The color identification test paper null which possesses the revision paper

摘要

PURPOSE:To avoid false positivity and false negativity by adjusting the pH of a correcting paper piece corresponding to the item measured by a color identification test piece. CONSTITUTION:The pH of a correcting paper piece can be simply adjusted by pref. dipping the correcting paper piece in a colorless aqueous acid or alkali solution. As an acidic component, an org. acid such as tartaric acid, citric acid or oxalic acid and various buffer agents imparting an acidic condition can be used and, as alkali, a buffer agent imparting an alkaline condition such as sodium carbonate or sodium ethylenediaminetetraacetate can be used. The concn. of the aqueous solution to be used may be appropriately adjusted corresponding to the pH of the correcting paper piece.