CN112697916A - Method for detecting triazine pesticide in soil - Google Patents

Abstract

The invention relates to a method for detecting triazine pesticides in soil. The detection method comprises the following steps: preparation of sample solution to be tested: taking a soil sample, carrying out pressurized solvent extraction by using an extraction solvent, purifying and concentrating the obtained extracting solution, and adding an internal standard of quintozene to be used as a sample solution to be detected; performing gas chromatography determination and mass spectrometry determination on the sample solution to be detected; wherein the extraction solvent is n-hexane-acetone mixed solution or acetonitrile; the triazine pesticide is at least one of ametryn, atrazine, prometon, prometryn, simazine, simetryn, terbuthylazine and terbutryn. The detection method has the advantages of good chromatographic peak pattern, high separation degree, high sensitivity, low detection limit and simple and convenient operation.

Description

Method for detecting triazine pesticide in soil

Technical Field

The invention relates to the field of analysis, in particular to a method for detecting triazine pesticides in soil.

Background

Triazine pesticides are one of the traditional herbicides that were introduced as early as the 50 s in the 20 th century. Such herbicides have been used to a great extent in agriculture, but the market for their use is decreasing due to their large use levels, long residues and high carcinogenic toxicity. Triazine pesticides have low water solubility, can form independent non-aqueous phase, are easy to adsorb in solid environment media such as soil and the like, and are left for a long time. The european union stopped the use of triazine pesticides in agriculture at the end of 2007. China promulgates' soil pollution risk control standards (trial) for soil environment quality construction land in 2018, GB36600-2018, strictly controls the content of atrazine in the soil of the construction land, wherein the risk screening value of the first-class land is 2.6 mg/kg. It can be seen that the detection of triazine pesticides is crucial in assessing soil environmental quality. At present, the triazine pesticides in soil are mainly extracted by a Soxhlet extraction method, an ultrasonic extraction method, a pressurized solvent extraction method (ASE) and the like, and instrument detection methods comprise a high performance liquid chromatography, a gas chromatography-mass spectrometry and the like. However, the accuracy and sensitivity of the current detection method are still not ideal, and the defects that the peaks cannot be well separated exist.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a method for detecting a triazine-based pesticide in soil, which has high sensitivity and high accuracy and can realize excellent separation of each spectrum peak.

The specific technical scheme is as follows:

a method for detecting triazine pesticides in soil comprises the following steps:

preparation of sample solution to be tested: taking a soil sample, carrying out pressurized solvent extraction by using an extraction solvent, purifying and concentrating the obtained extracting solution, and adding an internal standard of quintozene to be used as a sample solution to be detected;

performing gas chromatography determination and mass spectrometry determination on the sample solution to be detected;

wherein the extraction solvent is n-hexane-acetone mixed solution or acetonitrile;

the triazine pesticide is at least one of ametryn, atrazine, prometon, prometryn, simazine, simetryn, terbuthylazine and terbutryn.

In some of these examples, the gas chromatography assay employs an Agilent modified column based on the less polar DB-5 series, and more preferably a DB-UI8270D column.

In some of these embodiments, the temperature-increasing program for the column temperature of the gas chromatography comprises: the initial temperature is 75-85 ℃, the temperature is increased to 180 +/-5 ℃ at 30 +/-2 ℃/min, and the temperature is maintained for 2 +/-0.2 min; heating to 200 + -5 deg.C at 1.5 + -0.2 deg.C/min, and heating to 280 + -5 deg.C at 30 + -2 deg.C/min.

In some of these embodiments, the extraction solvent is a mixed n-hexane-acetone solution.

In some embodiments, the volume ratio of n-hexane to acetone in the n-hexane-acetone mixed solution is 1: (1. + -. 0.2).

In some of the embodiments described herein, the first and second,

the mass-to-charge ratio of the qualitative ions of the atranone is 211 to 197, and the mass-to-charge ratio of the quantitative ions is 196;

the mass-to-charge ratio of the put-out qualitative ions is 225 and 168, and the mass-to-charge ratio of the quantitative ions is 210;

the mass-to-charge ratio of the qualitative ions of the simazine is 186 and 173, and the mass-to-charge ratio of the quantitative ions is 201;

the mass-to-charge ratio of qualitative ions of the atrazine is 200 and 173, and the mass-to-charge ratio of quantitative ions is 215;

