Preparation method and application of flexible transparent SERS substrate

Abstract

The invention discloses a preparation method and an application of a flexible transparent SERS substrate. The method comprises the following steps of heating an HAuCl4 water solution to be boiling under vigorous stirring, rapidly adding a citrate aqueous solution, and condensing and refluxing for 13-17 minutes after the color change of the solution is stable, stopping heating, and cooling to roomtemperature under stirring to obtain Au nano-sol; and adding the Au nano-sol into a beaker, and slowly injecting a mixed solution of n-hexane and ethanol into the Au nano-sol by using a needle cylinder syringe at room temperature, slowly forming two phases of water oil, wherein a layer of nanometer Au film is gradually formed at the water-oil interface, and after the oil phase naturally volatilizes, directly covering by using an adhesive tape for uncovering the single-layer nano Au on the water phase surface, removing residual gold sol on the surface of the adhesive tape by using deionized water to prepare the flexible transparent SERS substrate. By adoption of the technology, the Au nano-particles can have better distribution uniformity on an adhesive tape, the flexibility and the viscosity of the adhesive tape can be well maintained, direct measurement can be carried out by a laser backlight mode, and in-situ detection is realized.

Description

technical field

[0001] The invention relates to a preparation method and application of a flexible transparent SERS substrate. Background technique

[0002] Traditional SERS substrates, such as Ag, Au, and Pt metal electrodes, have the problems of difficult control of roughness and poor reproducibility; gold nanorods with adjustable aspect ratio, silver cubes and silver triangles with controllable size and other noble metal sol SERS Substrates have the problems of poor storage stability, inconvenient portability, and are susceptible to interference from external environments such as temperature, pH, ion concentration and other factors; hard SERS substrates such as metal island films, quartz, and silicon wafers, although the stability has been improved and portability, it is still difficult to carry out effective in-situ detection of the analyte on the irregular surface, and a certain solvent is required for extraction. Therefore, it is of great significance to prepare flexi...

Examples

Embodiment 1

[0027] Put 1g of HAuCl purchased on aladdin 4 4H 2 O (molecular weight 412) is configured into HAuCl with ultrapure water 4 (100 g / L) mother liquor for use, HAuCl in the mother liquor 4 The concentration is 2.43×10 -1 mol / L;

[0028] Preparation of Au MLF / Tape SERS substrate:

[0029] 1) Au sol preparation: using the classic frens method: the above prepared HAuCl 4 (100 g / L) mother liquor was diluted to a concentration of 0.1 g / L, and 100 mL of the diluted solution was placed in a three-neck flask, heated to boiling under vigorous stirring, and then quickly added (directly poured) 2 mL (10 g / L) sodium citrate aqueous solution, the color of the solution gradually changed from light yellow to wine red, after the color of the solution became stable, condensed and refluxed for 15 min, stopped heating, cooled to room temperature under stirring, and obtained 2.43×10 -4 mol / L Au nano-sol, and finally put the synthesized Au nano-sol in a 4°C refrigerator for later use;

[003...

Embodiment 2

[0033] Investigate the effect of malachite green concentration on SERS spectrum:

[0034] Prepare malachite green standard aqueous solution: concentrations are 0.05, 0.075, 0.1, 0.15, 0.2, 0.5, 1, 1.5, 2 and 4 μmol / L;

[0035] For the Au MLF / Tape SERS substrate prepared in Example 1, the malachite green standard aqueous solution prepared above was detected, and the detection results were as follows figure 2 as shown, figure 2 For malachite green 803 cm -1 The variation curve of characteristic peak intensity with concentration;

[0036] The detection conditions are as follows: use a 632.18 nm light source as the excitation light to suppress the fluorescence interference of the sample to be tested, the light energy range is 30-60 mW, and the integration time is 10 s. When performing SERS testing, first drop 0.4 ml of sample solution on the sample cell, cover the Au MLF / Tape substrate on the sample cell port, use a laser light source to irradiate through the substrate, and d...

