Abstract: An instrument for quantitative analysis includes two shutters, one of which prevents light from being introduced into a black box housing a cell holder from the outside through a port in which a cell may be placed in and taken out the black box, and the other of which prevents light from impinging on a photomultiplier tube which is in communication with the black box. The shutters are controlled by a control unit so that one of the shutters opens when the other closes. The instrument also includes detectors which detect whether or not the cell holder and the cell are disposed at predetermined positions, respectively. The detectors output signals to the control unit. The control unit controls an automatic pipetting device to restrict a sample from being introduced into the cell when both the cell holder and the cell are not disposed at the predetermined position.

Abstract: A process for determining the concentration of a component, such as glucose, uric acid or polyamine, in a body fluid, such as urine, blood, blood serum, blood plasma, saliva or gastric juice, includes processing the body fluid with a catalase or an immobilized catalase for decomposing hydrogen peroxide included in the body fluid. When the body fluid is processed with the calalase, an inhibitor which inhibits the reaction between the catalase and the component is added to the body fluid after processing with the catalase. The process also includes processing the body fluid with a strongly basic anion exchange resin. When the concentration of polyamine in the body fluid is measured, the body fluid is processed with an acylpolyamineamido hydrolysis enzyme for converting acetylpolyamine into polyamine in the body fluid. After processing the body fluid by the these operations, hydrogen peroxide produced by the reaction between an oxidase and the component is measured.