http://confocal-microscopy-list.275.s1.nabble.com/Rejected-posting-to-CONFOCALMICROSCOPY-LISTS-UMN-EDU-tp6866064p6870080.html
photon flux by calibrating against a known. Where would you get trustworthy
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> In order to measure quantum yields by the reference method, one only needs
> a defined measurement volume, a standard dye of known absorbance (at the
> microscope excitation wavelength) and quantum yield, and the absorbance of
> your sample at the microscope excitation wavelength. Quantum yield is then
> defined as QY=QYstandard*(A/Astandard) *(Fstandard/F)*(n^2/nstandard^2).
> Here n is the refractive index, F is the measured fluorescence intensity
> and A is the absorbance at the microscope excitation wavelength. Note that
> it is important that the standard and your unknown have similar emission
> spectra. Otherwise you will have to correct for the wavelength dependence
> of your microscope detection efficiency. Of course, if you have enough
> sample to measure absorbance, you can also measure fluorescence in a cuvette
> and then there is no point in going to the microscope.
>
> Jay
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:
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> Sent: Thursday, October 06, 2011 8:44 PM
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> Subject: Quantum yield
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> I got a rather left field enquiry today, as to whether there were
> calibration standards for quantum yield. It seems that the person wants to
> measure quantum yield under the microscope. My immediate response was that
> this is impossible. Quantum yield is easy enough to measure in a cuvette
> but would it be possible in a microscope? You could make a standard of a
> known concentration of fluorescein in a cell made by a
> spacer under the coverslip, but where do you go from there, if both
> quantum yield and extinction coefficient of the test sample are unknown?
>
> Any bright ideas?
>
> Guy
>
>
>
>
> Optical Imaging Techniques in Cell Biology
> by Guy Cox CRC Press / Taylor & Francis
>
http://www.guycox.com/optical.htm> ______________________________________________
> Associate Professor Guy Cox, MA, DPhil(Oxon) Australian Centre for
> Microscopy & Microanalysis, Madsen Building F09, University of Sydney, NSW
> 2006
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