holder positioned to place a sample in a location to receive infrared radiation from the source;
• a first Fabry-Perot interferometer positioned to receive infrared radiation originating from the source and passing through the sample, the first Fabry-Perot interferometer comprising a pair of spaced-apart reflective surfaces, at least one of which is movable to change the spacing between the reflective surfaces;
• a first detector positioned to receive infrared radiation from the first Fabry-Perot interferometer and to produce an output signal indicating the intensity of the infrared radiation received at the first detector;
• a first band pass optical filter positioned in an optical path of the device such that infrared radiation from the source passes through the first band pass optical filter before reaching the first detector, the first band pass optical filter passing a first band of infrared radiation wavelengths;
• a second Fabry-Perot interferometer positioned to receive infrared radiation originating from the source and passing through the sample, the second Fabry-Perot interferometer comprising a pair of spaced-apart reflective surfaces, at least one of which is movable to change the spacing between the reflective surfaces;
• a second detector positioned to receive infrared radiation from the second Fabry-Perot interferometer and to produce an output signal indicating the intensity of the infrared radiation received at the second detector;
• a second band pass optical filter positioned in an optical path of the device such that infrared radiation from the source passes through the second band pass optical filter before reaching the second detector, the second band pass optical filter passing a second band of infrared radiation wavelengths different from the first;
• and
• a controller coupled to the source, the first and second Fabry-Perot interferometers, and the first and second detectors, the controller including a processor programmed to:
• cause each of the first and second Fabry-Perot interferometers to be tuned to a respective series of different resonant wavelengths;
• receive the output signals of the respective detectors at each of the series of resonant wavelengths;
• and
• record an absorbance spectrum indicating the absorbance of the sample as a function of infrared radiation wavelength within the range of wavelengths passed by the first and second band pass optical filters.

A method of protein quantitation, the method comprising:

• directing infrared radiation to a sample from an infrared radiation source, at least some of the infrared radiation passing through the sample;
• directing infrared radiation having passed through the sample to a first band pass optical filter and to an input aperture of a Fabry-Perot interferometer;
• causing the Fabry-Perot interferometer to be tuned to a series of different resonant wavelengths, such that filtered infrared radiation emerges from the Fabry-Perot interferometer, wherein the filtered infrared radiation at each tuning includes primarily light in a narrow wavelength band;
• directing the filtered infrared radiation to a detector, the detector producing an output indicating the intensity of the infrared radiation received at the detector;
• receiving the detector output;
• recording a first absorbance spectrum indicating the absorbance of the sample as a function of infrared radiation wavelength;
• replacing the first band pass filter with a second band pass filter, wherein the second band pass filter passes a different set of infrared radiation wavelengths than are passed by the first band pass filter;
• recording a second absorbance spectrum indicating the absorbance of the sample as a function of infrared radiation wavelength with the second band pass filter in place;
• and
• combining the first and second absorbance spectra into a composite absorbance spectrum.