Embodiment 3

[0042] Embodiment 3 investigates the impact of the volume of chloroauric acid on the SERS spectrum:

[0043] Take different volumes of HAuCl 4 (100 g / L) 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL and 0.8 mL, add ultrapure water to 100 mL in a three-necked flask. The concentration of the sodium citrate aqueous solution added therein is 20, 40, 60, 80, 160 g / L respectively, and other conditions are the same as the Au MLF / Tape SERS substrate of Example 1, for the malachite green standard aqueous solution with a concentration of 1 μmol / L Detect, detection method condition is with embodiment 2, and detection result sees Figure 4 ;

[0044] The density of gold nanoparticles on the water-oil interface can be controlled by adjusting the concentration of Au sol and the size of the cross-sectional area of ​​the container, and the concentration of Au sol can be controlled according to the volume of chloroauric acid added. When the volume of chloroauric acid added increases, the color of the gold...

technical field

[0001] The invention relates to a preparation method and application of a flexible transparent SERS substrate. Background technique

[0002] Traditional SERS substrates, such as Ag, Au, and Pt metal electrodes, have the problems of difficult control of roughness and poor reproducibility; gold nanorods with adjustable aspect ratio, silver cubes and silver triangles with controllable size and other noble metal sol SERS Substrates have the problems of poor storage stability, inconvenient portability, and are susceptible to interference from external environments such as temperature, pH, ion concentration and other factors; hard SERS substrates such as metal island films, quartz, and silicon wafers, although the stability has been improved and portability, it is still difficult to carry out effective in-situ detection of the analyte on the irregular surface, and a certain solvent is required for extraction. Therefore, it is of great significance to prepare flexi...

Examples

Embodiment 1

[0027] Put 1g of HAuCl purchased on aladdin 4 4H 2 O (molecular weight 412) is configured into HAuCl with ultrapure water 4 (100 g / L) mother liquor for use, HAuCl in the mother liquor 4 The concentration is 2.43×10 -1 mol / L;

[0028] Preparation of Au MLF / Tape SERS substrate:

[0029] 1) Au sol preparation: using the classic frens method: the above prepared HAuCl 4 (100 g / L) mother liquor was diluted to a concentration of 0.1 g / L, and 100 mL of the diluted solution was placed in a three-neck flask, heated to boiling under vigorous stirring, and then quickly added (directly poured) 2 mL (10 g / L) sodium citrate aqueous solution, the color of the solution gradually changed from light yellow to wine red, after the color of the solution became stable, condensed and refluxed for 15 min, stopped heating, cooled to room temperature under stirring, and obtained 2.43×10 -4 mol / L Au nano-sol, and finally put the synthesized Au nano-sol in a 4°C refrigerator for later use;

[003...

Embodiment 2

[0033] Investigate the effect of malachite green concentration on SERS spectrum:

[0034] Prepare malachite green standard aqueous solution: concentrations are 0.05, 0.075, 0.1, 0.15, 0.2, 0.5, 1, 1.5, 2 and 4 μmol / L;

[0035] For the Au MLF / Tape SERS substrate prepared in Example 1, the malachite green standard aqueous solution prepared above was detected, and the detection results were as follows figure 2 as shown, figure 2 For malachite green 803 cm -1 The variation curve of characteristic peak intensity with concentration;

[0036] The detection conditions are as follows: use a 632.18 nm light source as the excitation light to suppress the fluorescence interference of the sample to be tested, the light energy range is 30-60 mW, and the integration time is 10 s. When performing SERS testing, first drop 0.4 ml of sample solution on the sample cell, cover the Au MLF / Tape substrate on the sample cell port, use a laser light source to irradiate through the substrate, and d...

Embodiment 3

[0042] Embodiment 3 investigates the impact of the volume of chloroauric acid on the SERS spectrum:

[0043] Take different volumes of HAuCl 4 (100 g / L) 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL and 0.8 mL, add ultrapure water to 100 mL in a three-necked flask. The concentration of the sodium citrate aqueous solution added therein is 20, 40, 60, 80, 160 g / L respectively, and other conditions are the same as the Au MLF / Tape SERS substrate of Example 1, for the malachite green standard aqueous solution with a concentration of 1 μmol / L Detect, detection method condition is with embodiment 2, and detection result sees Figure 4 ;

[0044] The density of gold nanoparticles on the water-oil interface can be controlled by adjusting the concentration of Au sol and the size of the cross-sectional area of ​​the container, and the concentration of Au sol can be controlled according to the volume of chloroauric acid added. When the volume of chloroauric acid added increases, the color of the gold...

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