WO2017121061A1

WO2017121061A1 - Rapid detection method for residual trithion in fruits and vegetables

Info

Publication number: WO2017121061A1
Application number: PCT/CN2016/083706
Authority: WO
Inventors: 康怀志; 刘国坤; 曾勇明; 陈启振
Original assignee: 厦门大学
Priority date: 2016-01-12
Filing date: 2016-05-27
Publication date: 2017-07-20
Also published as: CN105572098A

Abstract

Provided is a rapid detection method for residual trithion in fruits and vegetables. A fruit and vegetable sample is placed into a container, an extracting agent and a water storing agent are added, and ultrasonic extraction is performed so as to obtain an extracting solution. The extracting solution is placed into a container with a cover; anhydrous magnesium sulphate, graphitized carbon and bonded silica gel PSA are added, and standing is performed after oscillation is performed. A supernate is placed into another container with a cover, a low-polarity organic solvent is added, and standing is performed for the second time after oscillation is performed for the second time. 0.5-4 ml is taken therefrom and placed into a test tube, blow-drying with nitrogen is performed, an eluent is then added, and oscillation is performed for the third time. The eluent is taken therefrom and placed into a detection cell, a metal sol and an inorganic salt flocculating agent are then added and mixed until uniform, and detection is performed inside a detection room of a Raman spectrometer. The operation is easy and convenient, and the detection can be achieved without professionals. The detection time is short, and the rapid screening of large quantities of samples can be achieved. The accuracy is high, and no false positive phenomenon occurs. Large amounts of an organic solvent and a toxic reagent are not required, and thus no harm is caused to the physical health of detection personnel and the environment.

Description

Rapid detection method of trisulfide residue in fruits and vegetables

Technical field

The invention relates to the detection of pesticide residues in fruits and vegetables, in particular to a rapid detection method of trisulfide residues in fruits and vegetables.

Background technique

There are many kinds of organophosphorus pesticides, which are highly toxic, mainly entering the human body through skin contact, breathing and direct consumption. At present, there are hundreds of organophosphorus pesticides registered in the world, which are widely used in China. There are dozens of organophosphorus pesticides. The structural formula of organophosphorus pesticides is X=PZ(R1)(R2), where X represents =O or =S, Z represents a halogen group, an alkoxy group or other substituents, etc., R1, R2 Represents methoxy (CH3O-) or ethoxy (C2H5O-). The molecular structure of organophosphorus pesticides is divided into two categories: one is P = O, such as dichlorvos, omethoate, etc.; the other is P = S, such as phorate, methyl pyrimidine and the like. Organophosphorus pesticides contain P=O, P=S, C-P, C-O-P, C-N-P, and C-S-P bonds. Except for trichlorfon and dimethoate, most of them are insoluble in water, soluble in organic solvents, and easily hydrolyzed under alkaline conditions. Organophosphorus pesticides can enter the human body through breathing, contact, etc. It circulates through the blood and lymph to various organs and tissues throughout the body. When organophosphorus pesticides enter the nervous system and combine with the acetylcholinesterase active center to form phosphorylcholinesterase, phosphorylated cholinesterase is more difficult to hydrolyze, destroying the activity of cholinesterase. It causes acetylcholine to accumulate on the synapses, interferes with the normal conduction of nerve impulses, and finally leads to the death of the animal. Organophosphorus pesticides have the advantages of broad spectrum, high efficiency, easy degradation, and low price. It is the preferred pesticide variety for controlling a variety of pests in China. However, due to the extensive use of organophosphorus pesticides, organophosphorus pesticide residues exist on the surface of crops and fruits and vegetables, posing a serious threat to the lives and lives of the people. Therefore, long-term consumption of foods that utilize SO2 bleaching is extremely harmful to the human body. Thus, in the national standard GB 2763-2014 "National Standards for Food Safety Standards for Maximum Residues of Pesticides in Foods" does not regulate trisulfide, that is, trisulfide cannot be left in food.

At present, the main standard for the detection of organophosphorus residues in fruits and vegetables in China is NYT. 761-2008 "Determination of organophosphorus, organochlorine, pyrethroid and carbamate pesticide residues in vegetables and fruits", GBT 19648-2006 "Determination of Residues of 500 Pesticides and Related Chemicals in Fruits and Vegetables by Gas Chromatography-Mass Spectrometry", SNT0148-2011 "Methods for Determination of Organophosphorus Pesticide Residues in Import and Export of Fruits and Vegetables Gas chromatography and gas chromatography-mass spectrometry and GBT 5009.218-2008 "Determination of a variety of pesticide residues in fruits and vegetables", these standards are extracted by homogenization with organic solvents, combined with liquid-liquid extraction or solid-phase extraction for impurity removal, and finally detected by chromatography. These standard solutions require complex pre-treatment of the sample, which takes a long time to measure and requires professional technicians to complete it in the laboratory.

