CN103926347A

CN103926347A - Quantitative detection method for organophosphorus pesticide in soil

Info

Publication number: CN103926347A
Application number: CN201410168315.7A
Authority: CN
Inventors: 杨代凤; 刘腾飞; 董明辉; 陆皓茜; 邓金花; 张丽; 顾俊荣
Original assignee: TAIHU LAKE AREA INSTITUTE OF AGRICULTURAL SCIENCES
Current assignee: TAIHU LAKE AREA INSTITUTE OF AGRICULTURAL SCIENCES
Priority date: 2014-04-24
Filing date: 2014-04-24
Publication date: 2014-07-16
Anticipated expiration: 2034-04-24
Also published as: CN103926347B

Abstract

The invention discloses a quantitative detection method for an organophosphorus pesticide in soil. The method is characterized by comprising the following steps: carrying out ultrasonic extraction on a soil sample by using an acetonitrile solution of which the volume fraction is 1%; purifying by using proper mixed filler of PSA and C18; carrying out nitrogen blowing and concentrating on supernate until nearly dry; respectively dissolving and making to constant volume by using normal hexane; heating up and separating by using DB-1701 quartz capillary column program; carrying out GC/FPD detection; finally quantifying by using a matrix external standard method. A test proves that the method is wide in linear range, the technical indicators such as the detection sensitivity, the accuracy and the precision meet the requirements of residue analysis, the quantitative detection method is simple in pre-treatment operation, convenient and fast, and reliable means is provided for analysis and research of organophosphorus pesticide residue in the soil.

Description

The quantitative detecting method of organophosphorus insecticide in a kind of soil

Technical field

The present invention relates to the detection method field of persticide residue, be specifically related to the quantitative detecting method of organophosphorus insecticide in a kind of soil, this quantitative detecting method is to adopt improved QuEChERS method that soil is extracted, purified, by vapor-phase chromatography, organophosphorus insecticide is detected again, to reach quick, easy, reliable object.

Background technology

Organophosphorus pesticide (Organophosphorus pesticides) is a class chemical pesticide of current China each department widespread use, there is the features such as wide spectrum, efficient, economic, wide in variety, consumption are few, to control disease pest and weed, guarantee that crop yield brought into play vital role.But studies confirm that this class agricultural chemicals can produce toxic action to the nervous system of human body, that part kind has is carcinogenic, teratogenesis, mutagenesis and certain property accumulated, and excessive use is likely accumulated in human body, causes chronic accumulate poisoning.In crop pest control process, directly be scattered in agricultural chemicals ratio on target organisms seldom, major part enters in soil by all means, and organophosphorus pesticide fat-soluble stronger can be adsorbed in soil for a long time, cause Soil Contamination by Chemical Pesticides, geobiont is worked the mischief, affect soil fertility, and can pass through the approach polluted-waters such as runoff, leaching and affect hydrobiont, and by biological concentration and the enlarge-effect of food chain, be finally detrimental to health.Therefore the residual of this class agricultural chemicals in soil detected, monitored, contribute to evaluate its residual situation in soil, to adopting an effective measure, remove and to alleviate pollution by pesticides significant.

Soil is because self component is complicated, and interfering material is more, easily causes agricultural chemicals extraction and cleaning difficulty, and therefore selecting suitable sample-pretreating method is the primary committed step that Pesticide-Polluted Soil detects.In Pesticide-Polluted Soil leaching process, existing report mainly uses the methods such as traditional Soxhlet extraction, liquid-liquid extraction, microwave abstracting, accelerated solvent extraction.Although extracting, Soxhlet there is good extraction effect, but length consuming time (being generally 10～24h), organic solvent consumption large (consumption is 50～400mL conventionally), be unsuitable for the pre-treatment of batch sample, and for a long time Soxhlet leaching process easily causes the decomposition of some agricultural chemicals, causes the recovery on the low side; Although liquid-liquid extraction equipment is simple, technology maturation, solvent-oil ratio is large, loaded down with trivial details time-consuming, and easily produces a large amount of emulsion fluid in extraction process, affects extraction efficiency, causes the recovery to decline; Microwave abstracting and accelerated solvent extraction solvent load are few, and extraction efficiency is high, but need expensive extraction instrument, operating cost is high, some extraction processes also need at high temperature to carry out, easily thermo-responsive agricultural chemicals impacted, and the more loaded down with trivial details purifying step of follow-up common needs.In the purification process of Pesticide-Polluted Soil, current purification method adopts solid phase extraction column method, column chromatography and concentrated acid sulfonation method more.Solid phase extraction column solvent load is few, simple to operate, and the recovery is high, is easy to automation mechanized operation, but cost is higher; Column chromatography purifies more complete, be applicable to the retention analysis of most of sample Pesticides, but solvent-oil ratio is large, and formality is loaded down with trivial details, to column packing technique, requires high; The clean-up effect of concentrated acid sulfonation is better, but applicable pesticide species is very limited, has the problems such as sour unstable agricultural chemicals decomposition, and the heat that concentrated sulfuric acid dissolution discharges can accelerate organic solvent volatilization, generation quantitative error.

