| 摘要 |
PURPOSE:To achieve a higher sensitivity and reproducibility, by providing a porous thin film on the surface of a transparent support to be impregnated with urease and an indicator. CONSTITUTION:A porous thin film such as unwoven fabric and filter paper is fastened on a transparent support comprising a polymer such as polycarbonate and polyvinyl compound by bonding and is impregnated with an urease solution and an indicator such as bromophenol blue and cresol red. The amount of the urease, the indicator and the assistant used is preferably 2-20wt%, 3-10wt% and 1-20wt% for solid concentration, for example, per the weight of a water soluble binder. The amount of heavy metal ion trapping shall be set within the range of about 0.5-20wt%. Thus, the amount of urea can be measured accurately.
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