LIGHT SCATTERING-BASED DETERMINATION OF FIBRINOGEN IN HUMAN PLASMA USING AN AUTOMATED CONTINUOUS SYSTEM

A simple light scattering method for the determination of fibrinogen i n plasma is presented. The method is based on the analyte precipitatio n in the presence of ammonium sulphate in glycine hydrochloride buffer . The approach is developed by using a simple flow injection manifold where the light scattered by the solid suspension formed is monitored in a conventional spectrofluorimeter with an incident wavelength of 34 0nm. The optimized method provided a linear determination range betwee n 1.0x10(-3) and 2.0x10(-2) gl(-1) of fibrinogen with a precision, exp ressed as rsd%, of +/-1.33 and +/-1.30 for fibrinogen concentrations o f 5x10(-3) and 1.2x10(-2)gl(-1), respectively. The fast kinetics of th e precipitation reaction and simplicity of the method provided a high sampling frequency, estimated at 80 h(-1). The method was applied to t he determination of fibrinogen in 35 human plasma samples from healthy and sick individuals, after a 1 : 250 dilution with an acceptable cor relationship with a standard nephelometric method and recoveries betwe en 89% and 108%.