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Fast detection method for residual dicofol in tea leaves

A technology for dicofol and a detection method, applied in the fields of analytical chemistry and food safety, can solve the problems of low recovery rate of dicofol, large consumption of reagents, complicated pretreatment, etc., and achieve the effects of low cost, simple operation and high sensitivity

Inactive Publication Date: 2015-04-29
INSPECTION & QUARANTINE TECH CENT OF FUJIAN ENTRY EXIT INSPECTION & QUARANTINE BUREAU
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

These methods have high sensitivity, but require the use of large analytical instruments, expensive equipment, complicated pretreatment, and large consumption of reagents
In addition, gas chromatography also has the problem of low recovery rate due to thermal decomposition of dicofol
At present, there is no method at home and abroad that can quickly and easily test the residual amount of dicofol in tea leaves. Therefore, in the face of tea safety issues that are widely concerned by the whole society, it is necessary to develop a fast, simple, low-cost test method that can be applied in general places. Methods and techniques are positive

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0011] 1. Reagents

[0012] Pyridine: analytically pure, redistilled

[0013] Acetone: analytically pure

[0014] n-Hexane: analytically pure

[0015] Concentrated sulfuric acid: analytically pure, content 98%

[0016] Sodium hydroxide: analytically pure

[0017] Sodium hydroxide solution: 50% aqueous solution

[0018] Dicofol standard solution: Use n-hexane to make a standard stock solution with a concentration of 1.00 mg / mL, and dilute it into a working solution with an appropriate concentration as required.

[0019] 2. Operation steps

[0020] Extract - Purify : Weigh 1.00g sample into a centrifuge tube, add 1.0mL water, 1.0mL acetone, mix for 30s; add 2.0mL n-hexane, mix for 1min, absorb the upper layer (n-hexane) into the purification column; then centrifuge Add 2 mL of n-hexane to the tube, mix for 1 min, and absorb the upper layer (n-hexane) into the purification column. Receive the first 2mL of effluent after column purification in a centrifuge tube.

[0021] ...

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Abstract

The invention discloses a fast detection method for residual dicofol in tea leaves. The fast detection method is characterized in that one-step purification of tea-leaf extracting solution is realized by a high-efficiency sulfonation small column; the purified extracting solution is concentrated, the dicofol is degraded to generate trichloromethane under certain condition and forms a red compound with pyridine, then comparison with standard colorimetric solution or a colorimetric card is made to judge that whether the dicofol exists or not and whether the content of the dicofol exceeds the standard or not. The fast detection method disclosed by the invention has the advantages of simplicity in operation, short consumed time, high sensitivity and low cost, and the detection limit can reach 0.5mg / kg.

Description

technical field [0001] The invention belongs to the technical fields of analytical chemistry and food safety, and in particular relates to a rapid detection method for dicofol residues in tea leaves. Background technique [0002] Dicofol residues are a very prominent problem of tea pesticide residues in recent years. The only crops that allow the use of dicofol in my country are cotton and apples, but tea farmers in some places have expanded the use of dicofol to tea trees at will, making dicofol residues in tea a prominent problem. For this reason, the Ministry of Agriculture issued the "Notice on Prohibiting the Use of Dicofol on Tea Trees" in 1997. Among the exported tea, dicofol ranks first in the residue exceeding the standard in my country for many years. In addition, due to technological reasons, dicofol pesticides in my country contain 3% to 10% DDT, and the use of dicofol has become a new factor for DDT residues. Therefore, the residue of dicofol in tea is a prob...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78G01N21/25
Inventor 蔡春平丁立平王丹红潘迎芬许仁杰
Owner INSPECTION & QUARANTINE TECH CENT OF FUJIAN ENTRY EXIT INSPECTION & QUARANTINE BUREAU
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