Method for stepwise detecting Cr(VI) and Cr(III) based on fluorescent carbon quantum dots

A carbon quantum dot, stepped technology, applied in the field of stepped detection of Cr and Cr based on fluorescent carbon quantum dots, can solve the problems of difficulty in rapid detection and daily detection, expensive instruments and equipment, and cumbersome detection process, and achieve excellent photoresistance. The effect of luminescence performance, simple method and wide detection range

Pending Publication Date: 2020-09-25
JIANGSU UNIV
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  • Abstract
  • Description
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Problems solved by technology

However, the results of spectrophotometric detection of chromium are less stable and have large errors; atomic absorption method can only detect the total chromium content; ICP-MS and ICP-OES have high detection sensitivity and can detect Cr(Ⅲ) and Cr(Ⅵ) respectively detection, but the detection process is cumbersome, the operation is complicated, and the equipment is expensive, which is difficult to meet the needs of on-site rapid detection and daily detection
Although the fluorescence detection method of heavy metals based on carbon quantum dots (CDs) has the advantages of simplicity, rapidity, and strong ability to resist environmental interference, the currently established method can only detect a single valence state of elements, and can only detect Cr(Ⅵ) in actual samples. content, but the Cr(Ⅲ) content in the sample cannot be detected

Method used

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  • Method for stepwise detecting Cr(VI) and Cr(III) based on fluorescent carbon quantum dots
  • Method for stepwise detecting Cr(VI) and Cr(III) based on fluorescent carbon quantum dots
  • Method for stepwise detecting Cr(VI) and Cr(III) based on fluorescent carbon quantum dots

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Embodiment 1: Preparation of fluorescent carbon quantum dots

[0038] (1) Dissolve 100 mg of ammonium citrate and 200 mg of bis-linked pinacol-based diborane (BPDB) in 5 mL of ultrapure water, mix well, and transfer to a PPL-lined hydrothermal autoclave , heated to 240°C, and kept for 10 h. After cooling to room temperature, a solution a containing pyrolysis products was obtained.

[0039] (2) The solution a obtained in step (1) was centrifuged at 8500 rpm for 10 min, and the sediment was discarded to obtain the supernatant. The supernatant was filtered through a 0.22 μm microporous membrane to obtain a transparent light yellow solution, which emitted blue fluorescence under a 365 nm ultraviolet light, which was the stock solution of the CDs solution, and was stored at 4°C for later use.

[0040] (3) Dilute the stock solution of CDs solution with ultrapure water to a final concentration of 10 mg / L for later use.

[0041] (4) Using quinine sulfate dihydrate (QY=54%, 3...

Embodiment 2

[0045] Example 2: Construction of a fluorescence detection system

[0046] (1) At room temperature, mix 100 µL of the CDs solution prepared in Example 1 with 900 µL of ultrapure water to obtain a mixed system, and the concentration of the CDs solution in the mixed system is 10 mg / L.

[0047] After the mixed system was left to stand for 10-30 min, the fluorescence peak intensity of the solution was detected by a fluorescence spectrophotometer at an excitation wavelength of 335 nm, recorded as .

[0048] (2) Prepare 10 mg / L Cr(Ⅵ) standard stock solution and 10 mg / L Cr(Ⅲ) standard stock solution, then mix the standard stock solution with ultrapure water to prepare different concentrations of Cr(Ⅵ) and Cr( Ⅲ) mixed solution, set aside.

[0049] (3) Mix 100 µL of CDs solution with 800 µL of different concentrations of Cr(Ⅵ) and Cr(Ⅲ) mixtures and 100 µL of ultrapure water to obtain a mixed system. The concentration of CDs solution in the mixed system was 10 mg / L, and the final ...

Embodiment 3

[0059] Example 3: Stepwise detection of Cr(Ⅵ) and Cr(Ⅲ) content and verification

[0060] Add a mixed solution of Cr(VI) and Cr(III) to the ultrapure water sample, so that the final concentrations of Cr(VI) and Cr(III) are both 100 μM, and use the fluorescence detection system established in Example 2 to detect Test samples and calculate the content of Cr(Ⅵ) and Cr(Ⅲ).

[0061] The calculated Cr(Ⅵ) and Cr(Ⅲ) contents were 104.2±5.1 μM and 98.7±6.5 μM, respectively, and the test results proved that the established method above could be used for the detection of Cr(Ⅵ) and Cr(Ⅲ) in ultrapure water. ) for step detection.

[0062] According to the 3σ / k principle (where σ represents the standard deviation obtained from 11 repeated detections of the blank solution, and k represents the slope of the standard curve), the detection limit (LOD) of this fluorescence detection system is 0.24 μM, which is much lower than that of other hexavalent Chromium detection method.

[0063] In thi...

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Abstract

The invention provides a method for stepwise detecting Cr(VI) and Cr(III) based on fluorescent carbon quantum dots, and belongs to the field of heavy metal detection. According to the method, the fluorescent carbon quantum dots are prepared firstly, then a fluorescent system is constructed to inspect the function relationship between the Cr(VI) content and the Cr(III) content and the fluorescenceintensity change value, and then the Cr(VI) content and the Cr(III) content are obtained by comparing the fluorescence intensity; the method is simple and convenient to operate, low in cost, wide in detection range and high in precision, can realize rapid stepped detection research on Cr (VI) and Cr (III), and has very important practical significance for detecting chromium elements with differentvalence states in drinking water and maintaining food safety.

Description

technical field [0001] The invention belongs to the technical field of heavy metal detection, and in particular relates to a stepwise detection method for Cr(III) and Cr(VI) based on fluorescent carbon quantum dots. Background technique [0002] Chromium metal mainly exists in two forms of Cr(Ⅲ) and Cr(Ⅵ). Among them, Cr(Ⅲ) is an essential trace element for the human body. Adequate intake can promote the body's lipid metabolism and reduce the content of cholesterol and triglycerides. Excessive intake will cause poisoning symptoms; Cr(VI) is highly toxic, and ingestion of Cr(VI) may cause gastric cancer, liver cancer and other diseases. At present, the harmfulness of the detected object is mainly measured by detecting the total chromium content, but this will cause the beneficial component Cr(Ⅲ) in the detected object to be mistaken as a harmful component. Therefore, when Cr(III) and Cr(VI) exist at the same time, it is necessary to detect the specific content of the two val...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/64C09K11/65C01B32/15B82Y40/00B82Y30/00
CPCG01N21/643C09K11/65C01B32/15B82Y30/00B82Y40/00G01N2021/6432
Inventor 石吉勇王月影邹小波胡雪桃李文亭黄晓玮李志华
Owner JIANGSU UNIV
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