CN104133023B - A kind of utilization closes the analytical approach that phase chromatogram detects tralomethrin and decis in tobacco simultaneously - Google Patents

Abstract

An analytical method for simultaneously detecting deltamethrin and deltamethrin in tobacco by use of convergence chromatography is characterized in that: firstly, acetonitrile is used to extract the residual deltamethrin and deltamethrin in the tobacco matrix, and a certain amount of Shake a certain amount of magnesium sulfate, sodium chloride, dehydrated sodium citrate, and sodium bicitrate, absorb a certain amount of supernatant after centrifugation, and carry out nitrogen blowing and concentration. After reaching a certain concentration, carry out solid phase extraction to purify it , dried with nitrogen gas, redissolved with acetonitrile solvent, passed through a 0.22 μm organic phase filter membrane, and analyzed the concentration of deltamethrin and deltamethrin in it by ultra-high performance convergence chromatography. This method is the first to use UPC ² to establish a simultaneous rapid determination method for the simultaneous detection of deltamethrin and deltamethrin in tobacco. This technology uses CO ₂ as the main mobile phase, and can realize the separation and quantitative analysis of the two compounds within 8 minutes, which can provide a basis for the relevant inspection of this index.

Description

An analytical method for the simultaneous detection of deltamethrin and deltamethrin in tobacco using convergence chromatography

Technical field:

The invention relates to the technical field of pesticide residue detection, in particular to a quantitative analysis method for simultaneous detection of deltamethrin and deltamethrin residues in tobacco by using convergence chromatography.

Background technique:

Deltamethrin is a highly active insect-resistant pesticide obtained by addition reaction of deltamethrin and bromine, which contains two isomers. The pesticide has a very significant effect on preventing and controlling the frequent pests in tobacco such as Coleoptera, Diptera and Hemiptera, so it is widely used in tobacco planting. Deltamethrin itself is also an insecticide, which has a good control effect on Lepidoptera larvae, and is often used to protect tobacco crops during planting. Permelthrin and deltamethrin are not only harmful to fish, shrimp and other aquatic organisms and beneficial insects, but the residues in tobacco will also increase the risk of health hazards to smokers and the surrounding population. Therefore, it is of great significance to monitor these two kinds of pesticide residues in tobacco.

Deltamethrin and deltamethrin have great similarity in structure, and it is difficult to detect them at the same time. At present, the detection methods of perbromethrin reported at home and abroad are mainly gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Among them, gas chromatography is the most widely used. However, due to the high temperature of about 280°C at the gas chromatograph inlet, deltamethrin decomposes to form deltamethrin, and what is actually measured by gas chromatography can only be the transformation of deltamethrin into deltamethrin. The total amount of deltamethrin, as well as deltamethrin itself, cannot be quantified separately for these two pesticide residues. The operating temperature of the convergence chromatography is generally controlled at about 50 °C. At this temperature, the properties of deltamethrin are stable, and no phenomenon of conversion into deltamethrin has been found. Therefore, the use of convergence chromatography to simultaneously detect deltamethrin in tobacco Esters and deltamethrin have certain practical application value, and can better understand the pesticide residues in tobacco.

Invention content:

The purpose of the present invention is just based on the above-mentioned state of the art and provides a kind of analytical method utilizing convergence chromatography to detect deltamethrin and deltamethrin in tobacco simultaneously, is to complete the tetramethrin in tobacco with emerging convergence chromatography technology. The simultaneous rapid analysis of deltamethrin and deltamethrin mainly uses QuRChERS pretreatment technology and solid phase extraction technology for pretreatment, and then uses ultra-high performance convergence chromatography to simultaneously analyze tetramethrin and deltamethrin. detected and quantified by the external standard method. The method has rapid instrumental analysis and uses very little organic solvent, and is an analytical method integrating multiple advantages such as high efficiency, sensitivity, and greenness.

The purpose of the present invention is achieved through the following technical solutions:

An analytical method for simultaneous detection of deltamethrin and deltamethrin in tobacco by means of convergence chromatography, firstly using acetonitrile to extract the residual deltamethrin and deltamethrin in tobacco matrix, adding a certain amount of magnesium sulfate , sodium chloride, dehydrated sodium citrate, and sodium hydrogen citrate were shaken, and after centrifugation, a certain amount of supernatant was absorbed and concentrated by nitrogen blowing. After reaching a certain concentration, it was purified by solid phase extraction. After drying with nitrogen Use acetonitrile solvent to redissolve, and after passing through a 0.22 μm organic phase filter membrane, use ultra-high performance convergence chromatography to analyze the concentration of deltamethrin and deltamethrin in it. The specific steps are as follows:

