Final answer:
The Beer-Lambert Law is what describes the correlation between the absorbance of cyanmethemoglobin at 540 nm and hemoglobin concentration, allowing the determination of hemoglobin levels in a sample by measuring its absorbance.
Step-by-step explanation:
The law that describes the correlation between the absorbance of cyanmethemoglobin at 540 nm and hemoglobin concentration is Beer-Lambert Law. This law states that absorbance is directly proportional to the concentration of a chromophore in solution, provided that the sample follows Beer's law criteria. An important aspect to consider is that the absorbance also depends on the path length; commonly, it is set to 1 cm, which simplifies the calculations. Using the Beer-Lambert Law equation A = εcl, where A is the absorbance, ε (epsilon) is the molar absorptivity, c is the concentration, and l is the path length, one can determine the concentration of hemoglobin present in a sample. For instance, if the value of ε for cyanmethemoglobin is known, and you measure an absorbance at 540 nm, you can calculate the hemoglobin concentration in the sample.