JPH0733156Y2 - Electrophoresis cell for zeta potential measurement of flat plate sample - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an electrophoretic cell capable of measuring the zeta potential on a smooth plane of a target substance.

<Prior Art> In general, zeta potential is measured as an effective means for grasping the charge on the surface of a particle in a liquid and the property of a potential double layer, and the electrophoresis method is the simplest method for measuring zeta potential. Widely adopted. However, the substance to be measured by the electrophoresis method is limited to particles having a shape close to a sphere and having a uniform surface charge distribution. For example, when the zeta potential of a particle that has a plate-like morphology like mica or clay mineral and whose end surface is positively charged and its layer surface is negatively charged is measured by a conventional electrophoresis method, the obtained zeta potential is the end surface. And the layer surface, and also includes uncorrectable effects such as distortion of the electric double layer around the particle and particle shape. This is because conventional zeta potential measurement involves accommodating the target substance particles themselves together with a solution between transparent parallel plates or a capillary tube having a space inside, and measuring the migration speed by electrophoresing the particles themselves. This is because the method of calculating the zeta potential was adopted.

<Problems to be Solved by the Invention> An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide an electrophoretic cell capable of measuring the zeta potential of a specific smooth surface of a target substance.

<Means for Solving the Problems> In order to achieve the above object, the present invention employs the following means. That is, a translucent material is used as a material, and a concave portion having a uniform outer shape and a rectangular outer shape is provided in the central portion of one surface of a rectangular cell base whose both surfaces are parallel to each other. Is an independent electrode insertion hole from the upper end surface of the cell base, and the same transparent material is used as a material. It is an electrophoretic cell for zeta-electric measurement of a layer surface that is detachably configured so as to be inserted and covered in a watertight manner. Both surfaces of the cell base and the cell lid are subjected to optical polishing to the extent of a spectrophotometer cell, and watertight sealing of these is performed using grease, paraffin, or Teflon paste.

<Operation> The zeta potential is measured by the electrophoresis cell of the present invention by the following method. That is, a solution is put in a concave portion of a cell base which is usually made of a transparent material such as quartz glass, and a tracer such as colloidal particles made of an inorganic or organic substance is suspended in the liquid, and the concave portion is treated with mica The cell is closed with a cell lid made of a flat plate of a zeta potential measurement target substance such as quartz, and the zeta potential of the flat cell lid is obtained by measuring the electroosmotic flow velocity distribution in the closed cell. Specifically, after measuring the migration velocity of tracer particles at each level in the depth direction of the recess of the cell base and obtaining the electroosmotic flow velocity distribution of the solution in the cell as a function of the depth of the recess, the theory of Mori and Okamoto To determine the electroosmotic flow velocity on the wall surface of the flat plate sample. Then, the electroosmotic flow velocity on the wall surface of the flat plate sample is substituted into the Helmholtz-Muskowski equation to calculate the zeta potential.

<Embodiment> Hereinafter, the present invention will be described in detail with reference to the drawings of the embodiment.

The electrophoretic cell used in this example is made of quartz glass, and as shown in FIGS. 1 to 5, a concave portion 2 having a depth of 1 mm is provided at the center of a rectangular cell base 1, and the concave portion is formed. Electrode insertion holes 3 and 3 are provided on both left and right sides of the electrode, and as the electrode 4, a palladium electrode having a thickness of 0.7 mm as shown in FIG. 6 was used. The cell lid 5 is a flat plate as shown in FIGS. 7 and 8, and its material is two types, mica and quartz. In addition, 1 × 10 ⁻³ MKCl as a supporting electrolyte was made to coexist in water to be put in the concave portion 2, HCl and KOH were used as pH adjusters, and the experiment was conducted at 25 ° C.

As a specific experiment, as shown in FIG. 9, a microscope 11 is arranged behind the electrophoretic cell 10, a He-Ne laser beam is applied to the electrophoretic cell 10 from above, and a video camera 12, a video recorder 13 and a video recorder are used. Observed on monitor 14.

As a result, Fig. 10 shows the electricity in the cell at pH 3 when sealed with a mica plate and a quartz glass plate (mica-quartz system) and with the same two quartz glass plates (quartz-quartz system). The permeation flow rate is shown. As is clear from FIG. 10, the electroosmotic flow velocity distribution of the solution in the cell in the quartz-quartz system shows a symmetrical parabola, while the electroosmotic flow velocity distribution of the solution in the cell in the mica-quartz system shows an asymmetric parabola. . The electroosmotic flow velocity at the quartz glass / aqueous solution interface obtained from the electroosmotic flow velocity distributions of the mica-quartz system and the quartz-quartz system is
It almost agreed. This corresponds to that the zeta potentials of the quartz glass flat plate obtained from the respective measurements are substantially equal, and it is shown that the zeta potential of the flat plate sample can be measured regardless of the shape of the electroosmotic flow velocity distribution. Furthermore, the electroosmotic flow velocity at the mica plate (mica layer surface) / aqueous solution interface at pH 3 showed a positive value higher than that at the silica glass plate / aqueous solution interface. This means that the zeta potential of the mica layer surface is negatively larger than that of the quartz glass plate.

Next, in Fig. 11, the zeta potentials of the mica plate and the quartz glass plate measured by the electroosmosis method are shown as a function of pH. The zeta potentials of the quartz glass plate obtained when the both sides of the cell were sealed with a quartz glass plate (○) and when one side was sealed with a mica plate (●) are also apparent in Fig. 10 above. Almost matched.

<Effect of Device> As described above, according to the present invention, not the zeta potential of the entire particles of various substances but the zeta potential on a specific smooth surface of the target substance can be obtained. The effect is that the characteristics can be grasped more accurately.

[Brief description of drawings]

1 is a front view of the cell base of the present invention, FIG. 2 is a plan view of the same,
FIG. 3 is a side view of the same, FIG. 4 is an end view of line IV-IV in FIG.
FIG. 5 is an end view taken along the line VV of FIG. 1, FIG. 6 is an explanatory view of a main part of an electrode portion, FIG. 7 is a front view of a cell lid of the present invention, FIG. The figure is a schematic diagram of the zeta potential measuring device according to the present invention, FIG. 10 is a graph showing the relationship between liquid flow velocity distribution and depth, and FIG. 11 is a graph showing the relationship between pH and zeta potential.

Claims (1)

[Scope of utility model registration request] 1. A recess having a uniform depth and a rectangular outer shape is provided at the center of one surface of a rectangular cell base whose both sides are parallel to each other, and which is made of a light-transmissive material. Is an electrode insertion hole that is independent of the recess and is made from the upper end surface of the cell base. On the other hand, a transparent material is also used as a material. An electrophoretic cell for measuring zeta potential of a flat plate sample, characterized in that the flat plate material is inserted so as to be covered in a watertight manner so as to be detachable.