Direct quantification of human serum albumin in human blood serum without separation of γ-globulin by the total internal reflected resonance light scattering of thorium-sodium dodecylbenzene sulfonate at water/tetrachloromethane interface

A direct quantification of human serum albumin (HSA) in blood serum samples without separation is proposed based on the measurements of total internal reflected resonance light scattering (TIR-RLS) at water/tetrachloromethane (H2O/CCl4) interfaces. In the pH range of 6.37-6.59, the coadsorption of the binary complex of HSA-Th(IV) with sodium dodecylbenzene sulfonate occurs at the H2O/CCl4 interface, forming an amphiphilic layer and displaying greatly enhanced TIR-RLS signals with the maximum peak located at 340-370 nm. The enhanced TIR-RLS intensity is in proportion to the HSA concentration in the range 0.15-1.0 mug ml(-1). The limit of detection is 14.4 ng ml(-1). The contents of HSA in blood serum samples were determined with the recovery of 97.1-102.3% and RSD of 0.6-2.9%, which are identical to those obtained according to the spectrofluorimetric method using chrome azurol S. (C) 2002 Elsevier Science (USA). All rights reserved.