Determination of pK_a's for thymol blue in aqueous medium: evidence of dimer formation.

详细信息    查看全文

• 作者：Balderas-Hern&aacute ; ndez ; Patricia ; Ramí ; rez ; M.Teresa ; Rojas-Hern&aacute ; ndez ; Alberto ; et. al.
• 关键词：Aqueous medium ; Formation constants ; Recrystallized thymol blue
• 刊名：Talanta
• 出版年：1998
• 出版时间：August, 1998
• 年：1998
• 卷：46
• 期：6
• 页码：1439-1452
• 全文大小：307 K

文摘

Formation constants for recrystallized thymol blue were determined in water, using the SQUAD and SUPERQUAD programs. The best model correlating spectrophotometric, potentiometric and conductimetric data was fitted with the dissociation of HL⁻=L²⁻+H⁺−log K=8.918±0.070 and H₃L₂⁻=2L²⁻+3H⁺−log K=29.806±0.133 with the SUPERQUAD program at variable low ionic strength (1.5×10⁻⁴–3.0×10⁻⁴ M); and HL=L²⁻+H⁺−log K=8.9±0.000, H₃L₂⁻ =2L²⁻+3H⁺−log K=30.730±0.032, H₄L₂=2L²⁻+4H⁺−log K=32.106±0.033 with SQUAD at 1.1 M ionic strength.