阅读说明：本技术 一种聚碳酸酯类微塑料的解聚方法及其电化学检测方法 (Depolymerization method of polycarbonate micro plastic and electrochemical detection method thereof ) 是由 徐笠 梁刚 于 2021-06-18 设计创作，主要内容包括：本发明涉及塑料检测技术领域,尤其涉及一种聚碳酸酯类微塑料的解聚方法及其电化学检测方法。所述解聚方法包括：将聚碳酸酯类微塑料和解聚试剂混合,加热至回流,进行解聚反应,而后纯化得到双酚A溶液；其中,所述解聚试剂选自氢氧化钠、氢氧化钾、氨水、Na-2CO-3、柠檬酸钠、硫酸镁、硫酸钾、磷酸钠、氯化钾中的一种或几种。所述电化学检测方法包括：利用所述的解聚方法对聚碳酸酯类微塑料进行处理,再对得到的双酚A溶液进行电化学测定。本发明实现了聚碳酸酯类微塑料的解聚,同时实现了聚碳酸酯类微塑料间接电化学检测,建立了聚碳酸酯类微塑料间接定性、定量检测方法。(The invention relates to the technical field of plastic detection, in particular to a depolymerization method of polycarbonate micro-plastic and an electrochemical detection method thereof. The depolymerization method comprises the following steps: mixing polycarbonate micro plastic and a depolymerization reagent, heating to reflux, carrying out depolymerization reaction, and then purifying to obtain a bisphenol A solution; wherein the depolymerization agent is selected from sodium hydroxide, potassium hydroxide, ammonia water, Na 2 CO 3 One or more of sodium citrate, magnesium sulfate, potassium sulfate, sodium phosphate and potassium chloride. The electrochemical detection method comprises the following steps: the polycarbonate micro plastic is treated by the depolymerization method, and the obtained bisphenol A solution is subjected to electrochemical measurement. The inventionRealizes the depolymerization of the polycarbonate micro-plastic, simultaneously realizes the indirect electrochemical detection of the polycarbonate micro-plastic, and establishes an indirect qualitative and quantitative detection method of the polycarbonate micro-plastic.)

1. A method for depolymerizing a polycarbonate-based microplastic, comprising: mixing polycarbonate micro plastic and a depolymerization reagent, heating to reflux, carrying out depolymerization reaction, and then purifying to obtain a bisphenol A solution;

wherein the depolymerization agent is selected from sodium hydroxide, potassium hydroxide, ammonia water, Na₂CO₃One or more of sodium citrate, magnesium sulfate, potassium sulfate, sodium phosphate and potassium chloride.

2. The depolymerization method according to claim 1, wherein the depolymerization reaction is carried out in an organic alcohol solvent; the organic alcohol solvent is selected from one or more of methanol, ethanol, isopropanol, n-butanol, isoamylol and n-pentanol.

3. The depolymerization process according to claim 1 or 2, comprising the steps of:

(1) preparing the depolymerization reagent and the organic alcohol solvent into a depolymerization solution with a molar concentration of 0.001-2 mol/L;

(2) adding the polycarbonate micro plastic into the depolymerization solution, heating to reflux, and carrying out depolymerization reaction;

(3) after the depolymerization reaction is finished, purifying to obtain a bisphenol A solution; the purification specifically comprises the following steps: adding ultrapure water into a reaction system, uniformly mixing, centrifuging, and taking a water phase; and (3) adjusting the pH value of the water phase to 2-6, adding an organic solvent, uniformly mixing, and taking an organic phase.

4. The depolymerization method according to claim 3, wherein in the step (1), the molar concentration of the depolymerization solution is 0.5 to 1 mol/L.

5. The depolymerization method according to claim 3 or 4, wherein in the step (2), the time of the depolymerization reaction is 10 to 240 min.

6. The depolymerization method according to any one of claims 3 to 5, wherein in the step (3), the organic solvent is one or more selected from n-hexane, acetone, acetonitrile and chloroform.