Summary of the invention

The invention provides the quantitative detecting method of organophosphorus insecticide in a kind of soil, the detection method length consuming time, complex operation, consumption organic solvent that its object is to solve organophosphorus insecticide in existing mensuration soil mainly with and the problem such as testing result is reliable and stable not.

For achieving the above object, the technical solution used in the present invention is: the quantitative detecting method of organophosphorus insecticide in a kind of soil, and described quantitative detecting method is comprised of two parts:

First, sets up the typical curve of the tested organophosphorus pesticide of known gradient concentration by vapor-phase chromatography; The foundation of described typical curve is comprised of following steps:

The first step, prepares blank matrix extract, and preparation method is comprised of following steps:

(1) take 5.0g after measured not containing the blank pedotheque of tested organophosphorus pesticide in 50mL centrifuge tube, in centrifuge tube, add 2mL ultrapure water again, vortex mixes, and infiltrates 10～20min, then adds 10mL to contain the acetonitrile solution that volume fraction is 1% acetic acid, mix, ultrasonic extraction 10～15min, adds 2g anhydrous sodium acetate and 2g anhydrous magnesium sulfate, vortex 2min, with the centrifugal 4min of 9000r/min rotating speed, get supernatant and be blank matrix extract to be clean;

(2) separately get a 10mL centrifuge tube, add 0.15g C18,0.15g N-propyl group ethylenediamine and 0.3g anhydrous magnesium sulfate, add blank matrix extract to be clean described in 4mL, vortex 1.5min～2.5min, with the centrifugal 4.5min～5.5min of rotating speed of 9000r/min; After centrifugal, pipette 2.0mL supernatant to scale test tube, then under 50～60 ℃ of water-baths, supernatant is slowly blown to 50～70 μ L with nitrogen; In supernatant, add again acetone to be settled to 1.0mL, cross after organic system filter membrane, obtain for preparing the blank matrix extract of organophosphorus pesticide;

Second step, the blank matrix extract obtaining in the described first step of take is the matrix hybrid standard working solution of solvent preparation organophosphorus pesticide, wherein, described organophosphorus pesticide refers to DDVP, Rogor, chlopyrifos, parathion-methyl, malathion, fenifrothion, Hostathion; In the matrix hybrid standard working solution of described organophosphorus pesticide, the concentration range of each organophosphorus pesticide is:

The 3rd step, chromatographic peak retention time and chromatographic peak area with each pesticide composition in the matrix hybrid standard working solution of organophosphorus pesticide described in gas chromatography determination, qualitative with chromatographic peak retention time, then take mass concentration as horizontal ordinate, the chromatographic peak area of take is drawn out the typical curve of organophosphorus pesticide as ordinate;

Wherein, the chromatographic condition of mensuration organophosphorus pesticide is:

Chromatographic column: the capillary chromatographic column that model is DB-1701, specification is 30m * 0.32mm * 0.25 μ m; Sample size: 1.0 μ L, Splitless injecting samples; Injector temperature: 220 ℃, dottle pin purges 3mL/min; Column temperature: 90 ℃ of initial temperatures, keep 1min, 20 ℃/min rises to 200 ℃, keeps 9min, and 30 ℃/min rises to 245 ℃, keeps 8min; Carrier gas: high pure nitrogen, purity >=99.999%; Constant current mode, flow velocity 3mL/min; Detecting device: flame photometric detector (FPD); Detector temperature: 245 ℃; Hydrogen: flow is 75mL/min; Air: flow is 100mL/min; Make-up gas: high pure nitrogen, flow is 60mL/min;

