Validity of pseudo first order (PFO) approximation of binary adsorption kinetics

ADmix2isLin.m is a MATLAB function that gives the outcome 1 if modeling of binary adsorption kinetics by using the pseudo first order (PFO) approximation is appropriate, zero otherwise. Input parameters are parameters of reaction rate equation:
ka1 ka2 kd1 kd2 No1 No2 M
where
ka refers to rate constant of adsorption,
kd refers to rate constant of desorption
No refers to the overall number of adsorbate molecules in the system
M is the number of adsorption centers on the surface

Reaction rate equations are
N1'=ka1*No1*(M-N1-N2)-kd1*N1
N2'=ka2*No2*(M-N1-N2)-kd2*N2

The solutions to RRE are
N1=Ne1+Nt11*exp(-t/tau1)+Nt12*exp(-t/tau2)
N2=Ne2+Nt21*exp(-t/tau1)+Nt22*exp(-t/tau2)

Steady state values Ne1 and Ne2 are outcome of the function STEADY_mix2lin.m

Transient amplitudes Nt,ij are the outcome of the function TRANSmix2lin.m

Time constants are the outcome of the function TAUmix2lin.m