Streaming potential is created when an electrolyte solution is forced to flow pass a charged surface. For an uncoated fused silica capillary, the streaming potential is measured between the inlet and outlet vials while applying a pressure across the capillary. The changes in streaming potential can be used to characterize the properties of the capillary inner surface. In this work, HCl, NaCl, and NaOH solutions ranging from 0.4 to 6 mM were used as the background electrolyte (BGE) at temperatures of 15 to 35 °C for the mesurements. The streaming potential decreases with the increase in BGE concentration, and the trend is amplified at higher temperatures. When buffer solutions in the pH range of 1.5 to 12.7 were used as the BGE, streaming potential was shown to be sensitive to changes in pH but reaches a maximum at around 9.5. At pH < 3.3, no streaming potentials were observed. The pH of zero surface charge (streaming potential equals 0) changes with temperature, and is measured to be 3.3 to 3.1 when the temperature is changed from 15 to 35°C. Zeta potentials can be calculated from the measured streaming potential, conductivity, and the solution viscosity. Surface charge densities were calculated in this work using the zeta potentials obtained. We demonstrated that capillary surface conditions can significantly change the streaming potential, and with three different solutions, we showed that analyte-dependent adsorption can be monitored and mitigated to improve the peak symmetry and migration times reproducibility.

中文翻译：

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具有流动势的毛细管内表面条件的表征

当电解质溶液被迫流过带电表面时，就会产生流动电位。对于未涂层的熔融石英毛细管，在对毛细管施加压力的同时测量入口和出口样品瓶之间的流动电位。流动电位的变化可用于表征毛细管内表面的特性。在这项工作中，在 15 至 35 °C 的温度下，使用 0.4 至 6 mM 的 HCl、NaCl 和 NaOH 溶液作为背景电解质 (BGE) 进行测量。流动电位随着 BGE 浓度的增加而降低，并且在较高温度下这种趋势被放大。当 pH 值范围为 1.5 到 12.7 的缓冲溶液用作 BGE 时，流动电位对 pH 值的变化很敏感，但在 9.5 左右达到最大值。在 pH < 3.3 时，没有观察到流动电位。零表面电荷（流电势等于 0）的 pH 值随温度变化，当温度从 15°C 变化到 35°C 时测得的 pH 值为 3.3 到 3.1。Zeta 电位可以根据测量的流动电位、电导率和溶液粘度计算得出。在这项工作中使用获得的 zeta 电位计算表面电荷密度。我们证明了毛细管表面条件可以显着改变流动电位，并且通过三种不同的解决方案，我们表明可以监测和减轻分析物依赖性吸附，以提高峰对称性和迁移时间的重现性。1 当温度从 15°C 变为 35°C 时。Zeta 电位可以根据测量的流动电位、电导率和溶液粘度计算得出。在这项工作中使用获得的 zeta 电位计算表面电荷密度。我们证明了毛细管表面条件可以显着改变流动电位，并且通过三种不同的解决方案，我们表明可以监测和减轻分析物依赖性吸附，以提高峰对称性和迁移时间的重现性。1 当温度从 15°C 变为 35°C 时。Zeta 电位可以根据测量的流动电位、电导率和溶液粘度计算得出。在这项工作中使用获得的 zeta 电位计算表面电荷密度。我们证明了毛细管表面条件可以显着改变流动电位，并且通过三种不同的解决方案，我们表明可以监测和减轻分析物依赖性吸附，以提高峰对称性和迁移时间的重现性。