Second portion, measures 7 kinds of organophosphorus pesticide residual quantities in first described in pedotheque, and quantitative detecting method comprises the following steps:

The first step, extracts pedotheque;

Take the pedotheque of having pulverized, be placed in 50mL centrifuge tube, in centrifuge tube, add 2mL ultrapure water again, vortex mixes, and infiltrates 10～20min, then to add containing volume fraction be the acetonitrile solution of 1% acetic acid, wherein, the input ratio of described pedotheque and described acetonitrile solution, for to dropping into acetonitrile solution described in 1mL in every 0.5g pedotheque, mixes ultrasonic extraction 10～15min; Add again anhydrous sodium acetate and anhydrous magnesium sulfate, wherein, described pedotheque, anhydrous sodium acetate and anhydrous magnesium sulfate three's mass ratio is 5:2:2, vortex 1.5min～2.5min, with the centrifugal 3.5min～4.5min of rotating speed of 9000r/min, get supernatant and be pedotheque extract to be clean;

Second step, purifies described pedotheque extract to be clean;

Separately get a 10mL centrifuge tube, add C18, N-propyl group ethylenediamine and anhydrous magnesium sulfate, add described pedotheque extract to be clean, wherein, the content of C18, N-propyl group ethylenediamine and the anhydrous magnesium sulfate dropping in pedotheque extract to be clean is respectively 37.5mg/mL, 37.5mg/mL and 75mg/mL, vortex 1.5min～2.5min, with the centrifugal 4.5min～5.5min of rotating speed of 9000r/min; After centrifugal, pipette 2.0mL supernatant to scale test tube, under 50～60 ℃ of water-baths, supernatant is slowly blown to 50～70 μ L with nitrogen; In supernatant, add again acetone to be settled to 1.0mL, cross after organic system filter membrane, obtain for measuring the pedotheque extraction and cleaning liquid of organophosphorus pesticide;

The 3rd step, with the organophosphorus pesticide in pedotheque extraction and cleaning liquid described in gas chromatography determination, record chromatographic peak retention time and chromatographic peak area, after qualitative by chromatographic peak retention time, the typical curve of the organophosphorus pesticide that the detected chromatographic peak area of described pedotheque extraction and cleaning liquid and described first are obtained compares, and obtains the measured value of every kind of organophosphorus pesticide containing in described pedotheque extraction and cleaning liquid; Again described measured value is brought in quantitative computing formula, finally obtains organophosphorus pesticide residual quantity to be measured in pedotheque;

Quantitative computing formula: ω=(ρ * v * f)/m, in formula: ω is organophosphorus pesticide residual quantity to be measured in pedotheque, and unit is mg/kg; ρ is measured value, and unit is mg/L; M is the sample size taking, and unit is g; V is constant volume, and unit is mL; F is extension rate;

Wherein, measure the chromatographic condition of the organophosphorus pesticide in the chromatographic condition of the organophosphorus pesticide in described pedotheque extraction and cleaning liquid and the 3rd step of described first identical.

Related content in technique scheme is explained as follows:

1, in such scheme, preferably scheme be the condition of ultrasonic extraction in the first step of described first and the first step of described second portion be ultrasonic power between 80W～100W, ultrasonic temperature is at 20～30 ℃.

2,, in such scheme, the standard reserving solution mass concentration of described DDVP, Rogor, chlopyrifos, parathion-methyl, malathion, fenifrothion, these 7 kinds of agricultural chemicals of Hostathion is 1000mg/L, is purchased from Inst. of Environment Protection & Scientific Research Monitor, Ministry of Agric;

Acetone is HPLC level, and manufacturer is Shanghai Chemical Reagent Co., Ltd., Sinopharm Group; N-propyl group ethylenediamine (English referred to as PSA), particle diameter is 40～60 μ m, manufacturer is U.S. AgelaTechnologies company; C18, aperture 6nm, granularity 40～60 μ m, manufacturer is U.S. SepaxTechnologies company; Acetonitrile, acetic acid, anhydrous sodium acetate, anhydrous magnesium sulfate, all need be analysis pure at 620 ℃ of calcination 4h, and manufacturer is Shanghai Chemical Reagent Co., Ltd., Sinopharm Group; Experimental water is ultrapure water (18.4M Ω).

