CN115201176A - A kind of detection method of trivalent antimony - Google Patents

Abstract

The invention discloses a detection method for trivalent antimony. The method comprises: using an Au@Ag thin film modified with organic functional groups as a base material for detecting trivalent antimony based on surface-enhanced Raman spectroscopy. In this method, Au@Ag core-shell structure nanoparticles are synthesized, Au@Ag thin films are prepared by self-assembly arrangement method, and Au@Ag-DTT thin film substrates are obtained by modification with organic functional groups. Sb(III) was specifically enriched on the surface of Au@Ag‑DTT thin films by dropping or soaking, and the Raman characteristic peaks of Sb(III) were observed by a portable Raman spectrometer. The sample preparation method and the target pollutant analysis method adopted in the present invention are easy to operate, and can realize the rapid detection of Sb(III) in the environmental matrix.

Description

A kind of detection method of trivalent antimony

technical field

The invention relates to the technical field of element detection and analysis, in particular to a detection method for trivalent antimony.

Background technique

Antimony (Sb) is a typical oxygen-containing anion pollutant, which is ubiquitous in the atmosphere, soil, rock, water and other natural environments. The entry of antimony into the environment threatens the survival and health of human beings. Antimony is currently considered a priority pollutant by the European Union (EU) and the US Environmental Protection Agency (EPA). The World Health Organization (WHO), EPA, EU and the Chinese Ministry of Health have all put forward clear requirements for the concentration of antimony in drinking water. 5μg/L, Japan is 2μg/L, China's "Drinking Water Hygiene Standard" GB5749-2006 stipulates that the concentration of antimony in drinking water should be lower than 5μg/L. Studying and monitoring the form and content of antimony in environmental media is of great significance to both environmental supervision and human health.

The main existing forms of antimony are trivalent antimony (Sb(III)), pentavalent antimony (Sb(V)) and organic antimony. The environmental toxicity and bioavailability of antimony are closely related to the occurrence forms. Most biologically toxic. In order to correctly assess the hazard of antimony in environmental samples, it is particularly important to establish effective separation and detection methods. Common antimony speciation methods in the laboratory include spectrophotometry, atomic absorption spectroscopy (AAS), atomic fluorescence spectroscopy (AFS), high performance liquid chromatography (HPLC), inductively coupled plasma-mass spectrometry (ICP-MS), etc. These methods The detection accuracy is high but the price is high, and the sample pretreatment method is highly required. Sb(III) is easily oxidized in the process of environmental sample collection, storage, transportation, and pretreatment, which leads to biased evaluation of environmental sample toxicity. Therefore, exploring an economical, rapid and efficient Sb(III) on-site rapid analysis technique is the key to the field of environmental analysis.

Surface-enhanced Raman spectroscopy has attracted attention in the environmental field because of its non-destructive and rapid advantages, which provides a direction for the establishment of a rapid on-site analysis method for Sb(III). In 1928, Indian physicist Raman discovered the Raman scattering effect. In 1974, Fleischmann et al. first observed the Surface Enhanced Raman Scattering (SERS) phenomenon of pyridine on rough silver electrodes. Single-molecule detection has been achieved, and SERS has been widely used in adsorbate interface orientation and configuration, conformational research and structural analysis. At present, SERS has been studied in the detection of organic pollutants such as dyes and pesticides, and inorganic pollutants such as Hg and As, but there are few reports on SERS in the field of Sb speciation analysis at home and abroad. Panarin et al. added phenylfluorescein (PhF) to the Sb-containing solution, and detected the specific stretching vibration peaks of the Sb-PhF complex by SERS (Applied Spectroscopy 2014, 68, (3), 297-306.); Wen et al. The I ₃ ^- -Ag-royce blue B(VBB) system indirectly detects Sb(III). The principle is that when VBB is complexed with I ₃ ^- the Raman signal of VBB is low, and SbH ₃ reduces I ₃ ^- to I ^- to release VBB and establish VBB Linear relationship of Raman signal to Sb(III) concentration (Food Chemistry 2017, 214, 25-31.). The existing SERS detection methods are all indirect detection of Sb(III), and the detection limit, sensitivity, stability, and anti-interference are all difficult to meet the requirements of environmental applications.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method for detecting trivalent antimony. By selecting a stable substrate material with good enhancement effect on surface-enhanced Raman spectroscopy and strong response selectivity to trivalent antimony, the method improves the operational simplicity of the SERS detection method, has high sensitivity and strong stability, and can rapidly detect trivalent antimony .

For achieving the above object, the present invention is as follows:

A method for detecting trivalent antimony, the method comprising:

Au@Ag thin films modified with organic functional groups were used as substrates for the detection of trivalent antimony based on surface-enhanced Raman spectroscopy.

