Total internal reflected resonance light scattering determination of protein in human blood serum at water/tetrachloromethane interface with Arsenazo-TB and Cetyltrimethylammonium bromide

A direct quantification of protein in human blood serum samples is proposed based on the measurement of total internal reflected resonance light scattering (TIR-RLS) at water/tetrachloromethane (H₂O/CCl₄) interfaces. At pH 4.10 and in the presence of Cetyltrimethylammonium bromide (CTAB), the interaction of Arsenazo-TB (ATB) with human serum albumin (HSA) results in strong enhanced TIR-RLS signals with the maximum spectra peak located at 330 nm. The enhanced TIR-RLS intensity at 330 nm was found to be proportional to the concentration of HSA in the range 0.5-42.3 μg/ml and its limit of determination (3σ) is 198 ng/ml. The content of HSA in blood serum samples were determined with the recovery of 97-103% for standard addition experiment.