the mass-to-charge ratio of the qualitative ions of the prometryn is 229 to 172, and the mass-to-charge ratio of the quantitative ions is 214;

the mass-to-charge ratio of the qualitative ions of terbuthylazine is 229 and 173, and the mass-to-charge ratio of the quantitative ions is 214;

the mass-to-charge ratio of the qualitative ions of simetryn is 170 and 198, and the mass-to-charge ratio of the quantitative ions is 213;

the mass-to-charge ratio of the ametryn qualitative ions is 212 and 185, and the mass-to-charge ratio of the quantitative ions is 227;

the mass-to-charge ratio of the prometryn qualitative ions is 184 and 226, and the mass-to-charge ratio of the quantitative ions is 241;

the mass-to-charge ratio of the qualitative ions of the desmetryn is 241 and 185, and the mass-to-charge ratio of the quantitative ions is 226;

the mass-to-charge ratio of the qualitative ions of the internal standard quintozene is 248 and 213, and the mass-to-charge ratio of the quantitative ions is 237.

In some of these embodiments, the temperature of the extraction is 60 to 120 ℃, preferably 70 to 90 ℃.

In some of these embodiments, the purification uses a magnesium silicate solid extraction column as the purification column, and the volume ratio of activation to eluent is 1: (8-10) an acetone-n-hexane mixture.

In some of these embodiments, the concentration is a nitrogen-blown concentration at a pressure of (4.0 + 1) psi and the temperature of the nitrogen-blown concentration is (40.0 + 5) deg.C.

In some of these embodiments, the gas chromatography conditions of the gas chromatography assay comprise:

sample inlet temperature: (250 +/-10) DEG C, and no flow distribution;

sample introduction amount: (1.0 +/-0.1) mu L;

column flow rate: (0.8 +/-0.1) mL/min and constant current.

In some of these embodiments, the mass spectrometric conditions comprise:

an ion source: an electron bombardment source;

ion source temperature: (230 + -5) deg.C;

interface temperature: (280 + -5) deg.C;

quadrupole temperature: (150 + -5) deg.C;

solvent delay time: (6 +/-0.5) min;

scanning mode: and selecting ion SIM mode collection.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a method for detecting triazine pesticides in soil, which comprises the steps of selecting a pressurized solvent for extraction, combining gas chromatography mass spectrometry for detection, selecting a n-hexane-acetone mixed solution or acetonitrile as an extraction solvent for pressurized solvent extraction, particularly selecting the n-hexane-acetone mixed solution as the extraction solvent, and combining the specific chromatographic column type and a heating program, thereby finally realizing good peak shape of a chromatographic peak, high separation degree of each substance, and good sensitivity and accuracy.

In the method of the present invention, the inventors found that the kind of the column and the temperature raising procedure have a very important influence on the peak type of the chromatographic peak and the separation of the chromatographic peak. On the basis of the method, a chromatographic column is selected as DB-UI8270D, a specific temperature rise program is matched (the initial temperature is 75-85 ℃, the temperature is increased to (180 +/-5) ° C in (30 +/-2) ° C/min, the temperature is kept for (2 +/-0.2) min, the temperature is increased to (200 +/-5) ° C in (1.5 +/-0.2) ° C/min, and the temperature is increased to (280 +/-5) ° C in (30 +/-2) ° C/min), so that the peak pattern of a chromatographic peak can be good, and the separation degree of each substance is high.

Drawings

FIG. 1 is a total ion flow chromatogram of triazine pesticide of example 1 (column: DB-UI8270D), 1-atrazine; 2-prometon + simazine; 3-atrazine; 4-propazine; 5-pentachloronitrobenzene (internal standard); 6-terbuthylazine; 7-simetryn; 8-ametryn; 9-prometryn; 10-weeding agent;

FIG. 2 is a total ion flow chromatogram of triazine pesticide of example 2 (column: DB-5MSUI), 1-atranone; 2-prometon + simazine; 3-atrazine; 4-propazine; 5-terbuthylazine; 6-pentachloronitrobenzene (internal standard); 7-simetryn; 8-ametryn; 9-prometryn; 10-weeding agent;

figure 3 is the recovery of triazine pesticide from pressurized solvent extraction of the different solvent systems of example 3 (n-3);

figure 4 is the triazine pesticide recovery (n-3) for different pressurized solvent extraction temperatures of example 5;

figure 5 shows the recovery of triazine pesticide at different nitrogen sparge temperatures (n-3) for example 6;

figure 6 shows the recovery of triazine pesticide from example 7 at different nitrogen sparge pressures (n-3);

fig. 7 shows the recovery yield of triazine pesticide for different forms of soil of example 8 (n ═ 6);

fig. 8 is a total ion flux chromatogram of the triazine pesticide of comparative example 1.

