Enzyme inhibition method for detecting carbamates

A technology of carbamates and dithiodinitrobenzoic acid, applied in the field of chemistry, can solve problems such as no mention of urethane, limited, etc., and achieve the effect of simple steps, simple and fast methods, and less equipment

Inactive Publication Date: 2013-09-25
GUANGZHOU INST FOR FOOD INSPECTION(GUANGZHOU INSPECTION CENT FOR WINE & SPIRITS) +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in these documents, the detected carbamates are very limited. For example, GBT 18630-2002 and GBT 5009-2003 mentioned that carbaryl (1.0 mg/kg), carbaryl (1.0 mg/kg), and

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] (1) Add 5mL EC standard solution (20g / L, excess) (0.1mol / L, pH9.0 phosphate buffer solution) into the test tube;

[0048] (2) Add 50-200ul acetylcholinesterase (13mg / mL) and 50-200ul DTNB (10mg / mL), and react in a water bath at 30-40°C for 10-30min;

[0049] (3) Add 50-200ul of thioacetylcholine iodide (10mg / mL), mix well and immediately use a 1cm cuvette at a wavelength of 412nm for colorimetry, and use a buffer without EC as a control. Record the change value of absorbance with time for 3 minutes △A 0 and △A 1 . A 0 =0.3830, △A 1 =0.3910, excess EC has no inhibitory effect on acetylcholinesterase.

Embodiment 2

[0051] (1) Add 5mL EC standard solution (20g / L, excess) (prepared in 0.1mol / L, pH9.0 phosphate buffer) to the test tube, then add 20-200ul bromine preparation (bromine water-sodium hydroxide solution) Oxidize for 10-20 minutes, and reduce with 60-600ul 5-15% sodium nitrite; in the bromine water-sodium hydroxide solution used, the mass fraction of bromine is 3%, and the concentration of sodium hydroxide is 0.001mol / L.

[0052] (2) Add 50-200ul acetylcholinesterase (13mg / mL) and 50-200ul DTNB (10mg / mL), and react in a water bath at 30-40°C for 10-30min;

[0053] (3) Add 50-200ul of thioacetylcholine iodide (10mg / mL), mix well and immediately use a 1cm cuvette at a wavelength of 412nm for colorimetry, and use a buffer without EC as a control. Record the change value of absorbance with time for 3 minutes A 0 and △A 1 . A 0 =0.3830, △A 1 =-0.0063, the inhibition rate of excess EC oxidized by bromine preparations was significantly increased, reaching 101.64%.

Embodiment 3

[0055] (1) Add 5ml of EC standard solution (2mg / L) into the test tube, then add 20-200ul oxidant (bromine preparation) to oxidize for 10-20min, and reduce with 60-600ul 5-15% sodium nitrite; the bromine preparation is bromine water -sodium hydroxide solution; in the bromine water-sodium hydroxide solution adopted, the mass fraction of bromine is 5%, and the concentration of sodium hydroxide is 0.002mol / L.

[0056] (2) Add 50-200ul acetylcholinesterase (13mg / mL) and 50-200ul DTNB (10mg / mL), and react in a water bath at 30-40°C for 10-30min;

[0057] (3) Add 50-200ul of thioacetylcholine iodide (10mg / mL), mix well and immediately use a 1cm cuvette at a wavelength of 412nm for colorimetry, and use a buffer without EC as a control. Record the change value of absorbance with time for 3 minutes A 0 and △A 1 . A 0 =0.3830, △A 1 =0.23635, 2mg / L EC standard solution oxidized by oxidant, the inhibition rate can reach 38.29%

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PUM

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Abstract

The invention relates to the chemical field and in particular to an enzyme inhibition method for detecting carbamates. Ethyl carbamate is oxidized by using an oxidant in the presence of an acetylcholine iodide substrate, a 5,5'-dithio bis-(2-nitrobenzoic acid) (DTNB) developer and an acetylcholin esterase with the activity of more than 200U/g, and then the absorbance variation value of the ethyl carbamate along with time at 3min is detected by spectrophotometry to obtain the inhibition condition of the ethyl carbamate on the acetylcholin esterase so as to obtain the content of the ethyl carbamate. The substrate and the developer used in the invention are low in cost; the inhibition rate is greatly increased since the ethyl carbamate is oxidized by using the oxidant; and the method is rapid, simple, high in sensitivity, mild and easily controlled in reaction conditions, simple in steps and easy to operate and needs less equipment. According to the principle of the method, a rapid kit is developed for the rapid detection of ethyl carbamates in alcoholic beverages and fermented foods.

Description

technical field [0001] The invention relates to the field of chemistry, in particular to an enzyme inhibition method for detecting carbamates. Background technique [0002] Ethyl Carbamate (EC for short) is a pollutant naturally produced in fermented wine during fermentation and storage. EC was confirmed as a carcinogen as early as 1943. Studies have shown that in rodents, EC is a multi-site carcinogen, which can cause diseases such as lung cancer, lymphoma, liver cancer and skin cancer. In 2007, the International Cancer Research Institute classified EC's carcinogenic toxicity to humans as category 2A. At present, the pollution of ethyl carbamate is considered to be another important problem after aflatoxin in food. [0003] Enzyme inhibition method is the most researched and relatively mature technology for rapid detection of organophosphorus and ethyl carbamate pesticides. The method for the detection of organophosphorus and urethane pesticides has the advantages of ra...

Claims

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Application Information

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IPC IPC(8): G01N21/31
Inventor 黄秋婷刘丽斌彭程黄惠华邱佩丽
Owner GUANGZHOU INST FOR FOOD INSPECTION(GUANGZHOU INSPECTION CENT FOR WINE & SPIRITS)
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