3, in such scheme, before the matrix hybrid standard working solution of preparation organophosphorus pesticide, first prepare organophosphorus pesticide hybrid standard storing solution, agricultural chemicals hybrid standard storing solution prepares to be placed in 4 ℃ of refrigerators and preserves, and the blank matrix extract of take during use is mixed with the agricultural chemicals matrix hybrid standard working solution of debita spissitudo as solvent;

Wherein, the compound method of organophosphorus pesticide hybrid standard storing solution is: 7 kinds of organophosphorus pesticide standard reserving solution concentration are 1000mg/L, get respectively 1mL and are placed in 5mL volumetric flask, use acetone diluted constant volume, being mixed with concentration is single mark solution of 200mg/L, in-20 ℃ of lucifuge sealings, preserves.Response according to each agricultural chemicals on FPD detecting device, single mark solution DDVP is got 0.5mL, and Rogor, Hostathion are respectively got 2mL, and all the other organophosphorus list mark solution are respectively got 1mL, are placed in 10mL volumetric flask, use acetone constant volume.In 7 kinds of organophosphorus pesticide hybrid standard storing solutions: DDVP concentration is 10mg/L, chlopyrifos, parathion-methyl, fenifrothion, malathion concentration are respectively 20mg/L, and Rogor, Hostathion concentration are respectively 40mg/L.

4, in such scheme, use 7 kinds of organophosphorus pesticides of gas chromatography determination, qualitative with retention time, peak area external standard method is quantitative.

Principle of work of the present invention and beneficial effect are: 2003, the people such as Anastassiades M of agricultural research service centre of United States Department of Agriculture have proposed (Quick of a kind of being called as " QuEChERS ", Easy, Cheap, Effective, Rugged and Safe) many residual sample of novel agrochemical preparation method.The method dirigibility is strong, and applied range can be per sample and the feature of target analytes, select applicable extraction solvent and purify filler, there is the advantages such as quick, easy, efficient, safe, in food security field, be widely applied, and application report in soil is less.

Deficiency for organophosphorus insecticide pre-treatment complex operation, and soil matrix is complicated, factor and less these present situations of examination criteria such as chaff interference is more, method that the present invention adopts improved " QuEChERS ", the extraction and purification methods of this class agricultural chemicals is carried out to combination, use capillary gas chromatography, at the upper content of measuring of detecting device FPD (being gas chromatographic flame photometric detector), set up the how residual quantitative detecting method of organophosphorus insecticide in soil, method is fast and convenient, save time reliable, improved accuracy of analysis, reduced experimentation cost, for soil quality is controlled monitoring method and the foundation that science is provided, there is certain popularizing value.

Soil pattern is the ultrasonic extraction of acetonitrile solution of 1% acetic acid with containing volume fraction, then purifies with appropriate PSA and C18 mixed fillers, and supernatant liquid nitrogen blows concentrated near dry, use acetone solution constant volume, DB-1701 quartz capillary column and programmed temperature is separated, and GC/FPD detects, and finally uses matrix external standard method quantitative.Adopt the calibration of matrix matching standard solution quantitatively, reduced the matrix effect of agricultural chemicals to be measured, measurement result is more accurate.By test, confirm, the method range of linearity is wide, and the technical indicators such as detection sensitivity, accuracy and precision all meet the requirement of retention analysis, for the analysis and research of organophosphorus pesticide residue in soil especially tea garden soil provide reliable means.

Compare with national standard method with existing Pesticide-Polluted Soil detection method, pre-treatment of the present invention is simple to operate, and extraction and cleanup only needs several steps to complete, and adopting ultrasonic method while extracting, result is stable, reproducible, facilitate the processing of follow-up batch sample, practicality is stronger; Purification process avoids using decontaminating column and a large amount of solvent elution, and agricultural chemicals loss is few, and the recovery is high, and the time and the organic solvent that expend greatly reduce simultaneously, save testing cost, and environmental pollution is little, also safer to operator.Detect and analyze the conventional gas chromatograph (being furnished with FPD) in employing laboratory, moderate cost, Operation and Maintenance is simple, and technical requirement is strict not as application of gas chromatorgraphy/mass, is more suitable for applying in testing agency of vast basic unit.Quantivative approach adopts the calibration of matrix matching standard solution quantitatively, has reduced the matrix effect of agricultural chemicals to be measured, and measurement result is more accurate.Quantitative detecting method fast and easy of the present invention, and on the indices such as accuracy, precision, sensitivity, all meet the requirement that pesticide multi-residues is analyzed, for soil quality, control monitoring method and the foundation that science is provided, there is certain popularizing value.

