In addition to caffeine spectra there are interfering
bands from other coffee components extracted by dichloromethane
and the peak of these bands was observed at
the wavelength of 308–310 nm. The compounds attributed
to this are known to be chlorogenic acid related
compounds (p-coumaroquinic acid). It is clear that this
interfering band has an effect on the maximum peak of
caffeine. Therefore, in this research matrices were eliminated
by Gaussian fit. The peak absorbance for calculating
the concentration of caffeine was obtained after
subtracting the Gaussian fit from the total caffeine
spectra.