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What method does the Trilogy use for Chlorophyll Acidification and Non-Acidification calculations?
When in direct concentration mode the following calculations will be used to calculate corrected chlorophyll and pheophytin a values for the acidification method and the corrected chlorophyll values for the non-acidification method.  
 
Acidification Method

I. Variables stored during calibration phase of fluorometer

Cstand[1]    = Concentration of standard 1
Fblank         = Fluorescence of Blank value
Fstand[1],B  = Fluorescence of standard 1 before acidification
Fstand[1],A  = Fluorescence of standard 1 after acidification
Fm              = Acidification Ratio = (Fstand[1],B – Fblank) / (Fstand[1],A – Fblank)

(Note: If using more than one standard for calibration take only pre-acidification readings
for standards 2-5)

II. Variables required from the sample analysis phase

Fsamp,B      = Fluorescence of sample before acidification
Fsamp,A      = Fluorescence of sample after acidification
Vsolvent      = Volume of solvent used to extract sample
Vwater        = Volume of water filtered


III. Interpolation equation used in end calculation of chlorophyll and pheophytin a concentrations

Interp,B         = Cstand[1] * (Fsamp,B - Fblank) / (Fstand[1],B - Fblank)
Interp,A         = Cstand[1] * (Fsamp,A - Fblank) / (Fstand[1],B - Fblank)


IV. End calculation for corrected chlorophyll and pheophytin a

Chlorophyll a concentration = [Fm/(Fm-1)] * (Interp,B - Interp,A) * (Vsolvent/ Vwater)
Pheophytin a concentration  = [Fm/(Fm-1)] * [(Fm * Interp,A) - Interp,B] * (Vsolvent/ Vwater)


V. End calculation for corrected chlorophyll a (Non-Acidification Method)

Chlorophyll a concentration = (Interp,B - Interp,A) * (Vsolvent/ Vwater)

(Note: Calibration values from the Acidification Method calibration curve can be used for calculating chlorophyll a concentrations from samples processed using Non-Acidification Method)