Detailed Description

Experimental procedures according to the invention, in which no particular conditions are specified in the following examples, are generally carried out under conventional conditions, or under conditions recommended by the manufacturer. The various chemicals used in the examples are commercially available.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, article, or device that comprises a list of steps is not limited to only those steps or modules listed, but may alternatively include other steps not listed or inherent to such process, method, article, or device.

The "plurality" referred to in the present invention means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

The embodiment provides a method for detecting triazine pesticides in soil, which comprises the following steps:

preparation of sample solution to be tested: taking a soil sample, carrying out pressurized solvent extraction by using an extraction solvent, purifying and concentrating the obtained extracting solution, and adding an internal standard of quintozene to be used as a sample solution to be detected;

performing gas chromatography determination and mass spectrometry determination on the sample solution to be detected;

wherein the extraction solvent is n-hexane-acetone mixed solution or acetonitrile;

the triazine pesticide is at least one of ametryn, atrazine, prometon, prometryn, simazine, simetryn, terbuthylazine and terbutryn.

In some preferred embodiments, the extraction solvent is a n-hexane-acetone mixed solution; preferably, the volume ratio of n-hexane to acetone in the n-hexane-acetone mixed solution is 1: (1. + -. 0.2). Selecting n-hexane: acetone is used as an extraction solvent, so that the operation is simpler and more convenient, and the influence on the recovery rate is less.

In some preferred embodiments, the chromatographic column used in the gas chromatography assay is an Agilent modified chromatographic column based on the less polar DB-5 series, more preferably a DB-UI8270D chromatographic column. The column was selected as DB-UI8270D, and the separation efficiency and peak pattern were better than other columns such as DB-5 MSUI.

In some preferred embodiments, the temperature-raising program for the column temperature of the gas chromatography comprises: the initial temperature is 75-85 ℃, the temperature is increased to 180 +/-5 ℃ from (30 +/-2) ° c/min, the temperature is maintained for (2 +/-0.2), the temperature is increased to (200 +/-5 ℃) from (1.5 +/-0.2) ° c/min, and the temperature is increased to (280 +/-5) ° c from (30 +/-2) ° c/min. The method selects the temperature-raising program, all the objects to be measured can generate peaks, and the separation degree reaches the optimal state.

In some preferred embodiments, the temperature of the extraction is 60 to 120 ℃, preferably 70 to 90 ℃. The recovery rate is more ideal when the extraction is carried out at 70-90 ℃.

The present invention will be described in further detail with reference to specific examples.

Example 1

1. Main instrument and reagent

Gas chromatography-mass spectrometer (7890B-5977B, Agilent); ASE350 accelerated solvent extractor (semer fly); AUTO EVA-60 nitrogen-blown concentrator (Rui Ke instruments Co.); solid phase extraction apparatus (Shanghai' an spectral Co.); magnesium silicate SPE purification columns (1000mg, 6mL, Shanghai' an Spectrum Corp.); a freeze drier (Ningbo Xinzhi Biotech Co., Ltd.).

N-hexane (pesticide residue grade, shanghai' an spectral company); acetone (pesticide residue grade, shanghai' an spectral company); diatomaceous earth (AR grade, chemical agents corporation, national drug group); anhydrous sodium sulfate (AR grade, guangzhou chemical reagent plant); 10 triazine pesticide mixed standard solutions (containing ametryn, atrazine, prometon, prometryn, simazine, simetryn, terbuthylazine, desmetryn, 500mg/L, Chemservice company), quintozene (internal standard, 1000mg/L, Shanghai' an spectral analysis company).

2. Experimental procedure

2.1 sample Collection

Soil samples were collected in Yushu parks, Guangzhou (113.4334 ℃ E., 23.1630 ℃ N) and stored in clean ground brown glass bottles. Sealing, protecting from light, and refrigerating (below 4 deg.C) during transportation.

