CN113533285B - Method for simply and rapidly detecting CTAB - Google Patents

Abstract

The invention provides a simple and rapid CTAB detection method, which uses nucleus to fix redAs a stabilizer, AgNO₃And NaBH₄And preparing AgNCs by adopting a chemical reduction method as a reaction reagent. AgNCs show strong fluorescence emission at 500nm upon 370nm excitation. Research shows that when Cetyl Trimethyl Ammonium Bromide (CTAB) is added into the AgNCs solution, the fluorescence intensity of the AgNCs is effectively quenched, and when the CTAB concentration is in the range of 0.01-1.0 mmol/L, the fluorescence intensity reduction degree of the silver nano-cluster and the fluorescence intensity reduction degree thereof show a good linear relation, and the detection limit is 6.1' 10^‑9 mol/L。

Description

Method for simply and rapidly detecting CTAB

Technical Field

The invention belongs to the field of chemical industry, and particularly relates to AgNO with nuclear red fixation as a stabilizer₃And NaBH₄And preparing AgNCs by adopting a chemical reduction method as a reaction reagent. And is applied to the detection of Cetyl Trimethyl Ammonium Bromide (CTAB).

Background

Noble metal nanoclusters exhibit distinctive optical, electrical, and chemical properties due to quantum size effects and small size effects, and thus have become one of the hot spots in the field of nanomaterial research in recent years. The small size, non-toxicity, light stability and the like of the fluorescent probe enable the fluorescent probe to have wide application prospects in the fields of chemical detection, biological labeling, catalysis and the like. At present, a plurality of methods for synthesizing the silver nanoclusters include a chemical reduction method, a photoreduction method, a template method, a radiation method, an ultrasonic method, a reversed-phase microemulsion method and the like, and the synthesis efficiency, the reproducibility, the stability and the like of the synthesis methods are still to be further improved. The detection of CTAB has important significance in the fields of environment and the like.

Disclosure of Invention

The invention aims to use the nuclear fast red as a stabilizer, AgNO₃And NaBH₄And preparing AgNCs by adopting a chemical reduction method as a reaction reagent. And is applied to the detection of CTAB. The method has the advantages of high efficiency, good reproducibility and stability of the synthesized AgNCs, and the like, and is convenient for large-scale synthesis. The detection sensitivity of the CTAB detection reagent is high.

To achieve the above object, the embodiments of the present invention are: a simple and rapid CTAB detection method comprises the following steps:

(1) using nuclear fast red as stabilizer, AgNO₃And NaBH₄And preparing AgNCs by adopting a chemical reduction method as a reaction reagent.

(2) Cetyl Trimethyl Ammonium Bromide (CTAB) is added into the AgNCs solution, the fluorescence intensity of the AgNCs is effectively quenched, when the CTAB concentration is in the range of 0.01-1.0 mu mol/L, the fluorescence intensity reduction degree of the silver nanoclusters presents a good linear relation with the CTAB concentration, and the detection limit is 6.1 multiplied by 10^-9mol/L. Thus, a simple and rapid method for detecting CTAB was established.

In step (1), AgNO is used₃Solution, nuclear fast red, and NaBH₄Respectively at a concentration of 1.0X 10^-4M、1.0×10^{- 3}M、1.5M。

In step (2), the optimal pH of the detection medium is 4.35.

Optimized is that the synthesized silver nanocluster AgNO₃The concentration in the synthesis solution was 1.0X 10^-4M; the concentration of the nuclear fast red in the whole synthetic solution is 1.0X 10^-3M；NaBH₄The concentration in the entire synthesis solution was 1.5M; the optimal reaction time for synthesizing the water-soluble fluorescent silver nanoclusters is 4 hours.

The fluorescence emission wavelength of the water-soluble fluorescent silver nanocluster synthesized by the method is 490-500 nm, the excitation wavelength is 370nm, and the average particle size of the nanocluster is 1.4 nm.

The method of the invention only needs to add AgNO₃Solution, nuclear fast red, and NaBH₄The method has the advantages of simple reaction system, simple operation, low cost and convenient large-scale synthesis.

Drawings

FIG. 1 is a fluorescence spectrum of water-soluble fluorescent silver nanoclusters synthesized by the embodiment of the present invention;

FIG. 2 is a Transmission Electron Microscope (TEM) and lattice characterization image of water-soluble fluorescent silver nanoclusters according to an embodiment of the present invention.

