Getting rid of Rayleigh Åsmund Rinnan

Introduction Fluorescence Light source Sample Detector Excites sample Emitted from sample

Introduction Fluorescence

Introduction PARAFAC X is the EEM a are the scores b are the emissionspectra c are the excitationspectra E is the residuals Can be seen as an expansion of PCA from two-way data to multi-way data

= A B C Introduction PARAFAC & Fluorescence

Catechol Hydroquinone

Introduction ”Faking” fluorescence

Introduction Light scatter

Introduction Light scatter – The trouble maker Excitation Emission 2nd order Rayleigh 1st order Rayleigh Raman

Introduction Light scatter

Introduction Bi-linearity

Introduction Why is this a problem? X X

Example Fluorescence & PARAFAC

Getting rid of Rayleigh Subtraction of standard Cut off and insert missing/ zeros Weights Modeling of Rayleigh

Subtracting a standard

Missing values Missing values Zeros Signal/ Data area Thygesen, Rinnan, Barsberg & Møller

Example 18 wood samples 4 different levels of p-benzoquinone adsorbed in the fiber cell walls 30 emission wavelengths x 35 excitation wavelengths Thygesen, Rinnan, Barsberg & Møller

WOW! None Weighted Non-Negativity Zeros

So, now Rayleigh is finished, right? The data presented so far is a bit simple  Sugar data Excitation Emission 1st order Rayleigh

Weighting - MILES Emission loadingsExcitation loadings

Band of missing values

Using a band of missing values Hard weights Emission loadingsExcitation loadings

Using a band of missing values MILES weights Emission loadingsExcitation loadings

Another method? Why, why, why? The Rayleigh scatter width has to be estimated quite accurately The band width of missing data should also be correct What about an automatic method of removing the Rayleigh scatter, that was not so prone to the estimation of the width of the Rayleigh scatter? Modeling the Rayleigh is the answer!

Modeling Rayleigh A Gauss-Lorentz curve fitting method

Modeling Rayleigh Rinnan, Booksh & Bro

Modeling Rayleigh

With constraints even better Emission loadingsExcitation loadings Rinnan, Booksh & Bro

Thanks to: Rasmus Bro, Karl Booksh, Lisbeth G Thygesen, Søren Barsberg, Jens K S Møller and Charlotte Andersen Thank you for your attention