In: Chemistry
Let's say for a chlorophyll solution we found the absorbance, and use d that with Beer's law to find the concentration. How come that concentration is different if we find the concentration of the same chlorophyll solution using the fluorescence?
According to Beer's law, we can express the absorbance of light by a sample solution can be specified as shown below.
A = 'cl, where ' = /2.303 ( = molar absorption coefficient and ' = molar extinction coefficient), c = concentration of the sample soluion and l = path length of sample
The intensity of fluorescence emission of weakly absorbing, dilute samples can be expressed as shown below.
F = I0(cl), where I0 = intensity of incident light and = quantum efficiency.
The above equation holds for dilute solutions only.
Hence, the concentration of the chlorophyll solution found by Beer's law can be much higher when compared to that found using the fluorescence.