Method for detecting content of carbaryl in food by combining liquid phase micro-extraction with thread microfluid colorimetry

A colorimetric, carboxylate technology, which is used in measuring devices, material analysis, instruments, etc. by observing the effect on chemical indicators, to achieve the effect of simple and fast operation process, less sample required, and rapid detection.

Inactive Publication Date: 2020-05-22
SHANXI AGRI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the results of the above detection methods are sensitive and accurate, there is still room for improvement in detection equipment, sample preparation methods, etc.

Method used

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  • Method for detecting content of carbaryl in food by combining liquid phase micro-extraction with thread microfluid colorimetry
  • Method for detecting content of carbaryl in food by combining liquid phase micro-extraction with thread microfluid colorimetry
  • Method for detecting content of carbaryl in food by combining liquid phase micro-extraction with thread microfluid colorimetry

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] Embodiment 1, cotton thread pretreatment

[0067] Put the cotton thread in 10mg mL -1 Na 2 CO 3 Wash in boiling solution for 5min. Then, the cotton thread is rinsed with distilled water until the pH of the rinse solution is neutral, dried at room temperature and stored in a desiccator for future use.

Embodiment 2

[0068] Embodiment 2, effervescence-assisted liquid phase microextraction condition optimization based on convertible solvent solidification

[0069] A. Types of extractants

[0070] (1) Experimental method: Weigh 1 g of crushed sample, add 100 μL of carbaryl (10 mmol L -1 , methanol) and 1 mL of acetonitrile solution, vortex extraction for 3 min. Filter the extract with a membrane (0.22 μm), take 600 μL sample filtrate and add 4.4 mL water to a 10 mL centrifuge tube. Add 40 mg of sodium carbonate to adjust the pH of the solution to alkaline so that carbaryl is hydrolyzed into 1-naphthol, add 80 μL of hydrophobic extractant (caprylic acid, nonanoic acid, capric acid), and the extractant is converted into water-soluble Ionic form, dispersed in the sample solution. Then 70 mg of citric acid was added to generate an extractant in situ for extraction, and the bubbles generated by the effervescent reaction resulted in a larger surface area between the extraction solvent and the a...

Embodiment 3

[0090] Embodiment 3, partial optimization of thread microfluidic detection

[0091] a. Adjust the pH of the solution for optimization

[0092] (1) Experimental method: Cut the treated cotton thread into small pieces with a length of 1±0.1cm, and paste them on a white plastic board with double-sided adhesive tape. Prepare aqueous solutions of different pH (pH=1, pH=2, pH=3, pH=4, pH=5, pH=6, pH=7, pH=8, pH=9, pH=10, pH=11, pH=12, pH=13, pH=14, the pH is adjusted with HCl in the range of 1-6, and the pH is adjusted with NaOH in the range of 7-14). First add 5 μL of aqueous solutions of different pH to a 1 cm cotton thread, after the thread is wet, add 5 μL of 4-methoxybenzenediazotetrafluoroborate (10 mmol L -1 ), dry at room temperature, and finally add 7 μL 1-naphthol octanoic acid solution (concentration is 1mmol L -1 ), after 20 minutes of reaction, take pictures and calculate the RGB intensity (I).

[0093] (2) The experimental results are as follows Figure 9 shown. ...

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Abstract

The invention discloses a method for detecting the content of carbaryl in food by combining liquid phase micro-extraction with thread microfluid colorimetry. The method comprises the following steps of: 1) treating a cotton thread into neutral, then performing fixing and wetting, and adding a diazonium salt; 2) crushing a to-be-detected sample, performing extracting to obtain an extracted solution, and performing filtering with a filter membrane; (3) sequentially adding carbonate, an extracting agent and citric acid into the extracted solution, carrying out centrifugal treatment, and taking anupper-layer organic phase; 4) dripping the organic phase onto the cotton thread, photographing the cotton thread, and calculating RGB intensity according to a formula 1); and 5) preparing carbaryl standard solutions with different concentrations, drawing a standard curve by taking the concentrations of the carbaryl standard solutions as the abscissa and taking the RGB intensity as the ordinate according to the RGB intensity corresponding to the carbaryl standard solutions obtained in steps 3) and 4); and according to the standard curve and the RGB intensity determined in step 4), acquiring the concentration of carbaryl in the to-be-detected sample. According to the method provided by the invention, the reagents used in the method are green and environmentally friendly, the operation process is simple and rapid, the experiment result is accurate and reliable, and remote and on-site rapid detection can be achieved.

Description

technical field [0001] The invention relates to a method for detecting the content of carbaryl in food by combining liquid phase microextraction with thread microfluidic colorimetry, and belongs to the field of food safety detection. Background technique [0002] Crop pest and disease prevention is an important aspect of agricultural management. In recent years, many insecticides have been developed to control pests and greatly increase the overall yield of crops. Carbaryl is a broad-spectrum carbamate insecticide, which has high insecticidal activity and low bioaccumulation capacity, so it is widely used in grains, oils, vegetables and other crops to protect them from insect pests. However, the unreasonable use of carbaryl will lead to its residue in food, and then enter the human body through the food chain, resulting in the enrichment of carbaryl in the body, which will have a toxic effect on the human body. Studies have shown that carbaryl can significantly inhibit the...

Claims

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Application Information

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IPC IPC(8): G01N21/78G01N21/84
CPCG01N21/78G01N21/8483
Inventor 荆旭王慧慧王晓闻王愈冯翠萍朱俊玲陈振家
Owner SHANXI AGRI UNIV
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