阅读说明：本技术 双波长共振瑞利散射法测定全氟辛烷磺酸的方法及应用 (Method for measuring perfluorooctane sulfonate by dual-wavelength resonance Rayleigh scattering method and application ) 是由 贺锦灿 宋嘉怡 邱佩佩 白研 毋福海 于 2019-11-05 设计创作，主要内容包括：本发明涉及双波长共振瑞利散射法测定全氟辛烷磺酸的方法,属于环境监测研究领域。全氟辛烷磺酸的共振瑞利散射信号很弱,本发明采用在一定的条件下,甲苯胺蓝与全氟辛烷磺酸形成一种离子缔合物,使共振瑞利散射信号显著增强,并在345nm和506nm处出现两个特征峰。在选定的条件下,全氟辛烷磺酸溶液浓度与共振瑞利散射强度存在良好的线性关系,据此建立了一种定量分析全氟辛烷磺酸的双波长共振瑞利散射方法。本发明适用于环境水样中全氟辛烷磺酸的检测,具有简单、快速、灵敏度高、抗干扰能力强等优点。(The invention relates to a method for measuring perfluorooctane sulfonate by a dual-wavelength resonance Rayleigh scattering method, belonging to the field of environmental monitoring research. The resonance Rayleigh scattering signal of the perfluorooctane sulfonate is very weak, under a certain condition, toluidine blue and the perfluorooctane sulfonate form an ionic association, so that the resonance Rayleigh scattering signal is obviously enhanced, and two characteristic peaks appear at 345nm and 506 nm. Under the selected condition, the concentration of the perfluorooctane sulfonate solution and the resonant Rayleigh scattering intensity have a good linear relation, and accordingly the dual-wavelength resonant Rayleigh scattering method for quantitatively analyzing the perfluorooctane sulfonate is established. The method is suitable for detecting the perfluorooctane sulfonate in the environmental water sample, and has the advantages of simplicity, rapidness, high sensitivity, strong anti-interference capability and the like.)

1. The method for measuring perfluorooctane sulfonate by using the dual-wavelength resonance Rayleigh scattering method is characterized by comprising the following steps: the method comprises the following steps:

pretreatment of S1 perfluorooctane sulfonate standard: sequentially adding a buffer solution, a toluidine blue dye solution and a series of perfluorooctane sulfonic acid standard solutions into a 10mL colorimetric tube, fixing the volume to 10mL by using triple distilled water, shaking up, standing at room temperature for 10min to obtain an ionic associate, and setting the ionic associate as an experimental group; simultaneously setting a blank group without adding the perfluorooctane sulfonate solution;

s2 plots Δ I and perfluorooctane sulfonic acid concentration standard curves: placing the ion association complex obtained in S1 in a quartz cuvette, placing in an F-2500 type fluorescence spectrophotometer, synchronously scanning with λ ex ═ λ em, and respectively recording Rayleigh scattering intensity I of the experimental group and blank group at 345nm₁And I₀₁And calculating Δ I₁＝I₁-I₀₁(ii) a The Rayleigh scattering intensity I at the wavelength of 506nm of the experimental group and the blank group is recorded simultaneously₂And I₀₂And calculating Δ I₂＝I₂-I₀₂Let Δ I be Δ I₁+ΔI₂(ii) a Drawing a standard curve of the delta I and the concentration C of the perfluorooctane sulfonate, and solving a linear regression equation;

preparation of S3 sample: respectively filtering a water sample to be detected by using quantitative filter paper and a 0.22um water system filter membrane, and filtering by using cation exchange resin to obtain a sample working solution;

determination of perfluorooctanesulfonic acid content in the S4 sample: measuring the working solution of S3 sample according to the detection method of S1, and measuring the difference Delta I of the resonant Rayleigh scattering intensity at the wavelength of 345nm and 506nm₁+ΔI₂And calculating Δ I ═ Δ I₁+ΔI₂Substituting the delta I into the linear regression equation of the step S1 to obtain the content of the perfluorooctane sulfonate in the sample working solution, and simultaneously performing a standard addition recovery experiment.

2. The method for measuring perfluorooctane sulfonate according to claim 1, wherein the buffer solution in step S1 is one of citric acid-sodium citrate buffer solution, acetic acid-sodium acetate buffer solution, phosphate buffer solution, and B-R buffer solution.

3. The method for measuring perfluorooctane sulfonic acid by the dual wavelength resonance rayleigh scattering method according to claim 2, wherein the buffer solution is a B-R buffer solution.

4. The method for measuring perfluorooctane sulfonate according to claim 3, wherein the pH of the B-R buffer solution is 4.0.

5. The method for measuring perfluorooctane sulfonate by the dual wavelength resonance rayleigh scattering method according to claim 1, wherein the concentration of the toluidine blue dye solution in the step S1 is 2.5 x 10^-5mol/L。

6. The method for measuring perfluorooctane sulfonic acid by the dual wavelength resonance rayleigh scattering method according to claim 1, wherein the concentrations of the serial perfluorooctane sulfonic acid solutions in the step S1 are respectively 0.02, 0.04, 0.08, 2, 4, 6, 8, 10 umol/L.