2.2 sample treatment and determination

And removing foreign matters such as branches, leaves and stones in the soil sample, freeze-drying the soil sample, and preparing a homogeneous phase drying sample by a quartering method. A10 g (to the nearest 0.01g) sample of the soil was weighed into a mortar and a quantity of diatomaceous earth was added and ground into fine particles until well dispersed. The treated sample was transferred to the extraction cell of an ASE device, and after the instrument automatically added n-hexane/acetone mixed solution (1:1, V: V), pressurized solvent extraction was performed (extraction conditions were shown as 2.3). Collecting the extractive solution, purifying (under 2.4 for purification), collecting the eluate, concentrating the eluate by blowing with liquid nitrogen (under 2.5 for nitrogen blowing), adding internal standard, and diluting to 1mL for GC/MS analysis.

2.3ASE extraction conditions:

instrument system pressure: 1500 psi; extraction temperature: 80 ℃; heating time: 5 min; static extraction time: 5 min; the leaching volume of the solvent is as follows: 60 percent; nitrogen purging time: 60 s; the number of static extraction times is as follows: 2 times.

2.4 purification scheme

Selecting a magnesium silicate purifying column as a purifying column, and adding acetone: n-hexane (1: 9, V: V) is used as an activation and elution solution, wherein the addition amount in the activation process is 5mL (the activation is discarded, but the purification column needs to be kept soaked), and the addition amount in the elution process is 10 mL.

2.5 Nitrogen blowing concentration conditions

Nitrogen blowing pressure: 4.0 psi; nitrogen-blown concentration temperature: at 40.0 ℃.

2.6 gas chromatography conditions

Sample inlet temperature: no flow splitting at 250 ℃;

sample introduction amount: 1.0 μ L, column flow: 0.8mL/min (constant flow);

lining pipe: ultra-high inertia, single cone, glass wool (5190-;

a chromatographic column: DB-UI8270D (30 m.times.0.25 mm.times.0.25 μm, Agilent);

column temperature: the initial temperature is 80 ℃, the temperature is increased to 180 ℃ at 30 ℃/min, and the temperature is kept for 2 min; the temperature is raised to 200 ℃ at a rate of 1.5 ℃/min and to 280 ℃ at a rate of 30 ℃/min.

2.7 Mass Spectrometry conditions

An electron impact source (EI); ion source temperature: 230 ℃; interface temperature: 280 ℃; quadrupole temperature: 150 ℃; solvent delay time: 6 min; scanning mode: ion SIM mode acquisition was selected (see 3.3 for ions collected for each analyte).

3. Results and discussion

Fig. 1 is a total ion current chromatogram of triazine pesticide, and as can be seen from fig. 1, the separation between the peaks in fig. 1 is obvious, and the peak pattern is good. And figure 1 can be completely separated for peak 5 and peak 6.

3.1 extraction recovery

Taking n-hexane and acetone (1:1, V: V) as an extraction solvent system, and performing parallel determination for 3 times to obtain an average value. The experimental result (figure 3) shows that the extraction recovery rate of the target object is ideal when the normal hexane and the acetone (1:1, V: V) are used as the extraction system, and the recovery rate range is 87% -102%. And the purification step can be carried out without converting a solvent system after the extraction is finished, so that the influence on the recovery rate caused by the follow-up secondary concentration is avoided.

3.2 Mass Spectrometry feature ion selection of target Compounds

According to the instrument conditions, 10 mixed standard solutions of triazine herbicides and quintozene (internal standard) are diluted and then directly tested on a computer, and the total scanning mode (SCAN) is adopted, and the mass scanning range is as follows: 90amu to 260 amu. The ion response strength is used as a selection principle to establish the qualitative and quantitative ions of each substance, and the specific information is shown in Table 1. The appropriate segmentation window for the selective acquisition (SIM) mode is set according to the ion information of table 1, ensuring that all ion dwell times are between 30ms and 50ms, and the cycle time is greater than 3 Hz. The total ion current is schematically shown in FIG. 1. It can be seen that except for the promethazine and the terbuthylazine (the quantitative ions are the same), the characteristic qualitative and quantitative ions of the other substances to be tested are not repeated, and the qualitative identification and the quantitative test can be well carried out. The retention time of the promethazine and the terbuthylazine is different, so that the quantitative analysis of the two substances is not influenced. In addition, the qualitative and quantitative ions of the co-efflux prometon and simazine are different, so that the test result is not influenced.