In addition, QuEChERS and chromatographic combined detection of organic phosphorus is widely used in the laboratory, which is extracted by acetic acid acidified acetonitrile and purified by dispersive solid phase extraction. Compared with the existing domestic standards, although the pre-processing process is simplified and no professional technicians are needed, it still uses chromatographic detection. The terminal test still requires professionals and cannot leave the laboratory.

At present, there is also a rapid detection card for organophosphorus pesticides on the market, which is made of cholinesterase and chromogenic reagent which are highly sensitive to organic phosphorus. Although this method is easy to operate, it is prone to false positives and can only be used. Determination of organophosphorus, which is highly sensitive to cholinesterase, does not identify which organophosphorus is specifically.

Summary of the invention

The object of the present invention is to provide a rapid detection method for trisulfide residues in fruits and vegetables.

The invention comprises the following steps:

1) Put the fruit and vegetable sample into the container, add the extracting agent, the water storage agent, and ultrasonically extract to obtain the extract; In the step 1), the fruit and vegetable sample may adopt 2g; the fruit and vegetable include vegetables, cabbage, pear, apple, orange, etc.; the ratio of the extracting agent to the water storage agent may be 5-10 ml: 0.5-2 g , preferably 8 ml: 1 g, wherein the extracting agent is calculated by volume, the water storage agent is calculated by mass; the extracting agent may be acetonitrile or acetonitrile and acetic acid, and the acetic acid may be 0.1% to 1% by volume of acetonitrile; The water storage agent may be selected from one of anhydrous magnesium sulfate, anhydrous sodium sulfate, and the like; the ultrasonic extraction may be carried out for 2 to 10 minutes, preferably 5 minutes.

2) The extract obtained in the step 1) is placed in a container with a lid, anhydrous magnesium sulfate, graphitized carbon and bonded silica PSA are added, shaken, left to stand, and the supernatant is placed in another container with a lid, and added. Low-polar organic solvent, after the second shaking, it is allowed to stand for the second time. Take 0.5~4ml into the test tube, blow dry with nitrogen, add the eluent, shake for the third time, and take the eluent in the detection tank. Then, the metal sol and the inorganic salt flocculant are added and mixed, and placed in a Raman spectrometer for detection.

In the step 2), the ratio of the extract, anhydrous magnesium sulfate, graphitized carbon, bonded silica PSA and low-polar organic solvent may be 3-8 ml: 0.05-0.2 g: 5-50 mg: 0.02- 0.2g: 2 to 5ml, the ratio of the extract, anhydrous magnesium sulfate, graphitized carbon, bonded silica PSA and low polar organic solvent may preferably be 5ml: 0.1g: 20mg: 0.1g: 3ml, wherein , the extract, the low-polarity organic solvent is calculated by volume, the anhydrous magnesium sulfate, the graphitized carbon and the bonded silica PSA are calculated by mass; the shaking time may be 5-30 s, preferably 20 s; the standing time It may be 0.5 to 5 min, preferably 1 min; the low polar organic solvent may be selected from one of petroleum ether, n-hexane, cyclohexane, heptane, etc.; the second oscillation may be 5 to 30 s. , preferably 10 s; the second resting time may be 0.5 to 5 min, preferably 1 min; The volume ratio of the eluent, eluent, metal sol and inorganic salt flocculant may be from 200 to 1000:200:10 to 100:10, and the eluent, eluent, metal sol and inorganic salt flocculate. The volume ratio of the agent may preferably be 400:200:10:10; the eluent may be a water-miscible organic solvent aqueous solution, and the water-miscible organic solvent may be selected from the group consisting of acetonitrile, ethanol, methanol, acetone, and One of methyl sulfoxide and the like; the mass ratio of the water-miscible organic solvent may be 10% to 30%, preferably 20%; and the time of the third oscillation may be 5 to 30 s, preferably 10 s. The metal sol may be selected from 55 nm Au, 55nm Ag, 55nm with pinhole SHINERS, 120nm Au, 120 nm has one of pinhole SHINERS, etc.; the inorganic salt flocculant may have a molar ratio of 0.01 to 5 M, preferably 0.08 M; the inorganic salt flocculating agent may be selected from the group consisting of barium chloride, potassium iodide, sodium iodide, potassium chloride, magnesium chloride, calcium chloride, aluminum chloride, potassium sulfate, sodium sulfate, magnesium sulfate, potassium phosphate, sodium phosphate, One of potassium carbonate, sodium carbonate, etc.; the Raman spectrometer can have a power of 280 mW, a laser wavelength of 785 nm, and a scanning range of 200 to 2000 nm.