7. The method for measuring perfluorooctane sulfonate by the dual wavelength resonance rayleigh scattering method according to claim 1, wherein the volume of the buffer solution in step S1 is 1.5mL, the volume of the toluidine blue dye solution is 1.0mL, and the volume of the perfluorooctane sulfonate solution is 3.0 mL.

8. The method for measuring perfluorooctane sulfonic acid by the two-wavelength resonance rayleigh scattering method according to claim 1, wherein the scanning speed in step S1 is 3000nm/min and the slit width is 10.0 nm.

9. The method for measuring perfluorooctane sulfonate by the dual wavelength resonance rayleigh scattering method according to claim 1, wherein the volume of the ionic complex in step S2 is 3.0mL, and the volume of the sample working solution in step S4 is 3.0 mL.

10. The application of the method for determining perfluorooctane sulfonate by the dual-wavelength resonance Rayleigh scattering method according to any one of claims 1 to 9 in detecting perfluorooctane sulfonate in an environmental water sample.

Technical Field

The invention relates to a method for measuring perfluorooctane sulfonate by a dual-wavelength resonance Rayleigh scattering method, belonging to the field of environmental monitoring research.

Background

Perfluorinated compounds are a class of persistent organic pollutants and are easily accumulated in organisms. Perfluorooctanesulfonic acid (PFOS), one of the most widely used perfluorinated compounds, is chemically very stable and difficult to decompose. The perfluorooctane sulfonate can enter into the organism through a food chain to accumulate, and has potential toxic effects on the reproductive system, the nervous system, the immune system and the endocrine system of the organism. The pollution condition of the perfluorinated compounds is widely concerned by various countries at present. Perfluorooctanesulfonic acid, once taken into the body, is difficult to be excreted by the organism through metabolism, and as it accumulates in the organism, it causes adverse damage to the reproductive system, serum, respiratory system, liver, immune system, and has been listed in the list of class 2B carcinogens published by the international agency for research on cancer of the world health organization.

At present, the methods for analyzing and measuring perfluorooctane sulfonate mainly comprise a gas chromatography-mass spectrometry combined method, a high performance liquid chromatography-mass spectrometry combined method and the like. The common detection method has one or more problems of high price of required instruments, long analysis time, complex pretreatment process and the like, so that the establishment of a simple and rapid method for detecting perfluorooctane sulfonate is of great significance.

The instrument of the resonance Rayleigh scattering method is simple and convenient to operate, is rapid and sensitive, and has been applied to analysis and research in a plurality of fields such as biology, environment, materials and the like. The invention applies a resonance Rayleigh scattering method to the analysis of perfluorooctane sulfonate, and establishes a new resonance Rayleigh scattering method for measuring the perfluorooctane sulfonate by researching the reaction conditions and the analysis influence factors of the perfluorooctane sulfonate.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method for measuring perfluorooctane sulfonate by a toluidine blue probe dual-wavelength resonance Rayleigh scattering method. According to the method, under a certain condition, toluidine blue solution is combined with perfluorooctane sulfonic acid to form an ionic associate, so that a resonance Rayleigh scattering signal of a system is obviously enhanced, and two characteristic peaks appear at 345nm and 506 nm. Under the selected conditions, the perfluorooctane sulfonic acid has a good linear relation with the resonant Rayleigh scattering intensity in the range of 0.02-8.00umol/L, and accordingly, a resonant Rayleigh scattering method for measuring the perfluorooctane sulfonic acid is established.

In order to achieve the above object, the present invention provides a method for measuring perfluorooctanesulfonic acid by a toluidine blue probe two-wavelength resonance rayleigh scattering method, wherein perfluorooctanesulfonic acid is added to a toluidine blue solution under an acidic condition, both are electrostatically reacted to generate an ion associate, and the concentration of perfluorooctanesulfonic acid is indirectly measured by measuring the intensity of the resonance rayleigh scattering spectrum of the ion associate.

The method for measuring perfluorooctane sulfonate by using the dual-wavelength resonance Rayleigh scattering method comprises the following steps of:

pretreatment of S1 perfluorooctane sulfonate standard: sequentially adding a buffer solution, a toluidine blue dye solution and a series of perfluorooctane sulfonic acid standard solutions into a 10mL colorimetric tube, fixing the volume to 10mL by using triple distilled water, shaking up, standing at room temperature for 10min to obtain an ionic associate, and setting the ionic associate as an experimental group; simultaneously setting a blank group without adding the perfluorooctane sulfonate solution;

