Search

CN-118109192-B - Method for detecting nitrite ions by using sensitive fluorescent sensor

CN118109192BCN 118109192 BCN118109192 BCN 118109192BCN-118109192-B

Abstract

The invention discloses a method for detecting NO 2‑ in a ham sausage sample by a sensitive fluorescent sensor, belonging to the field of analysis and detection. The method comprises the steps of 1, preparing a carbon point by taking citric acid and corset as precursors, 2, quenching fluorescence by adding NO 2‑ in the carbon point through dynamic quenching and diazotization effects, constructing a standard curve of the concentration of NO 2‑ and the degree of fluorescence quenching based on the carbon point, and obtaining the concentration of NO 2‑ in a ham sausage sample. The invention quantitatively detects NO 2‑ substances by using the sensitive fluorescence sensor for the first time, has simple operation, safety and high efficiency, and is suitable for routine analysis.

Inventors

  • ZHU CHUN
  • LIU ZHAOCHEN
  • CHEN GUOQING
  • WU YAMIN
  • MA CHAOQUN
  • LI LEI
  • Gu jiao
  • GAO HUI

Assignees

  • 江南大学

Dates

Publication Date
20260505
Application Date
20240131

Claims (8)

  1. 1. A fluorescence sensor for detecting nitrite ions, said fluorescence sensor being prepared by: Mixing citric acid, corydaline and water, performing high-temperature reaction to prepare a crude carbon dot solution, centrifuging the crude carbon dot solution, filtering to remove unreacted particles, and finally performing dialysis and purification to obtain the fluorescent sensor.
  2. 2. The fluorescence sensor according to claim 1, wherein the mass ratio of citric acid to corydaline is 8-12:1, and the mass ratio of citric acid to water is 1:8-12.
  3. 3. The fluorescence sensor according to claim 1, wherein the high temperature reaction is at 180-200 ℃ for 6-8 hours.
  4. 4. The fluorescence sensor according to claim 1, wherein said detecting nitrite ions is detecting nitrite ion concentration in an aqueous environment or a meat processed food.
  5. 5. A method for detecting NO 2 - with a fluorescence sensor, comprising the steps of: (1) Preparing NO 2 - standard solutions with different concentrations, uniformly mixing the NO 2 - standard solution with a fluorescence sensor solution, adding the mixture into an HCl/NaOH buffer solution with pH of 2.5-3.5 to obtain a sample solution, incubating for a period of time, and then performing fluorescence spectrum detection, wherein the fluorescence sensor solution is obtained by diluting a fluorescence sensor according to any one of claims 1-3, the concentration of the fluorescence sensor solution is 0.001-0.005 g/mL, the volume ratio of the fluorescence sensor solution to the NO 2 - standard solution is 1:0.8-1.2, and the volume ratio of the fluorescence sensor solution to the HCl/NaOH buffer solution is 1:8-12; (2) Constructing a linear model of fluorescence quenching degree F 0 /F and NO 2 - concentration according to the change of fluorescence intensity before and after NO 2 - is added; (3) And (3) mixing the sample solution to be detected with the fluorescent sensor solution, adding the mixture into an HCl/NaOH buffer solution with pH of 2.5-3.5, incubating for a period of time, performing fluorescence spectrum detection, and obtaining the concentration of NO 2 - in the sample to be detected according to the linear model in the step (2).
  6. 6. The method according to claim 5, wherein in the steps (1) and (3), the incubation time is 5 to 8 hours.
  7. 7. The method according to claim 5, wherein in the step (1) and (3), the condition for detecting the fluorescence spectrum is that the fluorescence spectrum is detected by a fluorescence spectrometer, the width of an excitation slit and an emission slit of the spectrometer is 3.0nm, the integration time is 0.1s, the excitation wavelength of the fluorescence spectrometer is 402nm, the emission wavelength is 420nm-600nm, and the step length is 1nm.
  8. 8. The method of claim 5, wherein in step (3), the sample to be tested comprises a meat processed food and ambient water; When the sample to be measured is meat processed food, the preparation of the sample solution to be measured comprises the steps of obtaining meat processed food, mashing the meat processed food into meat paste, adding water and 0.5-1M KOH solution for mixing, then carrying out water bath for 3-5 min at 60-80 ℃, finally carrying out centrifugal filtration, and taking supernatant to obtain the sample solution to be measured.

