| 摘要 |
PURPOSE: To measure ionic strength and a pecific gravity with a high sensitivity by using a buffering agent added reagent containing at least one washing agent and one pH indicator and setting a pH change generated by adding the reagent to a degree lower than a color change. CONSTITUTION: A washing agent is pref. a quaternary ammonium type one or a zwitter-ion washing type one and pref. used in an impregnation soln. in a concn. of 0.04-5%. As an indicator, a substance known as a pH indicator having pH4-12 itself, especially, thymol blue or bromothymol blue is highly pref. The especially pref. concn. of the indicator after a sample is added is 1-50mmol/λ. As a buffering substance within a pref. pH range of 4-11, for example, a buffering agent containing phosphoric or boric acid ions is pref. and it is extremely pref. to use the same in a concn. of 0.10-0.18mol/l after the sample is added. The reagent of this compsn. directly depends on the specific gravity of a liquid to be measured in its color change showing ionic strength but does not depend on a pH change.
|