1) Extraction of samples

In order to obtain a good extraction effect, first weigh 2.0 g of pulverized tobacco samples into a 50 mL centrifuge tube with stopper, add 10 mL of ultrapure water to infiltrate the sample, let it stand for 10 min, take 10 mL of acetonitrile into the centrifuge tube, and Oscillate on a vortex mixer at a speed of 2000 rpm for 1 min, and put the centrifuge tube into a -20°C refrigerator for 10 min to prevent the decomposition of certain target substances caused by the heat generated during the salting-out process. Then add the salting-out reagent package (containing 4 g anhydrous magnesium sulfate, 1 g sodium chloride, 1 g sodium citrate and 0.5 g disodium hydrogen citrate) to the centrifuge tube, and immediately vibrate at 2000 rpm on the vortex mixer 2 min, centrifuge at 5000 rpm for 3 min, take 5 mL of the supernatant and blow with nitrogen to concentrate to 1 mL;

2) Solid phase extraction purification of samples

Using the Florisil column as the solid phase extraction column, the mixture of n-hexane and acetone (95:5, v/v) as the eluent, the concentrated sample is purified by solid phase extraction, and the specific operation steps Divided into: first, use 6 mL eluent to activate the Florisil column; secondly, inject 1 mL of the concentrated solution obtained in the previous step onto the Florisil column; third step, use Wash the column with 5 ml of eluent, and collect all the washing solution; in the fourth step, inject 3 mL of air to drain the residual liquid on the column; this step can effectively reduce matrix interference in tobacco samples.

3) Concentration, reconstitution and filtration

In order to ensure the smooth progress of the ultra-high performance convergence chromatograph analysis and achieve accurate quantification, the solvent of the extract should be replaced with 1 mL of acetonitrile. Then add 1 mL of acetonitrile to redissolve, and use a 0.22 μm organic phase filter to filter the sample as the sample solution to be tested;

4) Preparation of standard working solution

The specific method of standard working solution preparation is as follows:

Deltamethrin and deltamethrin single-label stock solution: Accurately weigh 10.0 mg (accurate to 0.1 mg) of the standard product, place it in a 10 mL volumetric flask, dissolve it with acetonitrile to make up a concentration of 1000.0 μg/ mL of single standard stock solution, stored in -20°C refrigerator for future use;

Mixed standard working solution: take 0.5ml of deltamethrin and deltamethrin single standard stock solution in a 100 mL volumetric flask, dilute with acetonitrile to make up the mass concentration of the two pesticide components to be 5.0 μg/mL respectively The mixed working stock solution was stored in a 4°C refrigerator for later use;

Preparation of series of standard solutions: Accurately pipette 0.2 mL, 0.5 mL, 1 mL, 2 mL, 5 mL of mixed standard working solutions, place them in a 10 mL volumetric flask, and dilute with acetonitrile to obtain a series of standard working solutions. For: 0.1 μg/mL, 0.25 μg/mL, 0.5 μg/mL, 1.0 μg/mL, 2.5 μg/mL, 5.0 μg/mL.

5) Convergence chromatography analysis

Concentration analysis of the standard working solution and the sample solution to be tested is carried out by an ultra-high performance convergence chromatograph, detected by an ultraviolet detector, and quantified by an external standard method;

Chromatographic conditions: the chromatographic column used is Acquity UPC ² CSH Fluoro-Phenyl chromatographic column; the pressure of ABPR is 1800 psi; the temperature of chromatographic column is 40 ℃; the injection volume is 5-10 μL; the mobile phase is CO ₂ (mobile phase A) and methanol (mobile phase B), the flow rate is 1.5 mL/min, the mobile phase gradient elution program is shown in Table 1; the UV detection wavelength is 215 nm;

Table 1 Gradient elution program

6) Method evaluation

Under the above-mentioned convergence chromatographic conditions, this method is evaluated, and the linear equation, linear range, correlation coefficient, average recovery rate, limit of quantification, etc. of the components of perdelmethrin and deltamethrin are shown in Table 2:

This method is the first to use UPC ² to establish a simultaneous rapid determination method for the simultaneous detection of deltamethrin and deltamethrin in tobacco. Based on supercritical _CO2 , combined with a small amount of acetonitrile as the mobile phase, the efficiency of chromatographic analysis is improved, and the use of organic solvents is greatly reduced, which reduces environmental pollution and reduces health threats to operators during the analysis process . The simultaneous quantitative analysis of deltamethrin and deltamethrin can be realized within 8 minutes, which fills in the deficiency that the commonly used gas chromatography method cannot quantitatively analyze these two target substances at the same time. This method can provide a basis for the relevant inspection of the above two target objects.

