1. Assuming a stock concentration of 0.075 mM fluorescein, calculate the volume
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Question
1. Assuming a stock concentration of 0.075 mM fluorescein, calculate the volume necessary to make 100 mL of a 0.00009 mM fluorescein standard. The volumes will be fairly small and you'll use an eppendorf pipette to do the transfer. Report your answer in microliters.
2.
Consider the fluorescence spectra image below. Assuming a linear relationship is preserved between signal intensity and concentration, estimate in micromolar units the lower limit concentration that would result in a S/N ratio of 5.0. Estimate the noise level to be 0.01 intensity units. Report your answer with only 2 decimal places.
1. Assuming a stock concentration of 0.075 mM fluorescein, calculate the volume necessary to make 100 mL of a 0.00009 mM fluorescein standard. The volumes will be fairly small and you'll use an eppendorf pipette to do the transfer. Report your answer in microliters. Consider the fluorescence spectra image below. Assuming a linear relationship is preserved between signal intensity and concentration, estimate in micromolar units the lower limit concentration that would result in a S/N ratio of 5.0. Estimate the noise level to be 0.01 intensity units. Report your answer with only 2 decimal places.Explanation / Answer
For part 1, you can use the formula:
concentration(1)xV(1)=concentration(2)xV(2)
I recommend you convert everything to the standard units and in the end, you convert to microliters, so that,
0.075mM = 7.5x10^-8 M
0.00009mM = 9.0x10^-11 M
100mL = 0.1 L
Your calculations should look like this:
(7.5x10^-8 M)x V(1) = (9.0x10^-11 M)x(0.1 L)
V(1)= 1.2x10^-4 L = 0.12 mL = 120 microliters.
That was the correct answer. Hope it helps.
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