7. An electrochemical detection method of polycarbonate micro plastic is characterized by comprising the following steps: treating polycarbonate-based microplastic by the depolymerization method according to any one of claims 1 to 6, and subjecting the obtained bisphenol A solution to electrochemical measurement.

8. The electrochemical detection method according to claim 7, comprising the steps of:

(1) preparing a bisphenol A standard substance and a potassium chloride solution into mixed standard liquids with different concentrations;

(2) respectively carrying out electrochemical measurement on the mixed standard solutions with different concentrations, and recording the oxidation current signal intensity to form a standard curve;

(3) and (3) dissolving the bisphenol A solution in a potassium chloride solution, performing electrochemical measurement under the same conditions as the step (2), and recording the oxidation current signal intensity.

9. The electrochemical detection method according to claim 8, wherein the concentration of the potassium chloride solution is 20 to 100 mM.

10. The electrochemical detection method according to claim 8 or 9, wherein the detection electrode for electrochemical measurement is a glassy carbon electrode, an ITO electrode, or a screen-printed carbon electrode;

preferably, the detection electrode is pre-treated in advance; the pretreatment specifically comprises the following steps: firstly, performing electro-activation treatment for 60-180 s by adopting a cyclic voltammetry, wherein the voltage setting range is-0.8V- + 1.4V; and then, treating for 3-5 times by adopting differential pulse voltammetry, wherein the voltage setting range is-0.4V- + 1.2V.

Technical Field

The invention relates to the technical field of plastic detection, in particular to a depolymerization method of polycarbonate micro-plastic and an electrochemical detection method thereof.

Background

The micro plastic is a plastic particle with the diameter less than 5 mm, and the micro plastic is a main carrier of hydrophobic pollutants in the environment due to small volume, large specific surface area (the specific surface area refers to the surface area of a porous solid substance per unit mass) and very strong pollutant adsorption capacity, is widely present in water, soil, atmosphere and other media, and has serious harm to the environment micro ecology.

Plastics are various according to the chemical synthesis monomers of the plastics, and the synthetic polycarbonate of bisphenol A (BPA) is an important type of plastics. In recent years, BPA-based synthetic polycarbonate materials have been used for the production of plastic (milk) bottles, drinking cups for infants, inner coatings for food and beverage (milk powder) cans, and the like, and have body images from mineral water bottles, medical instruments, and the inside of food packages. Research shows that BPA can cause endocrine dyscrasia, threaten the health of fetuses and children, and even induce diseases such as cancer, metabolic disturbance, induced precocious puberty and the like.

The micro plastic as a new pollutant is attracting more attention of researchers, but the current research focuses on the research of environmental behavior of the micro plastic, the action mechanism of the micro plastic and the environmental pollutants, the environmental toxicology of the micro plastic and the like, and the research of a micro plastic detection method is relatively less, so that the establishment of a rapid detection method of the micro plastic containing BPA has important significance for environmental risk assessment and occupational exposure risk assessment.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a depolymerization method of polycarbonate micro plastic, which can realize the high-efficiency degradation of the polycarbonate micro plastic; the invention also aims to provide an electrochemical detection method of the polycarbonate micro-plastic, which is beneficial to improving the detection accuracy, improving the reproducibility among detection batches and reducing the detection difficulty.

Specifically, the invention provides the following technical scheme:

the invention provides a depolymerization method of polycarbonate micro plastic, which comprises the following steps: mixing polycarbonate micro plastic and a depolymerization reagent, heating to reflux, carrying out depolymerization reaction, and then purifying to obtain a bisphenol A solution;

wherein the depolymerization agent is selected from sodium hydroxide, potassium hydroxide, ammonia water, Na₂CO₃Sodium citrate, magnesium sulfate, potassium sulfate and phosphorusOne or more of sodium and potassium chloride.

The invention discovers that the specific depolymerization reagent and the polycarbonate micro-plastic are adopted to carry out depolymerization reaction, so that the polycarbonate micro-plastic can be depolymerized to generate the bisphenol A, and the depolymerization efficiency is higher.

Preferably, the depolymerization reaction is carried out in an organic alcohol solvent; the organic alcohol solvent is selected from one or more of methanol, ethanol, isopropanol, n-butanol, isoamylol and n-pentanol.