Description of drawings:

Figure 1: Flowchart of sample pretreatment and convergence chromatography detection.

Figure 2: Convergence chromatogram. Among them, 1 is deltamethrin; 2 and 3 are two isomers of deltamethrin (in order to highlight that deltamethrin did not undergo conversion reaction to generate deltamethrin during sample injection, the two types of target compounds were not released on the same chromatogram).

Detailed ways:

The present invention is further described in conjunction with examples, but the present invention is not limited.

Example 1:

1. Instruments and reagents:

Deltamethrin and deltamethrin: both are standard products; acetonitrile, acetone, and n-hexane are all chromatographic grade reagents.

American Waters convergence chromatograph (UPC ² ), Swiss Mettler AE 163 electronic balance (sensitivity: 0.0001g); American Labnet VtexMixer VX200 oscillator; German Sigma high-speed refrigerated centrifuge.

2. Sample handling:

For the analysis of a certain Burley tobacco sample, the sample was first extracted: 2.0 g of pulverized tobacco samples were weighed into 50 mL centrifuge tubes with stoppers, 10 mL of water was added to infiltrate the samples, and the samples were left to stand for 10 min. Take 10 mL of acetonitrile into a centrifuge tube, oscillate on a vortex mixer at 2000 rpm for 1 min, and put the centrifuge tube into a -20 °C refrigerator for 10 min. Then add the salting-out reagent package (containing 4 g anhydrous magnesium sulfate, 1 g sodium chloride, 1 g sodium citrate and 0.5 g disodium hydrogen citrate) to the centrifuge tube, and immediately vibrate at 2000 rpm on the vortex mixer 2 min, centrifuged at 5000 rpm for 3 min. Concentrate 5 mL of the supernatant to 1 mL by blowing nitrogen.

Secondly, the concentrated sample was purified by solid-phase extraction, and the specific operation steps were divided into: first, the Florisil column was activated with 6 mL of n-hexane and ethyl acetate mixture (95:5) ; Secondly, inject 1 mL of the concentrated solution obtained in the previous step onto the florisil column; in the third step, use 5 ml of a mixture of n-hexane and acetone with a volume ratio of 95:5 to wash the column , to collect all the washing solution; in the fourth step, inject 3 mL of air to drain the remaining liquid on the small column. The treatment solution was concentrated, redissolved, and the sample was filtered through a 0.22 μm organic phase filter membrane.

3. Standard solvent configuration:

The concentrations of prepared standard solutions of deltamethrin and deltamethrin series are: 0.1 μg/mL, 0.25 μg/mL, 0.5 μg/mL, 1.0 μg/mL, 2.5 μg/mL, 5.0 μg/mL.

4. Determination:

Convergence chromatography was used to analyze the standard working solution and the sample solution to be tested respectively, the ultraviolet detector was used for detection, and the external standard method was used for quantification.

Chromatographic conditions: the chromatographic column used is Acquity UPC ² CSH Fluoro-Phenyl chromatographic column; the pressure of _ABPR is 1800 psi; the temperature of chromatographic column is 60 ℃; the injection volume is 5-10 μL; Methanol (mobile phase B), the flow rate is 1.5 mL/min, the mobile phase gradient elution program is shown in Table 1; the UV detection wavelength is 215 nm. The analysis results are shown in Table 3.

Analysis results:

Table 3 Test results of actual samples (unit: mg/kg)

deltamethrin Permelthrin 0.56 0.43

Example 2:

As described in Example 1, another tobacco sample B (cured tobacco sample) was selected, and the measured contents of the two pesticide targets in the sample are shown in Table 4.

Table 4 Test results of actual samples (unit: mg/kg)

deltamethrin Permelthrin 0.61 —

Note: "—" means not detected

Example 3: Select sample C (a finished cigarette), disassemble the cigarette, collect the shredded tobacco, and pulverize it. Other operations are as described in Example 1. The contents of the two types of pesticide targets in the sample are shown in Table 5.

Table 5 Test results of actual samples (unit: mg/kg)

deltamethrin Permelthrin — —

Note: "—" means not detected.