TABLE 1 characteristic ion information of substances

3.3 Linear Range of method, correlation coefficient and Method Detection Limit (MDL)

The mixed standard series solution in the linear range of the method is subjected to sample injection analysis, the result takes the concentration of a target compound as a horizontal coordinate, the product of the ratio of the quantitative ion response value of the target compound and an internal standard compound and the mass concentration of the internal standard compound as a vertical coordinate, each object to be detected is in a good linear relation in the range of 0.05-5 mg/L, and the correlation coefficient (r) is greater than 0.997. The actual blank soil sample is normalized so that the triazine pesticide content is 0.01mg/kg (sample weighing is 10.0g), the standard deviation (S) is calculated by parallel analysis for 7 times, and the detection limit is calculated according to the method of the formula MDL (t-1, 0.99) multiplied by S (t is 3.143). The detection limit range of 10 triazine pesticides is between 0.002 and 0.003mg/kg, and the results are shown in Table 2. The detection limit is far lower than the detection limit range (0.02-0.08mg/kg) of the existing detection method, and the method has good sensitivity.

Table 2 regression equation, correlation coefficient and detection limit for the method (n ═ 7)

3.4 precision, accuracy and actual sample determination of the method

And (3) extracting, purifying and concentrating the soil sample according to a sample pretreatment method (2.2-2.5), analyzing and determining under instrument analysis conditions (2.6-2.7), and detecting no target object. The soil samples are subjected to standard adding measurement with high, medium and low concentrations of 0.02, 0.1 and 0.5mg/kg respectively, the Relative Standard Deviation (RSD) and the standard adding recovery rate are calculated, the analysis data can obtain the recovery rate of 10 triazine pesticides between 66.7 and 102 percent, the Relative Standard Deviation (RSD) range is between 0.79 and 5.49 percent, the accuracy is good, and the results are shown in Table 3.

Table 3 precision and recovery from spiking of the method (n ═ 6)

3.5 interference and control method

Other semi-volatile substances to be tested in soil can interfere the testing of triazines, wherein polycyclic aromatic hydrocarbons and phthalic acid esters belong to substances with high detection frequency, the following table 4 lists characteristic ions of mass spectra of the two substances, and as can be seen from the list, the characteristic ions of the substances are different from the characteristic ions (table 4) of triazine pesticides.

TABLE 416 polycyclic aromatic hydrocarbons and 6 phthalate esters characteristic ion information

Triazine pesticides are organic compounds having a high boiling point and are likely to remain in a GC/MS system. Cross-contamination may occur when high and low content samples are analyzed sequentially. In order to avoid cross contamination, a reagent is needed to clean the sample injection needle between two sample injections. When unconventional high concentration samples are tested, reagent blanks must be analyzed to check the system for cross-contamination.

The method adopts the ultrahigh inert liner tube and the chromatographic column when the GC/MS is used for testing the triazine pesticide, can avoid the interference of high-boiling-point pollutant residue in the soil matrix on the peak type, and can also maintain high sensitivity and reproducibility.

Example 2

This example differs from example 1 in that the column of example 1 was replaced with DB-5MSUI (30 m.times.0.25 mm.times.0.25 μm, Agilent).

The inventor selects a conventional DB-5MSUI chromatographic column for testing, the obtained triazine pesticide total ion chromatogram is shown in FIG. 2, the peak type and the separation degree of each peak are poor, particularly, the peak 5 and the peak 6 cannot be separated, the peak 6 is not obvious, other chromatographic columns cannot be solved after repeated attempts, finally, the modified chromatographic column DB-UI8270D based on a low-polarity DB-5 series (shown in example 1) of Agilent company is tried accidentally, the separation degree effect is good, the peak type is also good (shown in FIG. 1), and the results are found after repeated verification, and the inventor conjectures that the reason is that DB-UI8270D has higher inertia and can better reduce the interference of various types of active functional groups in a flow path according to the test results.

Example 3

This example is different from example 1 in the temperature raising program; the temperature raising procedure of the present embodiment is: the initial temperature is 100 ℃, the temperature is increased to 180 ℃ at the speed of 20 ℃/min, and the temperature is kept for 2 min; heating to 240 deg.C at 10 deg.C/min, and heating to 280 deg.C at 30 deg.C/min.

The result shows that all the samples can generate peaks under the condition of the temperature-rising program, but 10 samples can generate peaks all within 7.5-10.5 min, and the separation degree is poor.

Example 4

This example differs from example 1 in that acetone (1:1, V: V) as the extraction solvent for the pressurized solvent extraction was replaced with acetonitrile.