Accompanying drawing explanation

Accompanying drawing 1 is the matrix hybrid standard working solution chromatogram of 7 kinds of organophosphorus pesticides in the embodiment of the present invention;

Accompanying drawing 2 is 7 kinds of agricultural chemicals matrix effect figure in soil in the embodiment of the present invention;

Accompanying drawing 3 is that in the embodiment of the present invention, the soil for the recovery and precision mensuration adds 7 kinds of organophosphorus pesticide standard colors spectrograms.

Embodiment

Below in conjunction with drawings and Examples, the invention will be further described:

Embodiment: the quantitative detecting method of organophosphorus insecticide in a kind of soil

For examination soil, be yellow soil, gather from the tea place in area, Dongshan, Suzhou, sampling depth is 0～15cm.Soil sample is removed to the foreign material such as grass roots, stone, manually smash to pieces, in basin or other appropriate vessel, fully mix, by inquartation, get a certain amount of standby, the pedotheque preparing should be analyzed as early as possible, otherwise put into-20 ℃ of refrigerators, preserves, and physiochemical properties of soil is: pH4.1～4.7, clay content 14%～17%, the content of organic matter 23.41～59.83g/kg.Described quantitative detecting method is comprised of two parts:

(1) take 5.0g after measured not containing the blank pedotheque of tested organophosphorus pesticide in 50mL centrifuge tube, in centrifuge tube, add 2mL ultrapure water again, vortex mixes, infiltrate 15min, add again 10mL to contain the acetonitrile solution that volume fraction is 1% acetic acid, mix, ultrasonic extraction 10～15min, ultrasonic power is between 80W～100W, ultrasonic temperature, at 20～30 ℃, adds 2g anhydrous sodium acetate and 2g anhydrous magnesium sulfate, vortex 2min, with the centrifugal 4min of 9000r/min rotating speed, get supernatant and be blank matrix extract to be clean;

(2) separately get a 10mL centrifuge tube, add 0.15g C18,0.15g N-propyl group ethylenediamine and 0.3g anhydrous magnesium sulfate, add blank matrix extract to be clean described in 4mL, vortex 1.5min～2.5min, with the centrifugal 5min of rotating speed of 9000r/min; After centrifugal, pipette 1.5mL supernatant to scale test tube, then under 50～60 ℃ of water-baths, supernatant is slowly blown to 50～70 μ L with nitrogen; In supernatant, add again acetone to be settled to 0.75mL, cross after 0.22 μ m organic system filter membrane, obtain for preparing the blank matrix extract of organophosphorus pesticide;

The first step, extracts pedotheque;

Take the 5.0g pedotheque of having pulverized, be placed in 50mL centrifuge tube, in centrifuge tube, add 2mL ultrapure water again, vortex mixes, and infiltrates 15min, then adds 10mL to contain the acetonitrile solution that volume fraction is 1% acetic acid, mix, ultrasonic extraction 10～15min, ultrasonic power is between 80W～100W, and ultrasonic temperature is at 20～30 ℃; Add 2g anhydrous sodium acetate and 2g anhydrous magnesium sulfate, vortex 2min, with the centrifugal 4min of rotating speed of 9000r/min, gets supernatant and is pedotheque extract to be clean again;

Second step, purifies described pedotheque extract to be clean;

Separately get a 10mL centrifuge tube, add 0.15g C18,0.15g N-propyl group ethylenediamine (the English PSA of abbreviation) and 0.3g anhydrous magnesium sulfate, add described pedotheque extract to be clean, vortex 2min, with the centrifugal 5min of rotating speed of 9000r/min; After centrifugal, pipette 2.0mL supernatant to scale test tube, under 50～60 ℃ of water-baths, supernatant is slowly blown to 50～70 μ L with nitrogen; In supernatant, add again acetone to be settled to 1.0mL, cross after 0.22 μ m organic system filter membrane, obtain for measuring the pedotheque extraction and cleaning liquid of organophosphorus pesticide;

In above embodiment, instrument and equipment used has: 7890A gas chromatograph, be furnished with flame photometric detector (FPD) (FPD), 7693 automatic samplers and Chemstation chromatographic work station (U.S. Agilent company); KQ-500DE numerical control supersonic instrument (Kunshan Ultrasonic Instruments Co., Ltd.); TG16-WS table model high speed centrifuge (Hunan Xiang Yi Laboratory Instruments development corporation, Ltd.); HSC-24B Nitrogen evaporator (Tianjin Hengao Technology Development Co., Ltd.); K600 type comminutor (German Bo Lang company); VM-10 vortex oscillator (Korea S Daihan Scientific company); SX2-4-10 muffle furnace (Shanghai leap Medical Devices Co., Ltd.); EXCEED-AD-24 type ultrapure water machine (Chengdu Tangshi Kangning Science and Technology Development Co., Ltd).

