According to Japanese Industrial Standard (JIS), the litmus paper has been changing color clearly from blue to red at pH 5, and from red to blue at pH 8, using buffer solution. But, when using general solution of acid or base, the color change of litmus paper does not happen at such pH. Therefore, when color of the litmus paper (made in TOYO-Roshi) changed practically by use of typical acid and base, the authors tried to measure and ascertain the pH value. The measured color changing pH value was 3. 9 in the case of using hydrochloric acid (HCl), and 11. 4, 4. 4, and 10._4 were respectively in the case of sodium hydroxide solution (NaOH), acetic acid (CH3COOH)and ammonia water (NH4OH). The absorption spectra of litmus solution, impure azolitmin solution and pure azolitmin solution, these many spectra were measured at various pH values. For example, the absorption spectra of impure azolitmin solution that effused by 30% ethyl alcohol on potato starch column are shown in figure 2. As shown in figure 3, when the difference of absorbance happens over 0. 020 on the same wavelength, the difference of the solution color can be confirmed by careful observation. As shown in figure 4, when the wavelength of the peak of absorption spectrum differs over 20nm on the same absorbance, the change of the solution color can be confirmed clearly. According to the figure 5, when the absor bance differs over 0. 020 and the wavelength differs over 20nm at the same time, a little difference of the color and a slight change of the color can be confirmed clearly. Therefore, by investigating many absorption spectra, the correlation between pH change and a little difference of wavelength can be obtained as coordinates. When the::e coordinates are plotted with pH value as ordinate and the wavelength as abscissa, the color change curve for pH is obtained. In figure 7, the two lines are color change curve for pH that based on the absorption spectra of the litmus solution on the market. And the line a and b point out that there are two kind of litmus. Line a represents one kind of litmus that the solution of itis not respond so sensitively, with the pH changes on acid side. But when the pH changes from 8 to 9 on basic side, the color of it changes from red to purple and blue. Line b represents another kind of litmus that the solution of it changes from red to purple and blue, with the pH changes from 3 to 4. In figure 8, line a is a color change curve for pH by impure azolitmin that effused by water on potato starch column, but when using of 30% ethyl alcohol, the curve of impure azolitmin effused by the column is shown line b or c. Line d shows a curve by Merk's azolitmin. Line e shows a curve by almost pure azolitmin that is purified by repeating -0f liquid chromatographic techniqne.
"},{"@language":"ja","@value":"リトマス試験紙とリトマス液の変色域は，参考図書等では混同して示されているように見うけられる。JIS規格ではリトマス試験紙はpH5.0 (or 8. 0)の緩衝溶液を一滴滴下したとき，鮮明な紅色 (or青色）を示すことが定められているが，これは試験紙の発色に関する規定であって，変色範囲をpH5.0-8.0と定めたものではない。リトマス液の発色についても同様で，JIS規格は本来試薬の純度が特級かー級かという品質保証のための規定であるのに，実際のリトマス液の変色域を示しているように受けとられ，しかもそれがリトマス試験紙の変色域と同じ値を示すものと思いこまれてきたのではなかろうか。東洋ろ紙製のリトマス試験紙を用いた測定ではかなり違った値になり，緩衝溶液による変色域は弱酸（酢酸）ー弱塩基（アンモニア水）のそれとほぼ同じで，pH4.4 -10.4となり，強酸（塩酸）一強塩基（水酸化ナトリウム水溶液）を用いたときの変色域はpH3.9 -11.4とずっと広くなる。つぎに簡易精製法による粗製リトマス溶液について吸収曲線を測定し， pH一色相変化曲線をつくって検討した。これによると，リトマスは酸性側のpH変化に対して鋭敏に変色するものと，比較的変色をしないものの二つの系統のものが市販されていることがわかった。これから，常温における炭酸のpHでは，リトマス液で赤くなるものとあまり変色しないものの二通りの結果が得られることの説明ができる。また簡易精製法に用いる溶媒は，水より30％ニチルアルコールを用いた方がやや鋭敏な粗製リトマス液が得られる。そしてリトマス色素が精製され，アゾリトミン主成分の液になるほどその変色が鋭敏になり，しかも酸性側のpH3-4とアルカリ性側のpH9-10-11の二か所の変色域を示すようになる。これは前に報告したことの裏づけともなっている。
"}],"abstractLicenseFlag":"disallow"}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1410019158920003201","@type":"Researcher","foaf:name":[{"@language":"en","@value":"ROKKAKU Miyako"},{"@language":"ja","@value":"六角 都"}],"jpcoar:affiliationName":[{"@language":"ja","@value":"千葉県富岡小学校"},{"@language":"en","@value":"Tomioka Elementary School, Chiba Prefecture"}]},{"@id":"https://cir.nii.ac.jp/crid/1410019158920003202","@type":"Researcher","foaf:name":[{"@language":"en","@value":"NAKAMURA Masato"},{"@language":"ja","@value":"中村 正人"}],"jpcoar:affiliationName":[{"@language":"ja","@value":"福井県高浜中学校"},{"@language":"en","@value":"Takahama Lower Secondary School, Fukui Prefecture"}]},{"@id":"https://cir.nii.ac.jp/crid/1410019158920003200","@type":"Researcher","foaf:name":[{"@language":"en","@value":"NAGASAWA Chitatsu"},{"@language":"ja","@value":"長沢 千達"}],"jpcoar:affiliationName":[{"@language":"ja","@value":"福島大学教育学部"},{"@language":"en","@value":"Faculty of Education, Fukushima University"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"03899039"},{"@type":"EISSN","@value":"24330140"}],"prism:publicationName":[{"@language":"en","@value":"Bulletin of Society of Japan Science Teaching"},{"@language":"ja","@value":"日本理科教育学会研究紀要"}],"dc:publisher":[{"@language":"en","@value":"Society of Japan Science Teaching"},{"@language":"ja","@value":"一般社団法人 日本理科教育学会"}],"prism:publicationDate":"1980","prism:volume":"21","prism:number":"1","prism:startingPage":"1","prism:endingPage":"8"},"reviewed":"false","url":[{"@id":"https://www.jstage.jst.go.jp/article/formersjst/21/1/21_1/_pdf"}],"availableAt":"1980","dataSourceIdentifier":[{"@type":"JALC","@value":"oai:japanlinkcenter.org:2013234804"},{"@type":"CROSSREF","@value":"10.11639/formersjst.21.1_1"},{"@type":"OPENAIRE","@value":"doi_________::9398003998ad90f590cf354eeae10628"}]}