ABSTRACT

The cloud point (CP) of a mixture of Tween 80 (Tw 80) and neomycin sulphate (NS) was measured in an aqueous medium containing electrolyte (NaCl, NaNO₃, and Na₂SO₄). The CP of Tw 80 decreased when Tw 80 concentration increased. For various concentrations of Tw 80 (1.53 × 10^–2, 3.05 × 10^–2, and 6.11 × 10^–2 mol.kg^-1), CP values of the solution decreased with increasing additions of NS. CP values of NS+Tw 80 mixtures also decreased upon the addition of salts, following the trend: CP_Na2SO4 > CP_NaNO3 > CP_NaCl. Thermodynamic variables including standard-free energy (∆G⁰c), standard enthalpy (∆H⁰c), and standard entropy (∆S⁰c) of clouding as well as thermodynamic properties of transfer during phase transition were also determined. A linear relationship between enthalpy change (∆H⁰c) and entropy change (∆S⁰c) with an R² value of 0.9997–1.00 was obtained for the Tw 80+ NS mixture in aqueous electrolyte media.

摘要

在含有电解质（NaCl、NaNO ₃和Na ₂ SO ₄）的水性介质中测量吐温80（Tw 80）和硫酸新霉素（NS）的混合物的浊点（CP ）。当Tw 80 浓度增加时，Tw 80 的CP 降低。对于不同浓度的 Tw 80 （1.53 × 10 ^–2、3.05 × 10 ^–2和 6.11 × 10 ^–2  mol.kg ^-1），溶液的 CP 值随着 NS 添加量的增加而降低。NS+Tw 80 混合物的 CP 值也随着盐的加入而降低，趋势如下：CP _{Na 2 SO4} > CP _NaNO3 > CP _NaCl. 还确定了热力学变量，包括标准自由能 (Δ G ⁰ c)、标准焓 (Δ H ⁰ c) 和混浊的标准熵 (Δ S ⁰ c) 以及相变期间转移的热力学性质。对于水性电解质介质中的 Tw 80+ NS 混合物，获得了焓变 (Δ H ⁰ c) 和熵变 (Δ S ⁰ c)之间的线性关系，其中 R ²值为 0.9997–1.00。