Method and apparatus for automated determination of hemoglobin species

Apparatus for simultaneously determining the relative concentration of two solutions each of unknown concentration comprising:

• an optical system including a light source, means for splitting light from said light source into two paths, and first and second photodetectors each of said photodetectors providing an output proportional to the amount of light from said light source which is transmitted through one of said two solutions of unknown concentration;
• a source of reference voltage;
• dual channel conversion means each channel simultaneously receiving an input from said source of reference voltage and the output from a different one of said photodetectors;
• each of said dual channel conversion means for repeatedly simultaneously providing an output;
• and
• first arithmetic means repeatedly receiving an input from the output of each channel of said dual channel conversion means for repeatedly determining the relative concentration of said two solutions.

Apparatus for simultaneously determining the relative concentration of two solutions each of unknown concentration comprising:

• an optical system including a single light source, means for splitting light from said light source in two paths, and first and second photodetectors each of said photodetectors providing an output proportional to the amount of light from said light source which is transmitted through one of said two solutions of unknown concentration;
• a source of reference voltage;
• dual channel electrical conversion means, each channel simultaneously repeatedly receiving an output from a different one of said photodetectors, each of said channels including comparator means to compare the reference voltage to the output of the respective photodetector;
• an analog to digital converter for providing a digital value representative of the time during which the reference voltage exceeds the intensity of light received by said photodetector;
• first storage means for serially storing a first predetermined number of selected outputs from said analog to digital converter in the absence of a solution;
• and means for averaging a second predetermined number of values in said first storage means and providing an output, said second predetermined number being less than said first predetermined number, adder means for receiving second signals from said analog to digital converter in the presence of solutions and for receiving the output from said averaging means;
• and
• first arithmetic means for comparing the outputs from each of said channels for repeatedly determining the relative concentration of said two solutions.

A method for simultaneously determining the relative concentration of two solutions each of unknown concentration comprising the steps of:

• providing an optical system including a light source and first and second photodetectors;
• splitting the light from said light source into two paths;
• providing a source of reference voltage;
• comparing the reference voltage to the output of said first photodetector;
• simultaneously comparing the reference voltage to the output of said second photodetector;
• separately simultaneously and repeatedly deriving digital values representative of the time during which the reference voltage exceeds the intensity of light received by each photodetector said digital values being proportional to the actual concentration of each of said two solutions of unknown concentration;
• and
• comparing said derived digital values from one of said photodetectors with said derived digital values from the other of said photodetectors for providing an output indicative of the relative concentration of said two solutions.