Preferably, the organic functional group modified Au@Ag film is prepared by the following steps:

Synthesis of Au nanoparticles;

Synthesis of Au@Ag nanoparticles;

Preparation of Au@Ag thin film materials;

Modification of Au@Ag thin films with organic functional groups.

Preferably, the method for synthesizing Au nanoparticles is a reduction method.

Preferably, the method for synthesizing Au@Ag nanoparticles is a seed growth method.

Preferably, the method for preparing the Au@Ag thin film material is an interface self-assembly method.

Preferably, the organic functional group in the Au@Ag thin film material modified with organic functional groups is dithiothreitol (DTT).

Preferably, the instrument for detecting trivalent antimony by surface-enhanced Raman spectroscopy is a Raman spectrometer.

Preferably, the conditions for signal acquisition by the Raman spectrometer are that the laser wavelength is 785 nm, the scanning time is 6 s, and the number of integration times is 3.

The beneficial effects of the present invention are as follows:

The invention uses the Au@Ag film modified with DTT as the base material, realizes the specific binding of Sb(III), shortens the distance between Sb(III) and the surface of Au@Ag nanoparticles, and increases the Sb(III) ), the SERS enhancement effect is good, and the DTT-modified Au@Ag film is a stable substrate material with strong response selectivity to Sb(III), which creates conditions for the occurrence of surface-enhanced Raman scattering.

Description of drawings

In order to illustrate the implementation of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention, which are common in the art. As far as technical personnel are concerned, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1A is a transmission electron microscope photograph of Au@Ag nanoparticles prepared in Example 2;

1B is a photo of the Au@Ag thin film material prepared in Example 3;

Figure 2 shows the SERS response intensities of different concentrations of Sb(III) on Au@Ag-DTT films during detection;

Fig. 3 is the SERS spectrum of Sb(III) in the presence of environmental interfering ions;

Figure 4 is a schematic diagram of the effect of Au@Ag-DTT film on the uniformity of Sb(III) detection.

Detailed ways

The embodiments of the present invention will be described in further detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict.

Because the existing SERS detection methods are all indirect detection of Sb(III), and the detection limit, sensitivity, stability, and anti-interference are all difficult to meet the requirements of environmental applications. The invention provides a rapid detection method for trivalent antimony. The method is based on surface-enhanced Raman spectroscopy technology. Au nanoparticles are first synthesized by a reduction method, and then Au@Ag core-shell structure particles are synthesized by a seed growth method. The Au@Ag thin film was prepared by the self-assembly arrangement transfer method at the inorganic interface, and finally the surface of the Au@Ag thin film was modified by DTT. The enrichment of Sb(III) on the surface of Au@Ag-DTT films was achieved by dropping or soaking method, and the Raman characteristic peaks of Sb(III) were observed by a portable Raman spectrometer. A series of experiments prove that the sample preparation method and the target pollutant analysis method adopted in the present application are easy to operate, and can realize the rapid detection of Sb(III) in the environmental matrix solution.

A detection method of trivalent antimony, the method comprises the steps:

1. Synthesis of Au nanoparticles by reduction method:

_The Au nanoparticle sol was prepared by adding sodium citrate to the HAuCl solution at 120 °C for reduction reaction;

2. Synthesis of Au@Ag nanoparticles by seed growth method:

Au@Ag nanoparticles were prepared by adding ascorbic acid and AgNO ₃ to the Au nanoparticle sol;

3. Preparation of Au@Ag planar thin film materials by interfacial self-assembly method:

By slowly adding cyclohexane and rapidly adding ethanol into the Au@Ag nanoparticle solution, Au@Ag self-assembled and ordered at the organic-aqueous interface was formed. After the cyclohexane was completely volatilized, the Au@Ag self-assembled film was transfer;

4. Modification of Au@Ag thin film materials with organic functional groups:

DTT-modified Au@Ag thin films (Au@Ag-DTT thin films) were obtained by soaking the Au@Ag thin film material in dithiothreitol (DTT) ethanol solution;

5. Detection of trivalent antimony:

The solution containing trivalent antimony was added dropwise to the Au@Ag-DTT film, and a portable Raman spectrometer was used for signal acquisition. The laser wavelength was 785 nm, the scanning time was 6 s, and the integration times were 3 to obtain the SERS spectrum of trivalent antimony.

In the present invention, Au@Ag core-shell structure nanoparticles are synthesized first. Au and Ag are the most commonly used SERS active substrates in surface-enhanced Raman spectroscopy. Ag has better Raman enhancement effect, and Au has stronger stability. Ag particles utilize both the stable spherical structure of Au and the Raman enhancement effect of Ag; the synthesized Au@Ag particles are prepared into a 2D thin film structure to prevent the agglomeration of nanoparticles and inactivation during sample measurement; by comparing various organic functional groups , it is found that the Au@Ag film modified with DTT can achieve specific binding to Sb(III), shorten the distance between Sb(III) and the surface of Au@Ag nanoparticles, and increase the Raman scattering of Sb(III) The cross section creates the conditions for the occurrence of surface-enhanced Raman scattering.