Medicine used and reagent: DDVP, Rogor, chlopyrifos, parathion-methyl, malathion, fenifrothion, Hostathion, mass concentration is 1000mg/L, is purchased from Inst. of Environment Protection & Scientific Research Monitor, Ministry of Agric; Acetone, HPLC level (Shanghai Chemical Reagent Co., Ltd., Sinopharm Group); N-propyl group ethylenediamine (PSA), 40～60 μ m (U.S. Agela Technologies company); C18, aperture 6nm, granularity 40～60 μ m (U.S. Sepax Technologies company); Acetonitrile, acetic acid, anhydrous sodium acetate, anhydrous magnesium sulfate (620 ℃ of calcination 4h) are analyzes pure (Shanghai Chemical Reagent Co., Ltd., Sinopharm Group); Experimental water is ultrapure water (18.4M Ω).

The preparation of hybrid standard storing solution:

The compound method of organophosphorus pesticide hybrid standard storing solution is: 7 kinds of organophosphorus pesticide standard reserving solution concentration are 1000mg/L, get respectively 1mL and be placed in 5mL volumetric flask, use acetone diluted constant volume, being mixed with concentration is single mark solution of 200mg/L, in-20 ℃ of lucifuge sealings, preserves.Response according to each agricultural chemicals on FPD detecting device, single mark solution DDVP is got 0.5mL, and Rogor, Hostathion are respectively got 2mL, and all the other organophosphorus list mark solution are respectively got 1mL, are placed in 10mL volumetric flask, use acetone constant volume.In 7 kinds of organophosphorus pesticide hybrid standard storing solutions: DDVP concentration is 10mg/L, chlopyrifos, parathion-methyl, fenifrothion, malathion concentration are respectively 20mg/L, and Rogor, Hostathion concentration are respectively 40mg/L.

Above-mentioned agricultural chemicals hybrid standard storing solution is all placed in 4 ℃ of refrigerators and preserves, and during use, with blank matrix extract, is the matrix hybrid standard working fluid that solvent is mixed with respectively debita spissitudo.

The test findings of the present embodiment:

1, the gas chromatography of test agricultural chemicals is separated

Adopt above-mentioned GC conditions to measure the matrix hybrid standard working solution of 7 kinds of organophosphorus pesticides, standard specimen separating effect is better, and peak shape is symmetrical, and baseline stability illustrates that instrument condition is applicable to.Under this chromatographic condition, the retention time of each agricultural chemicals of organophosphorus is about respectively DDVP 5.941min, Rogor 13.099min, chlopyrifos 15.787min, parathion-methyl 15.915min, malathion 16.479min, fenifrothion 16.607min, Hostathion 22.684min is (shown in accompanying drawing 1, in accompanying drawing 1, label 1 is DDVP, concentration is 0.25mg/L, label 2 is Rogor, concentration is 1mg/L, label 3 is chlopyrifos, concentration is 0.5mg/L, label 4 is parathion-methyl, concentration is 0.5mg/L, label 5 is malathion, concentration is 0.5mg/L, label 6 is fenifrothion, concentration is 0.5mg/L, label 7 is Hostathion, concentration is 1mg/L).

2, matrix effect

Matrix effect refers to the impact of the matrix components of other except determinand on determinand measured value in sample.Matrix effect is for the situation of different samples and determinand and difference.In gas chromatographic analysis, most of agricultural chemicals show matrix enhancement effect in various degree, be the agricultural chemicals of the same concentrations response in matrix than it height in neat solvent, the existence of being commonly considered as sample mesostroma composition has reduced the chance of chromatographic system avtive spot and determinand molecular action, and determinand detection signal is strengthened.The method of eliminating matrix effect impact has matrix matching standard solution method, standard addition method, multiple purifying method, analysis protectant application and statistical method correction etc.In the present invention, adopt the ratio of the response of determinand in matrix hybrid standard working solution and neat solvent mixed standard solution to represent matrix effect, ratio more approaches 1, shows that matrix effect is less.