Description

Method for detecting nitrite ions by using sensitive fluorescent sensor Technical Field The invention relates to a method for detecting NO 2- by a sensitive fluorescent sensor, belonging to the field of analysis and detection. Background Nitrite ion (NO 2-) is one of the most common nitrogen-containing compounds in life, and foods with high moisture content are not usually easy to preserve before the invention of refrigeration technology, thus causing deterioration of foods and preventing use, but in about 10 centuries in the metric year, there is improvement of the storage time of meat products by adding niter to the meat products, after which NO 2- is widely used in people's food life. Nitrite is widely used as a food additive in the modern food industry in prepared foods to enhance characteristic colors, improve flavor and inhibit bacterial growth. However, excessive nitrite intake can lead to the formation of deleterious nitrosamine substances that react with amides in the human body and combine with hemoglobin to induce methemoglobin to reduce oxygen transport capacity in the human body. Nitrite is normally used in an amount of not more than 30mg/kg. Therefore, the detection of NO 2- in food has great research significance for protecting the health of human bodies and preventing excessive nitrite from being eaten by mistake. In recent years, various analytical methods for detecting NO 2- have been developed, mainly high performance liquid chromatography, electrochemical methods, chemiluminescent methods, etc., which have problems of poor selectivity, high toxicity, low sensitivity, complicated operation, etc., although they have high accuracy and reliability. Therefore, there is an urgent need to find a simpler, faster, and more sensitive method for detecting NO 2-. Fluorescence-based detection is receiving increasing attention due to its low cost, ease of use, and high sensitivity and specificity. Among available fluorescent materials, carbon dots are excellent choices because of their ease of synthesis and surface modification, excellent biocompatibility, tunable emission wavelength, excellent light stability, and high fluorescence quantum yield. Interactions between the carbon dots and the analyte induce changes in the fluorescent properties of the carbon dots, such as intensity, wavelength, and lifetime, thereby generating a plurality of signals for selective and sensitive monitoring of the analyte. Therefore, there is still a great room for research on the synthesis of carbon dots and the construction of green fluorescent probes. Disclosure of Invention Technical problem Various analysis methods for detecting nitrite ions developed at present mainly comprise high performance liquid chromatography, electrochemical methods, spectrophotometry and the like, and the methods have the problems of poor selectivity, high toxicity, low sensitivity, complex operation and the like. Meanwhile, the report of detecting NO 2- in food by using a fluorescence sensing technology is few and the sensitivity and the detection limit are not advantageous compared with the traditional method. Technical proposal The invention provides a preparation method of a sensitive fluorescence sensor, which comprises the following steps: Mixing citric acid, corydaline and water, performing high-temperature reaction to prepare a crude carbon dot solution, centrifuging the crude carbon dot solution, filtering to remove unreacted particles, and finally performing dialysis and purification to obtain the fluorescent sensor. Further, the mass ratio of the citric acid to the corydaline is 8-12:1. Further, the mass ratio of the citric acid to the water is 1:8-12. Further, the high temperature reaction is carried out for 6-8 hours at 180-200 ℃. Further, a microporous membrane of 0.22. Mu.M was used for centrifugation. Further, the molecular weight cut-off in dialysis was 1000Da. The invention provides the sensitive fluorescent sensor prepared by the method. The sensitive fluorescent sensor provided by the invention is applied to the nitrite ion detection field. Further, the application refers to detection of nitrite ions in water environment and meat processed food. The invention provides a preparation method of a sensitive fluorescence sensor for detecting nitrite ions, which comprises the following steps: Mixing citric acid, corydaline and water, performing high-temperature reaction to prepare a crude carbon dot solution, centrifuging the crude carbon dot solution, filtering to remove unreacted particles, and finally performing dialysis and purification to obtain the fluorescent sensor. Further, the mass ratio of the citric acid to the corydaline is 8-12:1. Further, the mass ratio of the citric acid to the water is 1:8-12. Further, the high temperature reaction is carried out for 6-8 hours at 180-200 ℃. Further, a microporous membrane of 0.22. Mu.M was used for centrifugation. Further, the molecular weight cut-off in dialysis was 1000Da. Th