阅读说明：本技术 一种钙离子选择性电极的感应膜及其制备方法 (Induction film of calcium ion selective electrodes and preparation method thereof ) 是由 罗艳 曹芮 刘海波 边宝丽 王红璐 戴俏俏 张玉珍 李丹 于 2019-09-05 设计创作，主要内容包括：本发明提供一种钙离子选择性电极的感应膜及其制备方法,所述感应膜以溶质和可挥发性溶剂混合均匀,可挥发性溶剂挥发后成膜,溶质中各组分质量比为：5％-15％的钙离子活性剂、0.5-3％的非离子表面活性剂、30％-50％聚合物材料、40％-60％增塑剂。本发明提供的一种钙离子选择性电极的感应膜及其制备方法,工序简单、使用实验室常用设备即可完成,使用材料成本低廉、对环境友好；制得的感应膜平整度高、均匀性好、韧性较好；用本发明的感应膜制备的钙离子选择性电极选择性好、测量精度高、稳定性好。(The invention provides an induction membrane of calcium ion selective electrodes and a preparation method thereof, wherein the induction membrane is formed by uniformly mixing a solute and a volatile solvent after the volatile solvent volatilizes, and the mass ratio of the components in the solute is 5-15% of a calcium ion active agent, 0.5-3% of a non-ionic surfactant, 30-50% of a polymer material and 40-60% of a plasticizer.)

The induction membrane of calcium ion selective electrodes is characterized in that the induction membrane is formed by uniformly mixing a solute and a volatile solvent, wherein the volatile solvent is volatilized to form a membrane, and the mass ratio of the solute to the calcium ion active agent is 5-15%, the nonionic surfactant is 0.5-3%, the polymer material is 30-50%, and the plasticizer is 40-60%.

2. The sensing membrane of calcium ion-selective electrodes according to claim 1, wherein the calcium ion active agent is basic calcium phosphate.

3. The sensing membrane of calcium ion-selective electrodes, according to claim 1, wherein the non-ionic surfactant is Triton X-100.

4. The sensing membrane of calcium ion-selective electrodes according to claim 1, wherein the polymer material is cellulose acetate.

5. The sensing membrane of calcium ion-selective electrodes according to claim 1, wherein the plasticizer is at least of tributyl phosphate, dimethyl phthalate and diethyl phthalate.

6. The sensing membrane of calcium ion-selective electrodes according to claim 1, wherein the volatile solvent is at least of acetone and methyl acetate.

7. The method for preparing a sensing membrane of calcium ion selective electrodes according to claims 1-6, wherein the method comprises the following steps:

5 to 15 percent of calcium ion active agent, 0.5 to 3 percent of nonionic surfactant, 30 to 50 percent of polymer material and 40 to 60 percent of plasticizer are used as solute and are mixed and stirred uniformly with a volatile solvent, the ratio of the solute to the solvent is 25 to 100mg/mL, the mixture is stirred hermetically at normal temperature for more than 4 hours, and the uniformly stirred mixture is stood and volatilized to form a film at normal temperature.

Technical Field

The invention belongs to the technical field of sensors and ion detection, and particularly relates to an induction membrane of calcium ion selective electrodes and a preparation method thereof.

Background

The calcium ion selective electrode can measure the concentration of calcium ions in a solution, and the principle is that the calcium ion selective sensing membrane responds to the calcium ions, when the membrane is contacted with the solution, movable ions in a membrane phase selectively interact with the calcium ions in the solution, the mandatory and selective effects cause uneven charge distribution of two phase interfaces, double electric layers are generated, potential difference is formed, the potential is called interface potential, the solution concentration is different, the interface potential strength is different, the relationship between the potential and the concentration follows the Nernst equation, namely the potential is in direct proportion to the negative logarithm of the concentration, the calcium ions are divalent ions, and the theoretical slope is 29.58 mV/pCa.

The calcium ion selective induction membrane is used as the core part of the calcium ion selective electrode and plays a decisive role in various performances of the electrode. In the prior art, PVC is mostly adopted as a polymer matrix, and the problems of change of the detection lower limit of an induction membrane and short service life caused by plasticizer leakage can occur; in addition, ETH1001, ETH129 and the like which are often used as calcium ion neutral carriers are basically imported medicines, and the purchase period is long and the price is high.

Therefore, it is necessary to provide new sensing membranes of ion selective electrodes and methods for preparing the same to solve the above problems.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide induction films for calcium ion selective electrodes and a preparation method thereof, and the induction films are low in cost, high in measurement accuracy and good in stability.

The technical scheme includes that the induction membrane of calcium ion selective electrodes is formed by uniformly mixing a solute and a volatile solvent, and forming a membrane after the volatile solvent is volatilized, wherein the mass ratio of the components in the solute is 5% -15% of a calcium ion active agent, 0.5% -3% of a nonionic surfactant, 30% -50% of a polymer material and 40% -60% of a plasticizer.

, the calcium ion activator is basic calcium phosphate.

, the non-ionic surfactant is triton X-100.

Further to step , the polymer material is cellulose acetate.

