CN-121978091-A - Ascorbic acid detection method based on RGB colorimetric and gray analysis

Abstract

The invention discloses a dual-mode Ascorbic Acid (AA) detection method based on RGB colorimetric and gray analysis. Firstly, preparing nano silver sol, then uniformly mixing a certain volume of nano silver sol, ultrapure water, glycine-NaOH buffer solution and 0.2 mL of 0.01 mol/L AgNO 3 solution, and adding an ascorbic acid standard solution or a solution to be detected. And collecting a reaction system image by using a self-made device combined with the smart phone, and extracting a Tyndall effect average gray value (AG) and a color intensity value (RGB channel value) as dual response signals for quantitative analysis AA. The invention combines the smart phone RGB colorimetric method with the Tyndall effect gray level analysis method, realizes the rapid and sensitive detection of AA, has the advantages of high reliability, good selectivity, strong portability and the like, is suitable for POCT (point of care testing) on-site rapid detection, and is convenient for popularization and use.

Inventors

• ZHANG YUAN
• Zhai Jiangli
• WEI XIAOJIE
• CAO YABO
• LIU XINHUA
• LIU XIN
• YANG XIAOCHUN
• WANG LEI
• QI WENHAO

Assignees

• 唐山师范学院

Dates

Publication Date

20260505

Application Date

20260112

Claims (4)

1. 1. An ascorbic acid detection method based on RGB colorimetric and gray analysis is characterized by comprising the following steps: The preparation method comprises the steps of 1, uniformly mixing tea extracts with NaOH solution, adding AgNO 3 solution, reacting at room temperature for 10min to obtain nano silver sol, wherein the feeding ratio of the reaction is 1. 1 mL tea extracts to 0.25 mL of 0.1 mol/L NaOH solution and then to 1 mL of 1 mmol/L AgNO 3 solution, the tea extracts are obtained by adding 30 mL ultrapure water into 0.4 g tea leaves, stirring at room temperature for 30min, centrifuging and collecting supernatant, and diluting 1 part by volume of supernatant with 99 parts by volume of ultrapure water; Drawing a standard curve, namely uniformly mixing 50 mu L of nano silver sol, 1.25 mL ultrapure water, 0.5 mL of 0.1 mol/L pH 8.8 glycine-NaOH buffer solution and 0.2mL of 0.01 mol/L AgNO 3 solution, adding 0.5 mL ascorbic acid standard solutions with different concentrations, wherein the concentration range of the ascorbic acid standard solutions is 0-85 mu g/mL, reacting at room temperature for 10min, collecting an image of a reaction system, extracting sigma RGB and/or AG values of the shot image, wherein the sigma RGB is the sum of R, G, B three channel numerical values of the image, the AG value is the average gray value of the image, the ascorbic acid concentration is taken as an abscissa, the AG value and/or delta sigma RGB is taken as an ordinate, and drawing the standard curve, wherein the delta sigma RGB is the difference between the ascorbic acid concentration and the sigma RGB of the ascorbic acid standard solution with a certain concentration; And 3, measuring a sample to be measured, namely uniformly mixing 50 mu L of nano silver sol, 1.25 mL ultrapure water, 0.5 mL of 0.1 mol/L pH 8.8 glycine-NaOH buffer solution and 0.2 mL of 0.01 mol/L AgNO 3 solution, adding 0.5 mL solution to be measured, reacting at room temperature for 10min, collecting an image of a reaction system, extracting sigma RGB and/or AG values of the photographed image, and determining the concentration of ascorbic acid in the solution to be measured according to delta sigma RGB and/or AG values of the solution to be measured and the standard curve of the step 2.
2. 2. The method for detecting ascorbic acid based on RGB colorimetric and gray scale analysis according to claim 1, wherein in the step 2, only AG value of the reaction system is extracted, an ascorbic acid standard solution with concentration range of 0.1-85 mug/mL is adopted, the ascorbic acid concentration is taken as an abscissa, AG value is taken as an ordinate, and a standard curve is drawn, and in the step 3, only AG value of the reaction system of the solution to be detected is extracted, and the concentration of ascorbic acid in the solution to be detected is calculated according to the AG value standard curve.
3. 3. The method for detecting ascorbic acid based on RGB colorimetric and gray scale analysis according to claim 1, wherein in the step 2, only the sigma RGB value of the reaction system is extracted, an ascorbic acid standard solution with a concentration range of 0.5-85 mug/mL is adopted, an ascorbic acid concentration is used as an abscissa, and a delta sigma RGB value is used as an ordinate to draw a standard curve, in the step 3, only the sigma RGB value of the reaction system of the solution to be detected is extracted, the delta sigma RGB value is calculated, and the concentration of ascorbic acid in the solution to be detected is calculated according to the delta sigma RGB value standard curve.
4. 4. The method for detecting the ascorbic acid based on the RGB colorimetric and gray scale analysis according to the claim 1 is characterized in that in the step 2, AG and sigma RGB values of a reaction system are simultaneously extracted, delta sigma RGB values are obtained through calculation, an ascorbic acid standard solution with the concentration range of 0.5-85 mug/mL is adopted, the concentration of the ascorbic acid is taken as an abscissa, AG and delta sigma RGB values are taken as an ordinate respectively, two standard curves are drawn, in the step 3, AG and sigma RGB values of the reaction system of a solution to be detected are simultaneously extracted, delta sigma RGB values are obtained through calculation, quantitative analysis is carried out through the two standard curves respectively, and the concentration of the ascorbic acid in the solution to be detected is obtained through calculation.

