Matlab code to compute the corresponding absorption coefficients

 %% oxyhemoglobin and deoxyhemoglobin extinction.m
 % Author:Minh Anh Nguyen
 % minhanhnguyen@q.com
 % Matlab code to compute the corresponding absorption coefficients and plot 
 % the three absorption spectra on the same graph. 
 % Identify the low-absorption near-IR window that provide deep
 % penetration.
 % data for molar extinction coefficients of oxy-and deoxyhemoglobin and 
 % absorption coefficient of pure water as a function of wavelength are
 % copied directly from this website: http://omlc.org/spectra/hemoglobin/summary.html
 % Use physiologically representative values for both oxygen saturation SO2
 % and total concentration of hemoglobin CHb.
 % These values for the molar extinction coefficient e in [cm-1/(moles/liter)] were compiled by Scott Prahl using data from

    %W. B. Gratzer, Med. Res. Council Labs, Holly Hill, London
    %N. Kollias, Wellman Laboratories, Harvard Medical School, Boston 

%To convert this data to absorbance A, multiply by the molar concentration and the pathlength. For example, if x is the number of grams per liter and a 1 cm cuvette is being used, then the absorbance is given by

        %(e) [(1/cm)/(moles/liter)] (x) [g/liter] (1) [cm]
  %A =  ---------------------------------------------------
                     %     64,500 [g/mole]

%using 64,500 as the gram molecular weight of hemoglobin.

%To convert this data to absorption coefficient in (cm-1), multiply by the molar concentration and 2.303,

   % µa = (2.303) e (x g/liter)/(64,500 g Hb/mole) 
%where x is the number of grams per liter. A typical value of x for whole blood is x=150 g Hb/liter. 


close all; clear; clc;
load ('oxy_deoxy.mat');
figure;
semilogy(oxy_deoxy(:,1), oxy_deoxy(:,2),  'b', 'linewidth',1.5);
hold on
semilogy(oxy_deoxy(:,1), oxy_deoxy(:,3),  'r', 'linewidth',1.5);
title('The molar oxyhemoglobin and deoxyhemoglobin extinction','FontSize',14);
set(gca,'FontSize',14);
ylabel('molar extinction coefficient (cm^{-1}(moles/l)^{-1})','fontsize',14);
xlabel('wavelength (nm)','fontsize',14);
axis([250 1000 0 10^6]);
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 6 5]);
grid on;
legend('y = HbO2 ','y = Hb')

%% purewater

load ('purewater.mat');
figure;
semilogy(water(:,1), water(:,2),  'b', 'linewidth',1.5);
title('The pure water specific absorption coefficient ','FontSize',14);
set(gca,'FontSize',14);
ylabel(' specific absorption coefficient (um^{-1})','fontsize',14);
xlabel('wavelength (nm)','fontsize',14);
axis([300 1000 0 1*10^6]);
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 6 5]);
grid on;
legend('y = pure water')

%% all three graph
figure;
semilogy(oxy_deoxy(:,1), oxy_deoxy(:,3)*0.0054,  'r', 'linewidth',1.5);
hold on
semilogy(oxy_deoxy(:,1), oxy_deoxy(:,2),  'b', 'linewidth',1.5);
hold on
semilogy(water(:,1), water(:,2),  'y', 'linewidth',1.5);
title('The molar hemoglobin and water extinction','FontSize',14);
set(gca,'FontSize',14);
ylabel('molar extinction coefficient (cm^{-1}(moles/l)^{-1})','fontsize',14);
xlabel('wavelength (nm)','fontsize',14);
%axis([250 1000 0 0.6*10^6]);
axis([250 1000 0 1*10^6]);
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 6 5]);
grid on;
legend('y = HbO2 ','y = Hb', 'y = pure water')

%% Absorption
figure;
semilogy(oxy_deoxy(:,1), oxy_deoxy(:,2)*0.0054,  'b', 'linewidth',1.5);
hold on
semilogy(oxy_deoxy(:,1), oxy_deoxy(:,3)*0.0054,  'r', 'linewidth',1.5);
hold on
semilogy(water(:,1), water(:,2),  'y', 'linewidth',1.5);
title('The hemoglobin and water','FontSize',14);
set(gca,'FontSize',14);
ylabel('effective absorption coefficient (um^{-1})','fontsize',14);
xlabel('wavelength (nm)','fontsize',14);
axis([250 1000 0 1*10^6]);
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 6 5]);
grid on;
legend('y = HbO2 ','y = Hb', 'y = pure water')