The present application will be described below through specific embodiments.

Example 1

Preparation of Au Nanoparticles:

Add 2 mL of 2% HAuCl ₄ solution to 46 mL of deionized water, and stir at 700 rpm on a magnetic stirrer under heating at 120 °C. When the temperature rises to 120 °C, continue stirring for 2 min, and then add 2 mL of 100 mg lemon to the above solution. Sodium solution. The reaction was continued for 20 min, heating was stopped, and the product was cooled to room temperature with stirring to obtain Au nanoparticle sol.

Example 2

Preparation of Au@Ag nanoparticles:

Add 1-5 mL of the obtained Au nanoparticle sol into 15 mL of deionized water, stir with a magnetic stirrer at 400 rpm for 5 min at room temperature at 25°C, add 1.0-1.5 mL of 10 mM ascorbic acid solution and continue stirring for 1 min, and then add one drop every 20 s. Add 0.5-1.0 mL of 10 mM AgNO ₃ solution, and continue stirring for 20 min under dark conditions; Figure 1A is a transmission electron microscope photo of the Au@Ag nanoparticles prepared in Example 2. Figure 1A shows that the nanoparticles prepared in this example are For the core-shell structure, the size is uniform, the average particle size is about 30nm.

Example 3

Preparation of Au@Ag-DTT thin film materials:

Slowly add 1-6 mL of cyclohexane to the obtained Au@Ag solution, and quickly add 1-6 mL of ethanol by injection. Au@Ag self-assembles and arranges in an orderly manner at the organic-water interface. After the cyclohexane is completely volatilized, the The Au@Ag self-assembled film was transferred to a clean silicon wafer, and finally the Au@Ag film on the silicon wafer was transferred to an ordinary scotch tape; Figure 1B is a photo of the Au@Ag film material prepared in Example 3.

Example 4

Preparation of DTT-modified Au@Ag thin films

The Au@Ag film material was immersed in 1-15mM dithiothreitol (DTT) ethanol solution, soaked for 30 min, washed with ethanol and air-dried; Figure 4 shows the uniformity of Sb(III) detection by Au@Ag-DTT film It can be seen from FIG. 4 that the signal of the Au@Ag-DTT film prepared in this example is stable when it is used for the detection of Sb(III).

Example 5

Rapid detection of trivalent antimony:

5 μL of the solution containing trivalent antimony was dropped onto the Au@Ag-DTT film, and a portable Raman spectrometer was used for signal acquisition. The laser wavelength was 785 nm, the scanning time was 6 s, and the number of integration times was 3, as shown in Figures 2 and 3. The SERS spectrum of trivalent antimony was obtained; Figure 2 shows the SERS response intensities of different concentrations of Sb(III) on the Au@Ag film during detection. It can be seen from FIG. 2 that the Au@Ag-DTT film used in the present invention can enrich Sb(III) on the surface of the substrate and produce a corresponding Raman enhancement effect. Figure 3 is the SERS spectrum of Sb(III) in the presence of environmental interfering ions. It can be seen from Figure 3 that the presence of interfering ions does not affect the detection of Sb(III), indicating that the present invention has the potential to be applied to actual sample detection.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Changes or changes in other different forms cannot be exhausted here, and all obvious changes or changes derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (8)

1. a detection method of trivalent antimony, is characterized in that, the method comprises: Au@Ag thin films modified with organic functional groups were used as substrates for the detection of trivalent antimony based on surface-enhanced Raman spectroscopy. 2. detection method according to claim 1, is characterized in that, the Au@Ag film of described organic functional group modification is made by following steps: Synthesis of Au nanoparticles; Synthesis of Au@Ag nanoparticles; Preparation of Au@Ag thin film materials; Modification of Au@Ag thin films with organic functional groups. 3. The detection method according to claim 2, wherein the method for synthesizing Au nanoparticles is a reduction method. 4. The detection method according to claim 2, wherein the method for synthesizing Au@Ag nanoparticles is a seed growth method. 5. The detection method according to claim 2, wherein the method for preparing the Au@Ag thin film material is interface self-assembly. 6 . The detection method according to claim 2 , wherein the organic functional group in the Au@Ag thin film material modified with an organic functional group is dithiothreitol. 7 . 7 . The detection method according to claim 1 , wherein the instrument for detecting trivalent antimony by surface-enhanced Raman spectroscopy is a Raman spectrometer. 8 . 8 . The detection method according to claim 7 , wherein the conditions for signal collection by the Raman spectrometer are: laser wavelength of 785 nm, scanning time of 6 s, and integration times of 3. 9 .

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