Description

Ascorbic acid detection method based on RGB colorimetric and gray analysis Technical Field The invention relates to the field of chemical detection of ascorbic acid, in particular to a smart phone RGB colorimetric and Tyndall effect gray analysis dual-mode ascorbic acid detection method based on POCT (point of care testing). Background Ascorbic Acid (AA), namely vitamin C, is an essential nutrient for human bodies, and widely participates in the metabolic process of the human bodies, and foods and medicines rich in AA such as fruits, vegetables, VC beverages, VC tablets and the like are main sources for obtaining the AA by the human bodies. AA is chemically unstable and is subject to decomposition during processing, transportation and storage. The rapid and accurate detection of AA is significant for food industry, pharmaceutical analysis and clinical diagnosis. The AA detection method comprises a fluorescence method, an electrochemical method, a high performance liquid chromatography, a Raman spectrum method and the like, and generally has the limitations of expensive instruments and equipment, time consumption in a sample pretreatment process and the like. Colorimetric analysis method is developed rapidly due to the advantages of visual and visible result, simplicity, rapidness, low cost and the like, and becomes one of the main methods for measuring AA at present. Classical colorimetric assays typically rely on spectrophotometers and are therefore still limited to laboratory analysis. Compared with the traditional spectrophotometer, the intelligent mobile phone is used as an emerging detection tool, can collect digital images of samples in real time, extracts intensity parameters of color spaces such as red, green and blue primary colors (RGB) through mobile phone software, realizes sample color quantification, and has the advantages of portability and popularity. However, the method still faces a plurality of challenges in practical application, namely, the detection result is easily influenced by external factors such as ambient light conditions, background color of a sample and the like, the anti-interference capability is weak, the resolution capability of a mobile phone camera on the fine difference of the color is limited, the sensitivity of the method is limited, and the reliability of the detection result is insufficient due to a single output signal mode. In order to solve the defects of a single-mode colorimetric method in the aspects of anti-interference performance, sensitivity, reliability and the like, a dual-mode sensing technology integrating different detection principles is developed, and analysis performance is improved through a signal complementation and self-verification mechanism, so that the method has become an important strategy. Currently, researchers have constructed dual-mode sensors for AA detection, such as raman spectrum-colorimetric, fluorescence-colorimetric, and electrochemical-colorimetric. However, the methods still have the defects of dependence on large-scale precise instruments, complex synthesis of fluorescent probes, need to construct additional electrode systems and the like, and are difficult to meet the actual requirements of on-site rapid detection in the scenes of foods, medicines and the like. Therefore, finding a novel complementary signal which can be well adapted to a colorimetry of a smart phone and break through the bottleneck of sensitivity and anti-interference performance becomes a key for realizing the AA high-performance POCT. The tyndall effect has recently become a new signal readout mechanism of great interest in POCT field due to its high sensitivity characteristics as a classical colloidal light scattering phenomenon. The technology breaks through the sensitivity bottleneck of color resolution, the scattering signal can be accurately quantified by extracting the average gray value (AG) by the smart phone, the interference of the background color of the sample is avoided, expensive instruments are not needed, and the color matching method has good adaptability and complementarity with the smart phone colorimetric method. At present, the related research of combining a Tyndall effect gray level analysis method with a smart phone RGB colorimetric method for AA analysis has not been reported yet. In addition, the construction of a complete system suitable for on-site rapid detection, and the green and simple preparation of the nanoparticle with stable performance are also important technical preconditions. Green tea is rich in natural components such as tea polyphenol, tea polysaccharide and the like, can be used as a green reducing agent and a stabilizing agent to replace traditional chemical reagents such as NaBH 4, citric acid and the like for synthesizing nano particles. The plant reduction preparation method based on the green tea extract does not need to use aqua regia to soak glassware, does not need to carry out post-modification on the p