Further , the plasticizer is at least of tributyl phosphate (TBP), dimethyl phthalate (DMP) and diethyl phthalate (DEP).

Further , the volatile solvent is at least of acetone and methyl acetate.

In order to achieve the above purposes, the invention adopts the technical scheme that the preparation method of the induction membrane of the calcium ion selective electrodes comprises the following steps:

5 to 15 percent of calcium ion active agent, 0.5 to 3 percent of nonionic surfactant, 30 to 50 percent of polymer material and 40 to 60 percent of plasticizer are used as solute and are mixed and stirred uniformly with a volatile solvent, the ratio of the solute to the solvent is 25 to 100mg/mL, the mixture is stirred hermetically at normal temperature for more than 4 hours, and the uniformly stirred mixture is stood and volatilized to form a film at normal temperature.

The preparation method of the calcium ion selective induction membrane has the advantages that the preparation method is simple in process, can be completed by using common laboratory equipment, is low in cost of used materials, and is environment-friendly; the prepared induction film has high flatness, good uniformity and good toughness; the calcium ion selective electrode prepared by the induction membrane has good selectivity, high measurement precision and good stability.

Drawings

FIG. 1 shows that the calcium ion concentration is 10^-5～10^-2mol·L^-1Slope plots for examples 1-4, within the range;

FIG. 2 shows that the calcium ion concentration is 10^-3mol·L^-1Stability profiles in examples 1-4.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the following detailed description is given in steps with reference to the accompanying drawings, where it is obvious that the described embodiments are only some embodiments, but not all embodiments, of the present invention .

The invention provides an induction membrane of calcium ion selective electrodes, which is formed by uniformly mixing a solute and a volatile solvent, wherein the mass ratio of the solute to the volatile solvent is 5-15% of calcium ion active agent, 0.5-3% of nonionic surfactant, 30-50% of polymer material and 40-60% of plasticizer.

The calcium ion active agent is basic calcium phosphate. Basic calcium phosphate (Ca)₅(PO₄)₃(OH)) has excellent biocompatibility and bioactivity, and calcium ions in the calcium ion can be replaced by cations through ion exchange, so that the calcium ion selective electrode can be used as an ion active agent of the calcium ion selective electrode. The basic calcium phosphate is easy to synthesize and purify, easy to purchase and low in price.

The nonionic surfactant is triton X-100.

The polymer material is Cellulose Acetate (CA) is environment-friendly materials, is cellulose derived from plant bodies, has good transparency and mechanical properties, is cellulose derivatives which are most widely applied in fields at present, selects a proper plasticizer and can be used as a matrix material of the ion selective electrode.

The plasticizer is at least of tributyl phosphate (TBP), dimethyl phthalate (DMP) and diethyl phthalate (DEP).

The volatile solvent is at least of acetone and methyl acetate.

The invention also provides a preparation method of the induction membrane of calcium ion selective electrodes, which comprises the following steps of mixing and stirring uniformly 5-15% of calcium ion active agent, 0.5-3% of nonionic surfactant, 30-50% of polymer material and 40-60% of plasticizer as solute with volatile solvent, wherein the ratio of the solute to the solvent is 25-100mg/mL, sealing, mixing and stirring for more than 4 hours at normal temperature, and volatilizing and standing the uniformly stirred mixed solution at normal temperature to form a membrane.

With reference to table 1, the following description will be given in terms of 4 specific examples:

in examples 1-4, the solute is weighed according to the above ratio and put into a beaker, the solvent in the above ratio is added into a fume hood, clean magnetons are added, the beaker is sealed by a sealing film, and the beaker is placed on a magnetic stirrer to be stirred for more than 4 hours, so that the solute and the solvent are fully and uniformly stirred; and (3) transferring the uniformly stirred mixed solution into a clean and flat film-making container, slowly volatilizing the solvent at room temperature, and completely volatilizing the solvent to obtain the calcium ion selective induction film.

The obtained sensing membrane is placed in a calcium ion selective electrode, and connected with a calcium ion tester together with a reference electrode to test the slope and stability of the sensing membrane when the calcium ion concentration is 10^-5～10^-2mol·L^-1The slope in the range is shown in figure 1, at a calcium ion concentration of 10^-3mol·L^-1The stability in solution of (a) is shown in figure 2. The test result shows that the slope is close to the Nernst theoretical slope 29.58mV/pCa, and the stability is good in 30 days.

TABLE 1

Compared with the prior art, the preparation method of the calcium ion selective induction membrane provided by the invention has the advantages that the process is simple, the preparation can be completed by using common laboratory equipment, the cost of the used materials is low, and the preparation method is environment-friendly; the prepared induction film has high flatness, good uniformity and good toughness; the calcium ion selective electrode prepared by the induction membrane has good selectivity, high measurement precision and good stability.

It will be understood by those skilled in the art that the sensing film and the manufacturing method of the present invention are not limited to the examples described in the detailed description, and the above detailed description is only for the purpose of explaining the present invention and is not intended to limit the present invention. Other embodiments will be apparent to those skilled in the art from the following detailed description, which is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.