In this test, the n-hexane of example 1 and acetone (1:1, V: V), the acetonitrile of example 3 and the acetone and dichloromethane (1:1, V: V) (control) were used as solvent systems, and the results were measured in parallel 3 times, and the extraction effects were compared by taking the mean values. The experimental result (figure 3) shows that the extraction recovery rate of the target object is ideal by the three solvent systems. Respectively recovering 87-102 percent of normal hexane and acetone (1:1, V: V), 89-105 percent of acetonitrile system and 86-104 percent of acetone and dichloromethane (1:1, V: V). The extraction effect of the acetonitrile system is the best, and the normal hexane acetone in the example 1 is basically equivalent to the reference acetone dichloromethane. However, the boiling point of acetonitrile is higher, the concentration time is 5 times longer than that of the other two systems, and after the extraction of the acetone-dichloromethane (1:1, V: V) system is finished, the solvent system needs to be converted to normal hexane for purification, and the process relates to secondary concentration and influences the recovery rate.

Example 5

This example differs from example 1 in that: the extraction temperature is 60 ℃, 100 ℃ or 120 ℃.

The effect of the pressurized solvent extraction at four temperatures of 60 ℃, 100 ℃, 120 ℃ and 80 ℃ in example 1 was measured, and the results were measured in parallel 3 times at each temperature, and the average value was obtained.

The experimental results (as shown in fig. 4) show that the extraction recovery rates at 60 ℃, 80 ℃, 100 ℃ and 120 ℃ are 93.4% -112%, 94.1% -115%, 91.2% -112% and 88.2% -109%, respectively, and it can be seen that the extraction recovery rate at 80 ℃ in example 1 is relatively ideal, and the inventors found in the research that the recovery rate slightly decreases with the increase of the extraction temperatures at 100 ℃ and 120 ℃.

Example 6

This example differs from example 1 in that the nitrogen blowing temperature was 35 ℃ or 45 ℃.

The nitrogen recovery rate at the nitrogen blowing temperature of 35 ℃ and 45 ℃ was examined, and the nitrogen recovery rate was measured 3 times in parallel at each nitrogen blowing temperature, and the average value was taken. As shown in FIG. 5, the nitrogen recovery rates at 35 deg.C, 40 deg.C and 45 deg.C were 88-104%, 92-106% and 90-105%, respectively. The recovery rate at 35 ℃ and 45 ℃ is slightly poor, and the nitrogen blowing recovery rate at 40 ℃ is comprehensive and better.

Example 7

This example differs from example 1 in that the nitrogen blowing pressure was 3.0psi or 5.0 psi.

The nitrogen recovery rate at a nitrogen blowing pressure of 3.0psi or 5.0psi was examined, and the nitrogen recovery rate was measured 3 times in parallel at each nitrogen blowing pressure, and the average value was taken. Experiments show (figure 6), the nitrogen blowing recovery rates under 3.0psi, 4.0psi (example 1) and 5.0psi are respectively 92% -102%, 92% -104% and 93% -109%, and it can be seen that the change of the nitrogen blowing pressure has no great influence on the recovery rate of the object to be measured, and the comprehensive effect of 4.0psi is the best by comprehensively considering the measurement efficiency and the measurement cost.

Example 8

A triazine pesticide standard solution (the addition amount is 1.0 mu g) is added into a soil sample, extraction, concentration, purification and on-machine analysis are carried out according to example 1, the applicability of 3 different forms of soil (sandy soil, loam and clay) to the method of example 1 is examined, the soil of each form is measured in parallel 6 times, and the average value is taken. The experimental results (figure 7) show that the standard recovery rates of sandy soil, loam and clay are 73.9-96.3%, 70.3-91.1% and 61.3-79.9% respectively, and it can be seen that the method has good applicability to the soils with different forms.

Comparative example 1

This comparative example differs from example 1 in that the column of example 1 was replaced with DB-5MSUI (30 m.times.0.25 mm.times.0.25 μm, Agilent) and the temperature program was controlled as follows: the initial temperature is 100 ℃, the temperature is increased to 180 ℃ at the speed of 20 ℃/min, and the temperature is kept for 2 min; heating to 240 deg.C at 10 deg.C/min, and heating to 280 deg.C at 30 deg.C/min.