s2 plots Δ I and perfluorooctane sulfonic acid concentration standard curves: placing the ion association complex obtained in S1 in a quartz cuvette, placing in an F-2500 type fluorescence spectrophotometer, synchronously scanning with λ ex ═ λ em, and respectively recording Rayleigh scattering intensity I of the experimental group and blank group at 345nm₁And I₀₁And calculating Δ I₁＝I₁-I₀₁(ii) a The Rayleigh scattering intensity I at the wavelength of 506nm of the experimental group and the blank group is recorded simultaneously₂And I₀₂And calculating Δ I₂＝I₂-I₀₂Let Δ I be Δ I₁+ΔI₂(ii) a Drawing a standard curve of the delta I and the concentration C of the perfluorooctane sulfonate, and solving a linear regression equation;

preparation of S3 sample: respectively filtering a water sample to be detected by using quantitative filter paper and a 0.22um water system filter membrane, and filtering by using cation exchange resin to obtain a sample working solution;

determination of perfluorooctanesulfonic acid content in the S4 sample: measuring the working solution of S3 sample according to the detection method of S1, and measuring the difference Delta I of the resonant Rayleigh scattering intensity at the wavelength of 345nm and 506nm₁+ΔI₂And calculating Δ I ═ Δ I₁+ΔI₂Substituting the delta I into the linear regression equation of the step S1 to obtain the content of the perfluorooctane sulfonate in the sample working solution, and simultaneously performing a standard addition recovery experiment.

Preferably, the buffer solution is one of citric acid-sodium citrate buffer solution, acetic acid-sodium acetate buffer solution, phosphate buffer solution and B-R buffer solution.

Preferably, the buffer solution is a B-R buffer solution

Preferably, the pH of the B-R buffer solution is 4.0.

Preferably, the concentration of the toluidine blue dye solution in the step S1 is 2.50 × 10^-5mol/L。

Preferably, the concentration of the perfluorooctane sulfonate solution in the step S1 is 0.02, 0.04, 0.08, 2, 4, 6, 8, 10umol/L, respectively.

Preferably, in step S1, the volume of the buffer solution is 1.5mL, the volume of the toluidine blue dye solution is 1.0mL, and the volume of the perfluorooctane sulfonic acid solution is 3.0 mL.

Preferably, the scanning speed in step S1 is 3000nm/min, and the slit width is 10.0 nm.

Preferably, the volume of the ionic complex in the step S2 is 3.0mL, and the volume of the sample working solution in the step S4 is 3.0 mL.

Correspondingly, the invention also provides application of the method for determining the perfluorooctane sulfonate by the dual-wavelength resonance Rayleigh scattering method in detecting the perfluorooctane sulfonate in an environmental water sample.

The inventors of the present invention demonstrated that the acidity of the solution significantly affects the reaction system through examples 2 to 3, and when the pH of the B-R buffer solution is 4.0, toluidine blue is uniformly dispersed in the system, and the toluidine blue and perfluorooctane sulfonic acid aggregate together to form an ion association with a large volume, so that the resonance rayleigh scattering signal is the strongest. The inventor examines common anions, metal cations and EDTA pair 4 × 10^-6The selectivity of the method is evaluated according to the influence of the determination of mol/L perfluorooctane sulfonic acid, and the result shows that the RSD of the change of the delta I value is within +/-10 percent, which indicates that the method is used for determining the perfluorooctane sulfonateThe octane sulfonic acid has good selectivity and strong anti-interference capability in measurement.

The invention also determines the content of perfluorooctane sulfonate in river water and river water by the embodiment 4, and simultaneously carries out a standard recovery experiment, and the result shows that the standard curve obtained by the resonance Rayleigh scattering is that delta I is 1729.6c-265.90, R²0.9951, wherein perfluorooctane sulfonic acid is not detected in river water and river water samples, after the addition of 4.0umol/L, the RSD is 7.6-9.6%, and the recovery rate is 85.0-108%, indicating that the method is simple and rapid, high in sensitivity and good in repeatability, and also indicating that the method is strong in reliability and has a good linear range for determining perfluorooctane sulfonic acid.

Compared with the prior art, the invention has the following beneficial effects:

1) the method for measuring the perfluorooctane sulfonate by the toluidine blue probe dual-wavelength resonance Rayleigh scattering method has the advantages of simple and convenient operation, rapidness and good selectivity;

2) the method for measuring the perfluorooctane sulfonate by resonance scattering has the advantages of good linearity and high sensitivity;

3) the method for measuring the perfluorooctane sulfonate by resonance scattering has the characteristics of strong stability and low cost.

Drawings

FIG. 1 shows resonance Rayleigh scattering spectra (1-9 are respectively 0, 0.08, 0.04, 0.02, 2, 4, 6, 8, 10umol/L) corresponding to different concentrations of perfluorooctane sulfonate-toluidine blue system

FIG. 2 is a linear plot of different perfluorooctanesulfonic acids and Δ I

FIG. 3 is a transmission electron micrograph of different systems (a: toluidine blue; b: toluidine blue + perfluorooctane sulfonic acid)

Detailed Description

Examples of the method for detecting perfluorooctane sulfonate by resonance rayleigh scattering of the present invention and applications thereof are as follows, but the present invention is not limited thereto at all.