Multisource device for photometric analysis and associated chromogens

An optoelectronic instrument for measuring the absorbance of a plurality of samples, comprising:

• a plurality of LED-photodetector pairs, each of the said pairs being internally aligned so that light emitted by the said LED member is directed toward the photoreceptive surface of the corresponding said photodetector member of said pair, the said plurality of LED-photodetector pairs being arranged to form a spatial array of adjacent pairs,
• means for removably positioning said plurality of samples so that each said sample is positioned between the said LED member and the said corresponding photodetector member of a said pair, so that the light from the LED member of such pair passes through the said sample before striking the said photodetector member of said pair,
• electronic means for sequentially pulsing the LED members of said array, said sequential pulsing occurring in a sequence such that when absorbance of any particular said sample is being measured, the particular said LED member which corresponds to the said particular sample emits light, while said LED members which correspond to samples adjacent to said particular sample do not emit light simultaneously with said particular LED member, and
• electronic means for sequentially measuring the signal from each said photodetector during the interval in which its corresponding said LED member is emitting light, and calculating the absorbance or transmittance of corresponding said sample.