title: Automated multiple flow-injection analysis in clinical chemistry: determination of total protein with Biuret reagent.
abstract: We have examined the feasibility of the automated multiple flow-injection technique for application to clinical chemistry by adapting to this system the biuret method for the determination of total protein. Samples were discretely and rapidly introduced into a continuously flowing, nonsegmented reagent stream by means of an automatic sampler and high-pressure injection valve. Pumps operating at 1380-2070 kPa (200-300 psi) were utilized to introduce the biuret reagent and saline diluent into the system separately at flow rates of 72 and 47 microL/s, respectively. Use of 20-microL sample and a 3.0-s reaction-delay coil was adequately sensitive for analysis for total protein by this method. Samples were analyzed at a rate of 150/h with no detectable between-sample carryover. Within-run precision studies yielded relative standard deviations of 2.5% and less. Total protein values obtained by this method correlated well with those obtained by centrifugal analyzer and bubble-segmented continuous-flow biuret methods.
mesh_terms: D001322:Autoanalysis / Q000379:methods; D001798:Blood Proteins / Q000032:analysis*; D003124:Colorimetry / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D012710:Serum Albumin, Bovine / Q000032:analysis
chemical_list: D001798:Blood Proteins; D007202:Indicators and Reagents; D012710:Serum Albumin, Bovine