In order to further improve the depolymerization efficiency, the depolymerization method is optimized, and the method comprises the following specific steps:

the depolymerization process comprises the steps of:

(1) preparing the depolymerization reagent and the organic alcohol solvent into a depolymerization solution with a molar concentration of 0.001-2 mol/L;

(2) adding the polycarbonate micro plastic into the depolymerization solution, heating to reflux, and carrying out depolymerization reaction;

(3) after the depolymerization reaction is finished, purifying to obtain a bisphenol A solution; the purification specifically comprises the following steps: adding ultrapure water into a reaction system, uniformly mixing, centrifuging, and taking a water phase; and (3) adjusting the pH value of the water phase to 2-6, adding an organic solvent, uniformly mixing, and taking an organic phase.

In the technical scheme, the organic phase is bisphenol A solution.

Preferably, in the step (1), the molar concentration of the depolymerization solution is 0.5 to 1 mol/L.

Preferably, in the step (2), the time for the depolymerization reaction is 10 to 240 min.

Preferably, in the step (3), the organic solvent is one or more selected from n-hexane, acetone, acetonitrile and chloroform.

Preferably, in step (3), hydrochloric acid, acetic acid, phosphoric acid, sulfuric acid, and the like are included as the pH adjusting agent.

Further, adjusting the pH value of the water phase to 2-4; further, the pH of the aqueous phase was adjusted to 3. The pH value of the water phase is adjusted to be acidic, which is beneficial to improving the accuracy of subsequent detection.

The invention also provides an electrochemical detection method of the polycarbonate micro plastic, which comprises the following steps: the polycarbonate-based microplastic is treated by the depolymerization method described above, and the obtained bisphenol A solution is subjected to electrochemical measurement.

Preferably, the electrochemical detection method comprises the following steps:

(1) preparing a bisphenol A standard substance and a potassium chloride solution into mixed standard liquids with different concentrations;

(2) respectively carrying out electrochemical measurement on the mixed standard solutions with different concentrations, and recording the oxidation current signal intensity to form a standard curve;

(3) and (3) dissolving the bisphenol A solution in a potassium chloride solution, performing electrochemical measurement under the same conditions as the step (2), and recording the oxidation current signal intensity.

The invention establishes a bisphenol A standard curve of a hydrolysate by an electrochemical technology; based on the determination of the depolymerization product BPA of the polycarbonate micro-plastic, the indirect electrochemical detection of the polycarbonate micro-plastic is realized, and the indirect qualitative and quantitative detection method of the polycarbonate micro-plastic is established.

According to the method, the mixed standard solutions with different concentrations are subjected to electrochemical measurement, and a standard curve is drawn according to the relation between the oxidation current signal intensity and the concentration of each mixed standard solution.

The specific reference of "mixed standard solutions with different concentrations" herein is known to those skilled in the art, and the present invention is not particularly limited thereto, and as many concentration gradients as possible may be set to improve the accuracy; for example, 10. mu.M, 20. mu.M, 50. mu.M, 100. mu.M, and 500. mu.M.

Preferably, the concentration of the potassium chloride solution is 20-100 mM.

Preferably, the detection electrode for electrochemical measurement is a glassy carbon electrode, an ITO electrode or a screen-printed carbon electrode;

further, the detection electrode is pretreated in advance; the pretreatment specifically comprises the following steps: firstly, performing electro-activation treatment for 60-180 s by adopting a cyclic voltammetry, wherein the voltage setting range is-0.8V- + 1.4V; and then, treating for 3-5 times by adopting differential pulse voltammetry, wherein the voltage setting range is-0.4V- + 1.2V.

The invention has the beneficial effects that:

(1) the depolymerization method of the polycarbonate micro-plastic provided by the invention has the advantages of cheap raw materials, no pollution, environmental protection and the like, can effectively improve the depolymerization efficiency, and realizes the high-efficiency degradation of the polycarbonate micro-plastic.