Compared with the existing method for detecting trisulfide residues in fruits and vegetables, the present invention has the following outstanding advantages:

1) Easy to operate, no need to be professional to achieve detection;

2) Short detection time, rapid screening of large batch samples;

3) High accuracy and no false positives occur;

4) Extracting, purifying and enriching trisulfide with simple adsorbent and liquid-liquid extraction, using metal sol for detection, without using a lot of organic solvents and toxic reagents, for the health and environment of the test personnel They will not be harmed and friendly to the environment.

DRAWINGS

Figure 1 is a test curve of trithiophos in the cabbage of Example 1. Sample source: commercially available cabbage plus standard trisulfide sample, Raman spectrometer power 280mW, laser wavelength 785nm, integration time 5s;

2 is a trithiophos test curve in the pakchoi of Example 2. Sample source: commercially available cabbage plus standard trisulfide sample, Raman spectrometer power 280mW, laser wavelength 785nm, integration time 5s;

Figure 3 is a trithiophos test curve for the orange of Example 3. Sample source: commercially available orange peel plus trisulfide sample, Raman spectrometer power 180mW, laser wavelength 785nm, integration time 5s;

4 is a test curve of trisphosphonate in apple of Example 4. Sample source: Commercially available apple spiked trisulfide sample, Raman spectrometer power 280mW, laser wavelength 785nm, integration time 5s.

detailed description

The invention will be further illustrated by the following examples in conjunction with the accompanying drawings.

Example 1

This embodiment includes the following steps:

1) Put the cabbage sample into a container, add an extracting agent, a water storage agent, and ultrasonically extract to obtain an extract; the cabbage sample is 2 g; the ratio of the extracting agent to the water storage agent may be 5 to 10 ml. : 0.5 ~ 2g, preferably 8ml : 1g, wherein the extractant is calculated by volume, the water storage agent is calculated by mass; the extracting agent may be acetonitrile or acetonitrile and acetic acid, and the acetic acid may be 0.1% to 1% by volume of acetonitrile. The water storage agent may be selected from one of anhydrous magnesium sulfate, anhydrous sodium sulfate, and the like; the ultrasonic extraction may be carried out for 2 to 10 minutes, preferably 5 minutes. The source of the cabbage sample: the commercially available cabbage is spiked with the sample of trisulfide.

2) The extract obtained in the step 1) is placed in a container with a lid, anhydrous magnesium sulfate, graphitized carbon and bonded silica PSA are added, shaken, left to stand, and the supernatant is placed in another container with a lid, and added. Low-polar organic solvent, after the second shaking, it is allowed to stand for the second time. Take 0.5~4ml into the test tube, blow dry with nitrogen, add the eluent, shake for the third time, and take the eluent in the detection tank. Then, the metal sol and the inorganic salt flocculant are added and mixed, and placed in a Raman spectrometer for detection. The ratio of the extract, anhydrous magnesium sulfate, graphitized carbon, bonded silica PSA and low polar organic solvent may be 3-8 ml: 0.05-0.2 g: 5-50 mg: 0.02-0.2 g: 2-5 ml. The ratio of the extract, the anhydrous magnesium sulfate, the graphitized carbon, the bonded silica PSA and the low polar organic solvent may preferably be 5 ml: 0.1 g: 20 mg: 0.1 g: 3 ml, wherein the extract, the low pole The organic solvent is calculated by volume, anhydrous magnesium sulfate, graphitized carbon and bonded silica PSA are calculated by mass; the shaking time may be 5-30 s, preferably 20 s; the standing time may be 0.5-5 min, Preferably, the low polar organic solvent may be selected from one of petroleum ether, n-hexane, cyclohexane, heptane, etc.; the second oscillation may be carried out for 5 to 30 s, preferably 10 s; The second standing time may be 0.5 to 5 min, preferably 1 min; The volume ratio of the eluent, eluent, metal sol and inorganic salt flocculant may be from 200 to 1000:200:10 to 100:10, and the eluent, eluent, metal sol and inorganic salt flocculate. The volume ratio of the agent may preferably be 400:200:10:10; the eluent may be a water-miscible organic solvent aqueous solution, and the water-miscible organic solvent may be selected from the group consisting of acetonitrile, ethanol, methanol, acetone, and One of methyl sulfoxide and the like; the mass ratio of the water-miscible organic solvent may be 10% to 30%, preferably 20%; and the time of the third oscillation may be 5 to 30 s, preferably 10 s. The metal sol may be selected from 55 nm Au, 55nm Ag, 55nm with pinhole SHINERS, 120nm Au, 120 nm has one of pinhole SHINERS, etc.; the inorganic salt flocculant may have a molar ratio of 0.01 to 5 M, preferably 0.08 M; the inorganic salt flocculating agent may be selected from the group consisting of barium chloride, potassium iodide, sodium iodide, potassium chloride, magnesium chloride, calcium chloride, aluminum chloride, potassium sulfate, sodium sulfate, magnesium sulfate, potassium phosphate, sodium phosphate, One of potassium carbonate, sodium carbonate, etc.; the Raman spectrometer can have a power of 280 mW, a laser wavelength of 785 nm, and a scanning range of 200 to 2000 nm.

