Numerical analysis of absorption spectrum peak wavelength

The process of hemolysis of erythrocyte suspension induced by hydrochloric acid (HCl) is investigated by measuring the UV-Vis absorption spectrum in the range 250 nm - 750 nm at interval 1 nm. The spectrum is measured each 15 s which permitted to follow the changes in absorbance at different wavelengths during hemolysis. The kinetics of the hemolysis is monitored by the changes in the absorbance at 700 nm, and by the changes in the wavelength of the main absorbance peak in the spectrum due to the hemoglobin. Because of the finite number and discrete values of the wavelengths used in the measurement the real value of the peak wavelengths in the spectra must be found by additional processing of the experimental data. The procedure uses the first derivative of the spectrum (dA/dt) and a geometrical approach to calculate the value of the wavelength at which the first derivative dA/dt is equal to 0. The procedure smoothed the kinetic curve of the peak wavelength to a great extent. This permit to compare it to the curve of the absorbance at 700 nm and to make assumptions of the process that occurs during the acid hemolysis. The procedure could be applied to any process where there is a shift in the peaks’ wavelength.