Comparison between two different hemichromes of hemoglobins (HbA and HbS) induced by n-dodecyl trimethylammonium bromide: chemometric study.

The interaction of n-dodecyl trimethylammonium bromide (DTAB) with oxyhemoglobin A and oxyhemoglobin S is investigated using UV-visible absorption spectra and chemometric resolution techniques. Oxyhemoglobins (A and S) induced to partial oxidized form (ferrihemoglobin) by DTAB and finally transform to fully oxidized hemichrome. Hemichrome mole fractions of HbS are more than HbA because of more hydrophobic interaction of DTAB-HbS in second set of binding site relative to DTAB-HbA. The visible spectra between 500 and 650 nm are used for identifying the present components in solution because each species of hemoglobin has a specific spectrum in this region. The number of components and mole fraction of mentioned species were determined by employing chemometric resolution techniques. Subspace comparison was used for determination of the number of components in each concentration of hemoglobin and DTAB. After the determination of components, multivariate curve resolution-alternating least square (MCR-ALS) by initial estimates of spectral profiles and proper constraints, was used to resolve the data matrix into pure concentration and spectral profiles. The results show that both number and mole fraction of components which were formed during hemoglobin (HbA and HbS) oxidation by DTAB were initial hemoglobin concentrations independent. Furthermore, in average the mole fraction of hemichrome of HbS is 14.4% more than HbA. On the other hand, the mole fraction of HbA ferrihemoglobin is 15.6% higher than HbS averagely.