in an autoanalyzer for analyzing a specimen such as urine and blood , protecting a measurement value of analysis from influence of a dispensing nozzle repeatedly used . for this purpose , a phosphonic acid derivative or a phosphoric acid derivative is chemically adsorbed on the surface of the dispensing nozzle . in this manner , a molecular layer for suppressing adsorption of biopolymers or adhesion of a specimen per se is formed on the nozzle surface to prevent accuracy of analysis from being influenced .