Claims (2)

1. the analytical approach utilizing conjunction phase chromatogram simultaneously to detect tralomethrin and decis in tobacco, it is characterized in that: first utilize acetonitrile to extract tralomethrin residual in tobacco matrix and decis, add a certain amount of magnesium sulfate, sodium chloride, Sodium citrate dehydrate, natrium hydrocitricum vibrates, a certain amount of supernatant of centrifugal rear absorption carries out nitrogen and blows concentrated, after reaching finite concentration, carry out Solid-Phase Extraction and purified treatment is carried out to it, acetonitrile solvent is utilized to redissolve after nitrogen dries up, after crossing 0.22 μm of organic phase filter membrane, utilize ultra high efficiency to close chromatography and concentration analysis is carried out to tralomethrin wherein and decis, concrete steps are as follows:

1) extraction of sample

First tobacco sample that 2.0 g have pulverized is taken in 50 mL tool plug centrifuge tubes, add 10 mL ultrapure waters and infiltrate sample, leave standstill 10 min, get 10 mL acetonitriles in centrifuge tube, with 2000 rpm velocity fluctuation 1 min on vortex mixer, centrifuge tube is put into-20 ° of C refrigerator freezing 10 min, then add in centrifuge tube containing 4 g anhydrous magnesium sulfates, 1 g sodium chloride, the pack of saltouing of 1 g sodium citrate and 0.5 g natrium hydrocitricum, to vibrate 2 min with 2000 rpm on vortex mixer immediately, with centrifugal 3 min of 5000 rpm, get 5mL supernatant liquid nitrogen to blow and be concentrated into 1mL,

2) Solid phase extraction of sample

Adopt florisil silica pillar as solid-phase extraction column, be that the mixed liquor of the normal hexane of 95:5 and acetone is as eluent with v/v, carry out Solid phase extraction process to the sample concentrated, concrete operation step is divided into: first, utilizes 6 mL eluents to carry out activation process to florisil silica pillar; Secondly, 1mL concentrate previous step obtained is injected on florisil silica pillar; 3rd step, utilizes 5 ml eluents to wash pillar, collects whole cleansing solution; 4th step, injects 3 mL air with liquid residual on emptying pillar;

3) concentrate, redissolve and filter

First concentrated near dry to the eluent collected with Nitrogen evaporator, then add 1 mL acetonitrile and redissolve, and utilize 0.22 μm of organic phase filter membrane to filter sample, as sample liquid to be measured;

4) standard working solution preparation

The series standard solution concentration of tralomethrin and decis is: 0.1 μ g/mL, 0.25 μ g/mL, 0.5 μ g/mL, 1.0 μ g/mL, 2.5 μ g/mL, 5.0 μ g/mL;

5) analysis of hplc is closed

Adopt ultra high efficiency to close chromatography and carry out concentration analysis to standard working solution and sample liquid to be measured, UV-detector detects, quantified by external standard method;

Chromatographic condition: adopt chromatographic column to be Acquity UPC ²cSH Fluoro-Phenyl chromatographic column; ABPR pressure is 1800 psi; Chromatogram column temperature is 40 DEG C; Sample size is 5-10 μ L; Mobile phase is respectively mobile phase A: CO ₂and Mobile phase B: methyl alcohol, flow velocity is 1.5 mL/min, and eluent gradient elution program is as table 1; UV detect wavelength is 215 nm;

Table 1 gradient elution program

。

2. according to claim 1 utilization closes the analytical approach that phase chromatogram detects tralomethrin and decis in tobacco simultaneously, it is characterized in that: the concrete grammar of standard working solution preparation is as follows:

Tralomethrin and decis list mark storing solution: accurately take the standard items that 10.0 mg are accurate to 0.1 mg, be placed in 10 mL volumetric flasks, dissolve constant volume with acetonitrile, be mixed with the list mark storing solution that mass concentration is 1000.0 μ g/mL, be stored in-20 ° of C refrigerators for subsequent use;

Hybrid standard working solution: get tralomethrin and decis list mark storing solution 0.5ml respectively in 100 mL volumetric flasks, use dilution in acetonitrile constant volume, be mixed with the hybrid working storing solution that two kinds of pesticide composition mass concentrations are respectively 5.0 μ g/mL, be stored in 4 ° of C refrigerators for subsequent use;

Series standard solution preparation: the hybrid standard working solution accurately pipetting 0.2 mL, 0.5 mL, 1 mL, 2 mL, 5 mL, be placed in 10 mL volumetric flasks, use acetonitrile constant volume, obtain series standard working solution, concrete concentration is: 0.1 μ g/mL, 0.25 μ g/mL, 0.5 μ g/mL, 1.0 μ g/mL, 2.5 μ g/mL, 5.0 μ g/mL.