Self referencing LED detection system for spectroscopy applications

A method for spectroscopically analyzing a sample in a cell comprising:

• (a) energizing a plurality of LEDs wherein each LED emits radiation at a selected wavelength;
• (b) transmitting the radiation to the cell and optically coupling the radiation to the sample;
• (c) transmitting the radiation from the sample via a fiber optic element to a sample photodetector;
• (d) transmitting the radiation from each LED via a fiber optic element to a reference photodetector;
• and
• (e) comparing the radiation simultaneously detected by said sample photodetector and said reference photodetector.

A method for spectroscopically analyzing samples comprising:

• (a) placing a plurality of samples in a plurality of cells;
• (b) energizing a plurality of LEDs to emit radiation at a plurality of selected wavelengths;
• (c) transmitting radiation at each selected wavelength via a fiber optic element to each said cell and coupling said radiation to each said sample;
• (d) transmitting radiation from each said cell sample via a fiber optic element to corresponding photodetector;
• (e) transmitting radiation at each selected wavelength to a reference photodetector;
• and
• (f) comparing radiation detected at each sample photodetector with the radiation detected at said reference photodetector.

An instrument for spectroscopically analyzing a sample comprising:

• a first LED which emits radiation at a first wavelength;
• a second LED which emits radiation at a second wavelength;
• a first transmitter channel comprising a fiber optic element to transmit radiation from the first LED to a first optical output port;
• a second transmitter channel comprising a fiber optic element to transmit radiation from the second LED to a second optical output port;
• a reference photodetector;
• a first reference channel comprising a fiber optic element to transmit radiation from the first LED to the reference photodetector;
• a second reference channel comprising a fiber optic element to transmit radiation from the second LED to the reference photodetector;
• a first sample photodetector in optical communication with a first input optical port;
• a second sample photodetector in optical communication with a second input optical port;
• and
• a microcontroller in communication with said first LED and second LED and said reference, first sample and second sample photodetectors so that said LEDs are energized and first and second signals indicative of radiation detected by said first and second sample photodetectors and a reference signal indicative of radiation detected by said reference photodetector are generated.

An instrument for spectroscopically analyzing a sample comprising:

• a first LED which emits radiation at a first wavelength;
• a second LED which emits radiation at a second wavelength;
• an optical mixer;
• a first transmitter channel comprising a fiber optic element to transmit radiation from the first LED to said optical mixer;
• a second transmitter channel comprising a fiber optic element to transmit radiation from the second LED to said optical mixer;
• a reference photodetector;
• a reference channel comprising a fiber optic element to transmit radiation from said optical mixer to said reference photodetector;
• an output channel comprising a fiber optic element to transmit radiation from said optical mixer to an output port;
• a sample photodetector in optical communication with an input port;
• a second input optical port;
• and
• a microcontroller in communication with said first LED and second LED and said reference and sample photodetectors so that said LEDs are energized to emit a train of radiation pulses and a sample signal indicative of radiation detected by said sample photodetector and a reference signal indicative of radiation detected by said reference photodetector are generated.