The results are shown in fig. 8, where the peak time was very concentrated and most of the material did not reach baseline separation, the separation was poor.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A method for detecting triazine pesticides in soil is characterized by comprising the following steps:

preparation of sample solution to be tested: taking a soil sample, carrying out pressurized solvent extraction by using an extraction solvent, purifying and concentrating the obtained extracting solution, and adding an internal standard of quintozene to be used as a sample solution to be detected;

performing gas chromatography determination and mass spectrometry determination on the sample solution to be detected;

wherein the extraction solvent is n-hexane-acetone mixed solution or acetonitrile;

the triazine pesticide is at least one of ametryn, atrazine, prometon, prometryn, simazine, simetryn, terbuthylazine and terbutryn.

2. The detection method according to claim 1, wherein the chromatographic column used in the gas chromatography assay is an Agilent modified chromatographic column based on the weakly polar DB-5 series, more preferably a DB-UI8270D chromatographic column.

3. The detection method according to claim 1, wherein the temperature raising program for the column temperature of the gas chromatography comprises: the initial temperature is 75-85 ℃, the temperature is increased to 180 +/-5 ℃ from (30 +/-2) ° c/min, the temperature is maintained for (2 +/-0.2), the temperature is increased to (200 +/-5 ℃) from (1.5 +/-0.2) ° c/min, and the temperature is increased to (280 +/-5) ° c from (30 +/-2) ° c/min.

4. The detection method according to claim 1, wherein the extraction solvent is a n-hexane-acetone mixed solution; preferably, the volume ratio of n-hexane to acetone in the n-hexane-acetone mixed solution is 1: (1. + -. 0.2).

5. The detection method according to claim 1, wherein the temperature of the extraction is 60 to 120 ℃, preferably 70 to 90 ℃.

6. The detection method according to claim 1,

the mass-to-charge ratio of the qualitative ions of the atranone is 211 to 197, and the mass-to-charge ratio of the quantitative ions is 196;

the mass-to-charge ratio of the put-out qualitative ions is 225 and 168, and the mass-to-charge ratio of the quantitative ions is 210;

the mass-to-charge ratio of the qualitative ions of the simazine is 186 and 173, and the mass-to-charge ratio of the quantitative ions is 201;

the mass-to-charge ratio of qualitative ions of the atrazine is 200 and 173, and the mass-to-charge ratio of quantitative ions is 215;

the mass-to-charge ratio of the qualitative ions of the prometryn is 229 to 172, and the mass-to-charge ratio of the quantitative ions is 214;

the mass-to-charge ratio of the qualitative ions of terbuthylazine is 229 and 173, and the mass-to-charge ratio of the quantitative ions is 214;

the mass-to-charge ratio of the qualitative ions of simetryn is 170 and 198, and the mass-to-charge ratio of the quantitative ions is 213;

the mass-to-charge ratio of the ametryn qualitative ions is 212 and 185, and the mass-to-charge ratio of the quantitative ions is 227;

the mass-to-charge ratio of the prometryn qualitative ions is 184 and 226, and the mass-to-charge ratio of the quantitative ions is 241;

the mass-to-charge ratio of the qualitative ions of the desmetryn is 241 and 185, and the mass-to-charge ratio of the quantitative ions is 226;

the mass-to-charge ratio of the qualitative ions of the internal standard quintozene is 248 and 213, and the mass-to-charge ratio of the quantitative ions is 237.

7. The detection method according to any one of claims 1 to 6, wherein the purification uses a magnesium silicate solid extraction column as a purification column, and the volume ratio of the activation and elution solution used for the purification is 1: (8-10) an acetone-n-hexane mixture.

8. The detection method according to any one of claims 1 to 6, wherein the concentration is a nitrogen-blown concentration, the pressure of the nitrogen-blown concentration is (4.0 ± 1) psi, and the temperature of the nitrogen-blown concentration is (40.0 ± 5) ° C.

9. The detection method according to any one of claims 1 to 6, wherein the gas chromatography conditions of the gas chromatography measurement include:

sample inlet temperature: (250 +/-10) DEG C, and no flow distribution;

sample introduction amount: (1.0 +/-0.1) mu L;

column flow rate: (0.8 +/-0.1) mL/min and constant current.

10. The detection method according to any one of claims 1 to 6, wherein the mass spectrometric conditions comprise:

an ion source: an electron bombardment source;

ion source temperature: (230 + -5) deg.C;

interface temperature: (280 + -5) deg.C;

quadrupole temperature: (150 + -5) deg.C;

solvent delay time: (6 +/-0.5) min;

scanning mode: and selecting ion SIM mode collection.

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