Test findings shows, 7 kinds of agricultural chemical compounds analyzing all exist matrix enhancement effect in various degree, and the matrix effect of 7 kinds of organophosphorus pesticides is all stronger, as shown in Figure 2.So the present invention, when quantitative by external standard method, is solvent preparation standard specimen with blank matrix extract, to eliminate matrix interference, reduces error.(in accompanying drawing 2, label 1 represents the matrix hybrid standard working solution and the neat solvent mixed standard solution that contain DDVP, and concentration is 0.05mg/L; Matrix hybrid standard working solution and the neat solvent mixed standard solution of label 2 for containing Rogor, concentration is 0.2mg/L; In like manner, label 3 represents to contain chlopyrifos, and concentration is 0.1mg/L; Label 4 represents to contain parathion-methyl, and concentration is 0.1mg/L; Label 5 represents to contain malathion, and concentration is 0.1mg/L; Label 6 is fenifrothion, and concentration is 0.1mg/L; Label 7 is Hostathion, and concentration is 0.2mg/L; A _mthe response that represents each agricultural chemicals in matrix matching mixed standard solution; A _sthe response that represents each agricultural chemicals in neat solvent mixed standard solution).

3, the range of linearity of method, regression equation and detection limit

7 kinds of organophosphorus pesticide matrix mixed standard solutions that preparation mass concentration is 0.01～4.0mg/L, by the chromatographic condition of the organophosphorus pesticide in the 3rd step of described first, measure respectively, with mass concentration, (with ρ, represent, unit is mg/L) be horizontal ordinate, take peak area (y) as ordinate drawing standard curve, 7 kinds of agricultural chemicals are good in its concentration range internal linear, related coefficient (r ²) be all greater than 0.996, be shown in Table 1.Respectively with 3 times of noise signal in minimum interpolation horizontal chromatography figure and 10 times of detection limit (LOD) and quantitative limit (LOQ) of calculating each agricultural chemicals.As calculated, the LOD of 7 kinds of organophosphorus pesticides is between 0.0038～0.022mg/kg, and LOQ is between 0.013～0.072mg/kg, referring to below shown in table 1.

Table 1 is for the range of linearity, regression equation, related coefficient, detection limit and the quantitative limit of examination agricultural chemicals

4, the recovery of method and precision

Adopt blank sample mark-on method to carry out the method recovery and precision mensuration.Take 5.0g after measured not containing some parts of the blank pedotheque for examination agricultural chemicals, the agricultural chemicals hybrid standard working fluid that adds respectively 3 kinds of variable concentrations levels, the interpolation level of organophosphorus pesticide is 0.025～1.0mg/kg, parallel 3 duplicate samples of each concentration level, after vortex mixes, standing 1h makes standard solution fully be absorbed by sample, according to described second portion, carries out sample pre-treatments and chromatographic condition mensuration.Adopt matrix external standard method quantitative, calculate average recovery rate and the relative standard deviation (being RSD) thereof of each agricultural chemicals, ginseng is shown in Table 2, and sample mark-on chromatogram is referring to accompanying drawing 3.

As shown in Table 2, in soil, the average recovery rate of organophosphorus pesticide is that 73.9%～96.6%, RSD (n=3) is 1.3%～9.4%, and illustration method has good accuracy and repeatability.

Table 214 kind reclaims result (n=3) for trying the interpolation of agricultural chemicals in soil

Wherein, in accompanying drawing 3, label 1 is DDVP, and concentration is 0.25mg/L, label 2 is Rogor, and concentration is 1mg/L, and label 3 is chlopyrifos, concentration is 0.5mg/L, and label 4 is parathion-methyl, and concentration is 0.5mg/L, label 5 is malathion, concentration is 0.5mg/L, and label 6 is fenifrothion, and concentration is 0.5mg/L, label 7 is Hostathion, and concentration is 1mg/L.

5, actual sample analysis

Adopt this method to the pedotheque of taking from local certain tea plantation in Suzhou totally 16 parts carried out 7 kinds of organophosphorus pesticides and detected, do not detect organophosphorus insecticide.Result of study shows, this method can be used for the detection of 7 kinds of organophosphorus pesticides in soil.