FIG. 3 is a fluorescence emission spectrum of AgNCs in the presence of CTAB at different concentrations.

FIG. 4 shows the change Deltal in fluorescence intensity of AgNCs_FLinear dependence on CTAB concentration.

Detailed Description

The present invention is described in further detail below with reference to specific experimental examples.

(1) Preparation of the solutions used:

preparation of a nuclear fast red solution: accurately weighing solid red 0.0357g of solid core to prepare 1.0 × 10^-3The solution of mol/L is used as mother liquor, and the solution is diluted to the required concentration when in use.

AgNO₃Preparation of the solution: accurately weighing AgNO₃0.0849g of solid, prepared into AgNO with a concentration of 0.01mol/L₃The solution was diluted to the desired concentration for use, using 50mL of the solution as the mother liquor.

NaBH₄Preparing a solution: 0.7566g of NaBH was weighed accurately₄The solid is prepared into 0.8mol/L solution which is used as mother liquor, and the solution is diluted to the required concentration when in use.

Preparing a NaOH solution: accurately weighing 2.0g of NaOH solid to prepare 0.2mol/L stock solution.

B-R buffer solution preparation: 0.6183g of boric acid is accurately weighed in a beaker, the boric acid is fully dissolved by secondary water, 0.57mL of acetic acid and 0.685mL of phosphoric acid are sequentially added in another beaker, proper amount of water is added for even mixing, and the solution in the two beakers is transferred to a 250mL volumetric flask for constant volume, namely 0.04mol/L of triacidic acid solution is prepared. Respectively putting a certain volume of the triacid solution into a volumetric flask, and then adding 0.2mol/L NaOH aqueous solution with different volumes into the volumetric flask according to the B-R buffer solution preparation proportion to prepare the B-R buffer solution with the required pH value.

(2) Preparing water-soluble fluorescent silver nanoclusters:

in a 50mL beaker was first added 2.0mL of 1.0X 10^-4mol/LAgNO₃Adding 3.0ml of 1.0X 10^{- 3}And adding 13.0mL of distilled water after fully shaking the mol/L nuclear solid red solution, and finally adding 2.0mL of 0.8mol/L sodium borohydride solution. After 4 hours of reaction at 40 ℃, the solution was observed to fade to colorless and then gradually turn to golden yellow.

(3) The optimization process of the synthesis condition of the water-soluble fluorescent silver nanocluster comprises the following steps:

the influence of the concentration of each substance (final concentration in the synthesis solution) on the fluorescence of the synthesized silver nanoclusters is mainly examined from the relative strength of the fluorescence intensity of the synthesized silver nanoclusters.

The preparation conditions of AgNCs are optimized by a controlled variable method. A series of optimization is respectively carried out on silver nitrate concentration, sodium borohydride concentration, nuclear solid red concentration, reaction time and reaction temperature.

According to the experimental result, the reactant concentration has certain influence on the fluorescence intensity of the prepared AgNCs, and when the nuclear solid red concentration is 1.0 multiplied by 10^-4mol/L, silver nitrate concentration of 1.0X 10^-5When the mol/L concentration of the sodium borohydride is 0.08mol/L, the prepared silver nanocluster has the strongest fluorescence intensity. This is probably because, under these conditions, the nuclear fast red stabilizes the Ag atoms to the maximum extent, preventing them from agglomerating, and thus achieving the effect of maximum fluorescence.

In addition, the reaction time and reaction temperature for the preparation of AgNCs were also explored herein. From the experimental results, it is understood that the fluorescence intensity of the AgNCs prepared is the strongest when the reaction temperature is 40 ℃. Probably because too high or too low a temperature affects the stabilization of the Ag atoms by the nuclear fast red. AgNCs with the strongest fluorescence intensity can be obtained when the reaction time is 4 hours, which is probably because Ag atoms are partially agglomerated after a period of time after the preparation of the AgNCs, thereby reducing the fluorescence intensity of the AgNCs.

(4) Condition optimization for CTAB detection

The fluorescence reduction degree delta I of the reaction of AgNCs and CTAB under different pH values (1.81-5.72) is researched_F. As is clear from the results of the experiment, the degree of decrease in fluorescence (. DELTA.I) at pH 4.35 was observed_FThe highest value is reached. Therefore, the optimum reaction pH was selected to be 4.35.

