The goal of the emission scan is to detect light emitted will be at a longer wavelength than the excitation photons. If the emission scan were to start at 480 nm, the spectrum might be dominated by scattered 490 nm excitation photons, which are not the result of fluorescence events. If NO fluorescence occurs, the ONLY photons which will be detected are the original 490 nm excitation photons.
You mentioned that as you increase the voltage, you increase the intensity and the sensitivity. So, why you didn't use the highest voltage available? Is there a rule for what value you should use. Thank You
Increasing PMT voltage increases the noise apparent in the spectrum. Therefore, it is advantageous to use the lowest voltage that will result in several thousand counts. Also, the detector has an upper limit of about 65,000 counts, so increasing the PMT too much will result in readings that are off scale.
The goal of the emission scan is to detect light emitted will be at a longer wavelength than the excitation photons. If the emission scan were to start at 480 nm, the spectrum might be dominated by scattered 490 nm excitation photons, which are not the result of fluorescence events. If NO fluorescence occurs, the ONLY photons which will be detected are the original 490 nm excitation photons.
I am literally the dumbest graduate student ever so thank you so much for this video now I know how to design my experiment
if the molecule excites at 490 nm, why did you start the scanning at 500 nm? I just did a lab on this and im still confused.
an excited molecule will emit at a longer wavelength usually minimum around 30+ nm more.
You mentioned that as you increase the voltage, you increase the intensity and the sensitivity. So, why you didn't use the highest voltage available? Is there a rule for what value you should use. Thank You
Increasing PMT voltage increases the noise apparent in the spectrum. Therefore, it is advantageous to use the lowest voltage that will result in several thousand counts. Also, the detector has an upper limit of about 65,000 counts, so increasing the PMT too much will result in readings that are off scale.
You don't know how hold a cuvette