双波长倍增差示法测定双嘧啶片中磺胺嘧啶和甲氧苄啶的含量

Thermodynamics of the Second Dissociation of Carbonic Acid in 10 Mass% Ethanol Water Mixture

本文论述了双波长倍增差示法同时测定双嘧啶片中磺胺嘧啶（ＳＤ）和甲氧苄啶（ＴＭＰ）的含量。本法是基于测定标准溶液ＳＤ（８～１４）×１０－６ｇ／ｍＬ，ＴＭＰ（１～２）×１０－６ｇ／ｍＬ和样品溶液在２４２．５ｎｍ和２２８．０ｎｍ处的吸收度。ＳＤ和ＴＭＰ的平均回收率与ＲＳＤ分别为１００．６０％，０．３３％和９８．２７％，１．５８（ｎ＝２０）。本法简便快捷，结果满意。

The determination of the second dissociation constant of carbonic acid in 10 mass% ethanol-water mixture has been made on cell of the type: Pt, H 2(101.325kPa) |, NaHCO 3(m 1), Na 2CO 3(m 2), NaCl(m 3), 10 mass% ethanol + water|AgCl-Ag at 278.15 to 318.15 K. The dependence of pK 2 at temperature: pK 2=23.38-1454.8/T-0.02643T. These results have been discussed in terms of the solute-solvent interactions and were compared with those in water and in 5 mass% urea-water mixture.