See Figure 1 for the trithiophos test curve in the cabbage of Example 1. The Raman spectrometer has a power of 280 mW, a laser wavelength of 785 nm, and an integration time of 5 s.

Example 2

Similar to Example 1, the difference is in the source of the fruit and vegetable sample: a commercially available Chinese cabbage spiked with a sample of trisulfide.

The trithiophos test curve of the pakchoi of Example 2 is shown in Fig. 2. The Raman spectrometer has a power of 280 mW, a laser wavelength of 785 nm, and an integration time of 5 s.

Example 3

Similar to Example 1, the difference is in the source of the fruit and vegetable sample: a commercially available orange peel plus a sample of trisulfide.

The test curve of the trithiophos in the orange of Example 3 is shown in Fig. 3. The Raman spectrometer has a power of 180 mW, a laser wavelength of 785 nm, and an integration time of 5 s.

Example 4

Similar to Example 1, the difference is in the source of the fruit and vegetable samples: a commercially available apple spiked trisulfide sample.

See Figure 4 for the trithiophos test curve for apples of Example 4. The Raman spectrometer has a power of 280 mW, a laser wavelength of 785 nm, and an integration time of 5 s.

The reinforcing agent used in the present invention comprises bare gold, silver, copper nanoparticles (having a particle size of 30 to 200 nm), and pinhole-containing SHINERS particles and pinhole-free SHINERS particles having a core particle diameter of 30 to 200 nm, and a shell The layer thickness is 1 to 10 nm.

The pretreatment method is to extract the test substance in the sample from the fruits and vegetables by using acetonitrile (which may contain 0.1% to 1% acetic acid), and remove a small amount of water contained in the sample by using anhydrous magnesium sulfate, and use the bonded silica PSA. And graphitized carbon GCB to remove the organic acid and other substrates in the extract, and extract the test substance by petroleum ether (low-polar organic solvent such as n-hexane, cyclohexane or heptane) for further purification and purification. Using surface-enhanced Raman spectroscopy as a detection technique, rapid detection of the substance to be tested can be achieved. Therefore, the previous treatment method combined with surface-enhanced Raman spectroscopy can simplify the pre-processing process and achieve rapid detection of the substance to be tested, which is suitable for large-scale samples. Quick screening

The adsorbent used includes a bonded silica PSA and a graphitized carbon GCB, wherein the bonded silica PSA is used in an amount of 0.02 to 0.2 g, preferably 0.1 g, and graphitized carbon is 5 to 50 mg, preferably 20 mg.

The above has described in detail the preferred embodiments of the invention. It should be understood that many modifications and variations can be made in the present invention without departing from the scope of the invention. Therefore, any technical solution that can be obtained by a person skilled in the art based on the prior art based on the prior art by logic analysis, reasoning or limited experimentation should be within the scope of protection determined by the claims.