Above-described embodiment is only explanation technical conceive of the present invention and feature, and its object is to allow person skilled in the art can understand content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalences that Spirit Essence is done according to the present invention change or modify, within all should being encompassed in protection scope of the present invention.

Claims

1. a quantitative detecting method for organophosphorus insecticide in soil, is characterized in that: described quantitative detecting method is comprised of two parts:

(1) take 5.0 g after measured not containing the blank pedotheque of tested organophosphorus pesticide in 50 mL centrifuge tubes, in centrifuge tube, add 2 mL ultrapure waters again, vortex mixes, and infiltrates 10～20min, then to add 10 mL be the acetonitrile solution of 1% acetic acid containing volume fraction, mix, ultrasonic extraction 10～15 min, add 2 g anhydrous sodium acetates and 2 g anhydrous magnesium sulfates, vortex 2 min, with the centrifugal 4min of 9000 r/min rotating speed, get supernatant and be blank matrix extract to be clean;

(2) separately get 10 mL centrifuge tubes, add 0.15g C18,0.15g N-propyl group ethylenediamine and 0.3g anhydrous magnesium sulfate, add blank matrix extract to be clean described in 4mL, vortex 1.5min ~ 2.5min, with the centrifugal 4.5min ~ 5.5min of rotating speed of 9000 r/min; After centrifugal, pipette 2.0 mL supernatants to scale test tube, then under 50～60 ℃ of water-baths, supernatant is slowly blown to 50 ~ 70 μ L with nitrogen; In supernatant, add again acetone to be settled to 1.0mL, cross after organic system filter membrane, obtain for preparing the blank matrix extract of organophosphorus pesticide;

Chromatographic column: the capillary chromatographic column that model is DB-1701, specification is 30m * 0.32mm * 0.25 μ m; Sample size: 1.0 μ L, Splitless injecting samples; Injector temperature: 220 ℃, dottle pin purges 3mL/min; Column temperature: 90 ℃ of initial temperatures, keep 1min, 20 ℃/min rises to 200 ℃, keeps 9min, and 30 ℃/min rises to 245 ℃, keeps 8min; Carrier gas: high pure nitrogen, purity >=99.999%; Constant current mode, flow velocity 3mL/min; Detecting device: flame photometric detector (FPD); Detector temperature: 245 ℃; Hydrogen: flow is 75 mL/min; Air: flow is 100 mL/min; Make-up gas: high pure nitrogen, flow is 60mL/min;

The first step, extracts pedotheque;

Take the pedotheque of having pulverized, be placed in 50 mL centrifuge tubes, then to add containing volume fraction be the acetonitrile solution of 1% acetic acid, wherein, the input ratio of described pedotheque and described acetonitrile solution, for to dropping into acetonitrile solution described in 1mL in every 0.5g pedotheque, mixes ultrasonic extraction 10～15 min; Add again anhydrous sodium acetate and anhydrous magnesium sulfate, wherein, described pedotheque, anhydrous sodium acetate and anhydrous magnesium sulfate three's mass ratio is 5:2:2, vortex 1.5min ~ 2.5min, with the centrifugal 3.5min ~ 4.5min of rotating speed of 9000 r/min, get supernatant and be pedotheque extract to be clean;

Second step, purifies described pedotheque extract to be clean;

Separately get 10 mL centrifuge tubes, add C18, N-propyl group ethylenediamine and anhydrous magnesium sulfate, add described pedotheque extract to be clean, wherein, the content of C18, N-propyl group ethylenediamine and the anhydrous magnesium sulfate dropping in pedotheque extract to be clean is respectively 37.5mg/mL, 37.5mg/mL and 75mg/mL, vortex 1.5min ~ 2.5min, with the centrifugal 4.5min ~ 5.5min of rotating speed of 9000 r/min; After centrifugal, pipette 1.5 mL supernatants to scale test tube, under 50～60 ℃ of water-baths, supernatant is slowly blown to 50 ~ 70 μ L with nitrogen; In supernatant, add again acetone to be settled to 0. 75 mL, cross after organic system filter membrane, obtain for measuring the pedotheque extraction and cleaning liquid of organophosphorus pesticide;

2. the quantitative detecting method of organophosphorus insecticide in a kind of soil according to claim 1, it is characterized in that: in the first step of described first and the first step of described second portion the condition of ultrasonic extraction be ultrasonic power between 80W ~ 100W, ultrasonic temperature is at 20～30 ℃.