The reaction time also has certain influence on the detection of CTAB by AgNCs. The results show that the fluorescence intensity Δ I changes with increasing reaction time_FGradually increased and stabilized at 10 min. Therefore, we chose the optimal reaction time to be 10 min.

The experiment is in the range of 4-80 ℃, and the reaction temperature is exploredThe influence of CTAB on the detection of AgNCs, and it is apparent from the graph that the decrease Δ I in the fluorescence intensity of AgNCs is observed at 30 ℃_FTo a maximum. It is possible that the stability of AgNCs is destroyed after the temperature is increased, thereby influencing the detection of CTAB by AgNCs.

FIG. 1 is a spectrum diagram of the fluorescence spectrum of the synthesized water-soluble fluorescent nanocluster. As can be seen from FIG. 1, the fluorescence emission wavelength is about 500nm, and the excitation wavelength is 370 nm. The transmission electron microscope characterization result of the prepared water-soluble fluorescent nanocluster is shown in fig. 2.

As can be seen from FIG. 2, the prepared silver nanoclusters have a small particle size, an average particle size of 1.4nm and good dispersion. The high resolution transmission electron microscope result (shown in figure 2) shows that the synthesized nano-particle has the lattice distance of

Corresponding to the Ag (102) lattice.

FIG. 3 is a graph showing that silver nanoclusters are prepared under optimal experimental conditions, and the relationship between the fluorescence intensity of the silver nanoclusters and CTAB at different concentrations is detected by a fluorescence spectrophotometer. As shown in FIG. 3, the fluorescence intensity of silver nanoclusters gradually decreases as CTAB concentration increases. As shown in FIG. 4, when the CTAB concentration is in the range of 0.01-1.0. mu. mol/L, the concentration of CTAB and the change value Δ I of fluorescence intensity of the system_F(the difference value of the fluorescence of the blank group system and the fluorescence of the system after CTAB is added) is in a linear relation, and a linear regression equation delta I of the difference value is obtained_F47.69+447.5c (c is CTAB concentration, μmol/L), the correlation coefficient is 0.9945, and the detection limit (3 σ/k, where σ is the standard deviation of the blank sample and k is the slope of the standard curve) for this method was calculated to be 6.1 × 10^{- 9}mol/L。

It should also be noted that the particular embodiments of the present invention are provided for illustrative purposes only and do not limit the scope of the present invention in any way, and that modifications and variations may be made by persons skilled in the art in light of the above teachings, but all such modifications and variations are intended to fall within the scope of the invention as defined by the appended claims.

Claims (9)

1. A simple and rapid CTAB detection method is characterized by comprising the following steps:

(1) using nuclear fast red as stabilizer, AgNO₃And NaBH₄Preparing AgNCs by adopting a chemical reduction method as a reaction reagent;

(2) cetyl Trimethyl Ammonium Bromide (CTAB) is added into the AgNCs solution, the fluorescence intensity of the AgNCs is effectively quenched, when the CTAB concentration is in the range of 0.01-1.0 mu mol/L, the fluorescence intensity reduction degree of the silver nanoclusters presents a good linear relation with the CTAB concentration, and the detection limit is 6.1 multiplied by 10^-9mol/L。

2. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein AgNO is used in the step (1)₃Solution, nuclear fast red, NaBH₄Respectively at a concentration of 1.0X 10^-4M、1.0×10^-3M、1.5M。

3. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein the reaction time for preparing the silver nanoclusters is 4 h.

4. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein the optimal reaction temperature for preparing the silver nanoclusters is 40 ℃.

5. The simple and rapid CTAB detection method as claimed in claim 1, wherein the optimal fluorescence emission wavelength of the silver nanoclusters prepared by the method is 490-500 nm, the optimal excitation wavelength is 370nm, and the average particle size is 1.4 nm.

6. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein the optimum pH for detection is 4.35.

7. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein the reaction time after adding CTAB is 10 minutes.

8. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein the optimal temperature for detection is 30 ℃.

9. The method for simply and rapidly detecting CTAB as claimed in claim 1, wherein the concentration of CTAB to be detected is in the range of 0.01-1.0 μmol/L.

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