Claims

A rapid detection method for trisulfide residues in fruits and vegetables, characterized in that the method comprises the following steps: 1) Put the fruit and vegetable sample into the container, add the extracting agent, the water storage agent, and ultrasonically extract to obtain the extract; 2) The extract obtained in the step 1) is placed in a container with a lid, anhydrous magnesium sulfate, graphitized carbon and bonded silica PSA are added, shaken, left to stand, and the supernatant is placed in another container with a lid, and added. Low-polar organic solvent, after the second shaking, it is allowed to stand for the second time. Take 0.5~4ml into the test tube, blow dry with nitrogen, add the eluent, shake for the third time, and take the eluent in the detection tank. Then, the metal sol and the inorganic salt flocculant are added and mixed, and placed in a Raman spectrometer for detection.
The method for rapidly detecting a trisulfide residue in a fruit or vegetable according to claim 1, wherein in the step 1), the fruit and vegetable sample is 2 g; and the fruit and vegetable comprises a vegetable, a cabbage, a pear, an apple, and an orange.
The method for rapidly detecting trisulfide residues in fruits and vegetables according to claim 1, wherein in the step 1), the ratio of the extracting agent to the water storage agent is 5 to 10 ml: 0.5 to 2 g, preferably 8 ml: 1 g, wherein the extractant is calculated by volume, and the water storage agent is calculated by mass.
The method for rapidly detecting trisulfide residues in fruits and vegetables according to claim 1, wherein in the step 1), the extracting agent is acetonitrile or acetonitrile and acetic acid, and the acetic acid is 0.1% by volume of acetonitrile. ～1%; the water storage agent may be selected from one of anhydrous magnesium sulfate and anhydrous sodium sulfate; the ultrasonic extraction may be carried out for 2 to 10 minutes, preferably 5 minutes.
A method for rapidly detecting trisulfide residues in fruits and vegetables according to claim 1, wherein in the step 2), the extract, anhydrous magnesium sulfate, graphitized carbon, bonded silica PSA and low polarity organic The solvent ratio is 3 to 8 ml: 0.05 to 0.2 g: 5 to 50 mg: 0.02 to 0.2 g: 2 to 5 ml, and the extract, anhydrous magnesium sulfate, graphitized carbon, bonded silica PSA, and low polarity organic The ratio of the solvent may preferably be 5 ml: 0.1 g: 20 mg: 0.1 g: 3 ml, wherein the extract, the low polar organic solvent is calculated by volume, and anhydrous magnesium sulfate, graphitized carbon, and bonded silica PSA are calculated by mass.
The method for rapidly detecting a trisulfide residue in a fruit or vegetable according to claim 1, wherein in the step 2), the shaking time is 5 to 30 s, preferably 20 s; and the standing time may be 0.5 ～. 5 min, preferably 1 min.
The method for rapidly detecting trisulfide residues in fruits and vegetables according to claim 1, wherein in the step 2), the low polar organic solvent is selected from the group consisting of petroleum ether, n-hexane, cyclohexane and heptane. One time; the second shaking time may be 5-30 s, preferably 10 s; the second resting time may be 0.5-5 min, preferably 1 min.
The method for rapidly detecting trisulfide residues in fruits and vegetables according to claim 1, wherein in step 2), the volume ratio of the eluent, the eluent, the metal sol and the inorganic salt flocculant is 200 ～ The volume ratio of the eluent, the eluent, the metal sol and the inorganic salt flocculant may preferably be 400:200:10:10 in the range of 1000:200:10 to 100:10.
The method for rapidly detecting a trisulfide residue in a fruit or vegetable according to claim 1, wherein in the step 2), the eluent is a water-miscible organic solvent aqueous solution, and the water-miscible organic solvent is One selected from the group consisting of acetonitrile, ethanol, methanol, acetone, and dimethyl sulfoxide; the water-miscible organic solvent may have a mass concentration of 10% to 30%, preferably 20%; the third oscillation The time may be 5 to 30 s, preferably 10 s.
The method for rapidly detecting trisulfide residues in fruits and vegetables according to claim 1, wherein in step 2), the metal sol is selected from the group consisting of 55 nm Au and 55 nm. Ag, 55nm pinhole SHINERS, 120nm Au, 120nm pinhole SHINERS; the inorganic salt flocculant molar ratio may be 0.01-5M, preferably 0.08 M; the inorganic salt flocculating agent may be selected from the group consisting of barium chloride, potassium iodide, sodium iodide, potassium chloride, magnesium chloride, calcium chloride, aluminum chloride, potassium sulfate, sodium sulfate, magnesium sulfate, potassium phosphate, sodium phosphate, One of potassium carbonate and sodium carbonate; the Raman spectrometer can have a power of 280 mW, a laser wavelength of 785 nm, and a scanning range of 200 to 2000 nm.