(2) The electrochemical detection method of the polycarbonate micro-plastic provided by the invention has the characteristics of simplicity, rapidness, sensitivity, strong anti-interference performance and the like, can realize qualitative and quantitative detection of bisphenol A, and has important significance for environmental risk assessment and occupational exposure risk analysis.

Drawings

FIG. 1 is a bisphenol A standard curve.

FIG. 2 is an electrochemical profile; wherein (A) is an electrochemical characteristic spectrum of a potassium chloride solution; (B) the electrochemical characteristic spectrum of a sample to be detected is obtained; (C) the electrochemical characteristic spectrum of the bisphenol A standard product is shown.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or instruments used are conventional products available from regular distributors, not indicated by the manufacturer.

Example 1

The embodiment provides a depolymerization method of polycarbonate micro plastic, which comprises the following steps:

(1) weighing 4g of potassium hydroxide, dissolving with isoamyl alcohol, and fixing the volume to 100ml to obtain a depolymerization solution;

(2) weighing 0.5g of polycarbonate micro plastic, placing the polycarbonate micro plastic in a round-bottom flask, adding 50ml of depolymerization solution, heating and refluxing for 3 hours, and carrying out depolymerization reaction;

(3) after the depolymerization reaction is finished, adding 20ml of ultrapure water into the reaction system, uniformly mixing, transferring the mixture into a centrifuge tube, transferring the water phase into the centrifuge tube after the centrifugation treatment, simultaneously adding a proper amount of hydrochloric acid into the centrifuge tube to adjust the pH value to 3.0, uniformly shaking, and standing for 5 min; adding 30ml of mixed solution of normal hexane and acetonitrile (normal hexane: acetonitrile: 2: 8) into the solution system after the acid adjustment, mixing and shaking, standing for 10min, and then transferring an organic phase in the solution system into a glass tube to obtain a bisphenol A solution.

Example 2

The embodiment provides an electrochemical detection method of polycarbonate micro-plastic, which comprises the following steps:

(1) preparing a bisphenol A standard substance and a potassium chloride solution into mixed standard solutions with the concentrations of 10 mu M, 20 mu M and 50 mu M respectively;

(2) performing electrochemical measurement on the mixed standard solutions with different concentrations, recording the oxidation current signal intensity, and drawing a standard curve according to the relation between the oxidation current signal intensity and the concentration of each mixed standard solution; the standard curve is shown in figure 1, the oxidation current signal intensity and the mixed standard solution have a good linear relation within the range of the experimental concentration of 10-50 mu M, and the linear relation is Y is 0.389X +4.057, and the result shows that the electrochemical method can be used for indirect and accurate quantitative detection of polycarbonate micro-plastics;

the detection electrode for electrochemical determination is an ITO electrode; pre-treating an ITO electrode in advance; the pretreatment specifically comprises the following steps: firstly, performing electro-activation treatment for 60-180 s by adopting a cyclic voltammetry, wherein the voltage setting range is-0.8V- + 1.4V; and then, treating for 3-5 times by adopting differential pulse voltammetry, wherein the voltage setting range is-0.4V- + 1.2V.

(3) And (3) dissolving the bisphenol A solution prepared in the example 1 in a potassium chloride solution to obtain a sample to be detected, performing electrochemical measurement under the same conditions as the step (2), recording the oxidation current signal intensity, and performing comparison judgment according to the electrochemical characteristic spectrum of the sample to be detected, wherein the judgment method is shown in Table 1.

TABLE 1 unknown sample to be tested determination method

The measurement results are shown in FIG. 2; wherein (A) is an electrochemical characteristic spectrum of a potassium chloride solution; (B) the electrochemical characteristic spectrum of a sample to be detected is obtained; (C) the electrochemical characteristic spectrum of the bisphenol A standard product is shown. As can be seen from fig. 2, the electrochemical characteristic spectrum (B) of the sample to be detected is completely consistent with the electrochemical characteristic spectrum (C) of the bisphenol a standard, and the background peak of the potassium chloride solution does not affect the detection of bisphenol a; the results show that the method can be used for qualitative analysis of polycarbonate micro-plastics.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.