Fig. 1. Flowchart of EMD-PLS modeling

Fig. 2. (a) 28 original temporal signals and (b) absorption spectra of 28 original amino acids samples

Fig. 3. EMD decomposed IMFs and residual function of concentration=0% sample

Fig. 4. The corresponding absorption spectra of concentration=0% sample for the first one IMFs (IMF1), two IMFs superposition (IMF1+IMF2), three IMFs superposition (IMF1+IMF2+IMF3), four IMFs superposition (IMF1+IMF2+IMF3+IMF4) and five IMFs superposition (IMF1+IMF2+IMF3+IMF4+IMF5)

Fig. 5. Scatter plots of the actual concentration versus the predicted concentration using (a) PLS model and (b) EMD-PLS model (IMF1+IMF2+IMF3+IMF4) for different concentrations of amino acids mixture samples