The detection method of organo-chlorine pesticide in a kind of sedimentary column core
Technical field
The present invention relates to Organochlorine Pesticide Residues detection technique fields, and in particular to organo-chlorine pesticide in a kind of sedimentary column core
Detection method.
Background technique
Organo-chlorine pesticide (OCPS) it is organic containing organic chlorine element in the constituent of plant pest for preventing and treating
Compound has played great effect in human production life, but its bio-toxicity and characteristic difficult to degrade make it
As a kind of serious environmental contaminants.The hydrophobic lipophilic characteristic of organic pollutant makes their contents in water body lower,
It is most of to be adsorbed by the suspended particulate matter in water body such as mineral, bioclast and colloidal substance, and with gravitational settling etc.
Physics chemical action enters in water body deposit or is enriched in organism by bio-absorbable.Therefore water body deposit is environment dirt
The final storage place of object is contaminated, the pollutant in deposit plays an important role to the living environment of aqueous bio, in order to study
The Historical Evolution rule of pollutant, needs to carry out the deposit of water-bed different depth sampling and quantitative analysis in deposit.
In detecting sedimentary column core when the concentration of pollutant, the standard generallyd use in GB/T14550-2003 is examined
It surveys.However, early period does not seek unity of standard to the preprocess method of sedimentary column core in entire characterization processes flowchart process, thus
Cause organo-chlorine pesticide in sedimentary column core to extract to be not enough, to cause that organo-chlorine pesticide detection error is larger, accuracy rate
It substantially reduces.Therefore, it needs to design a kind of new technical solution, solves problems of the prior art with comprehensive.
Summary of the invention
The object of the present invention is to provide a kind of detection methods of organo-chlorine pesticide in sedimentary column core, can effectively solve existing
The problem of preprocess method present in technology is nonstandard, accuracy rate larger so as to cause organo-chlorine pesticide detection error reduces.
In order to solve the above technical problems, the invention adopts the following technical scheme:
The detection method of organo-chlorine pesticide in a kind of sedimentary column core, comprising the following steps:
Step 1: sample acquires: carrying out vertical sampling using polyethylene pipe, after loam core is left the water, scene uses plunger tip
Device ejects loam core bottom-up;
Step 2: cutting process: cutter cuts loam core is used by the interval 1.0cm, then by the good rear loam core sample of segmentation
It is directly placed into polymeric seal bag and numbers, later freezen protective under the conditions of -20 DEG C;
Step 3: freeze-drying: being freeze-dried under the conditions of loam core sample is placed in -30 DEG C, until moisture in loam core sample
Until removal;
Step 4: it grinds sieving: rejecting the impurity after being freeze-dried in loam core sample, crushed 200 meshes later;
Step 5: depositional age calculates: after the loam core samples weighing of different numbers, being transferred to closed centrifuge tube, seal
Examination with computer is carried out after standing 3 weeks or more, test loam core sample210Pb, 46.5KeV;226Ra, 352KeV;137Cs, 662Kev,
It distinguishes the loam core sample in different sedimentary column core ages and numbers label;
Wherein the calculation formula of sedimentary column core age and deposition rate is as follows:
T=ln [I (s)/I (m)]/λ
V=λ I (m)/A (m)
T is sedimentation time in formula, and I (s) is in sedimentary column210PbexTotal amount, I (m) are under m meters of depth210PbexTotal amount, v are
Deposition rate, A (m) are in m deep layer210PbexActive total amount, λ are represented210Decay coefficient λ=0.031yr of Pb-1, wherein210Pbex=total210Pb-226Ra;
Step 6: extracting: weighing the loam core sample n-hexane-acetone extraction solvent in different sedimentary column core ages in 42-
44 DEG C are stripped 48h with copper sheet, collect extract later;
Step 7: purification: after concentrated by rotary evaporator by extract, being carried out using peroxidating aluminium/silica gel column chromatography net
Change, reuses methylene chloride/n-hexane mixed liquor later and elute the component containing organo-chlorine pesticide, most afterwards through nitrogen evaporator
Further it is concentrated;
Step 8: test: above-mentioned concentrate being carried out the makings that gas chromatograph and mass spectrograph are used in conjunction and is analyzed, and mode is
Analysis result can be obtained in choice ion pattern, analysis.
Further scheme is that the internal diameter of polyethylene pipe is 9-11cm in step 1.
Further scheme is that extraction steps are carried out using Soxhlet extractor, weighs 25g loam core sample in juxtaposition in filter paper
In in the extraction tube of Soxhlet extractor, 250mL n-hexane-acetone extraction solvent and 2g copper are added in the extraction flask of Soxhlet extractor
Piece.
Further scheme is that the volume ratio of peroxidating aluminium and silica gel is in peroxidating aluminium/silica gel column chromatography in step 5
1:2, the volume ratio of methylene chloride and n-hexane is 3:7 in methylene chloride/n-hexane mixed liquor.
Further scheme is that the chromatographic column that gas chromatograph separation uses in step 6 is TR-5MS capillary column,
With 30m × 0.25mm × 0.25 μm high-resolution, carrier gas is helium (99.999%), and flow velocity 1mL/min, temperature programming is such as
Under: initial temperature is 50 DEG C, keeps 2min;With 20 DEG C of min-1Rate be raised to 180 DEG C of holding 3min;Then with 8 DEG C of min-1's
Rate is raised to 250 DEG C, keeps 3min;Again with 2 DEG C of min-1Rate be raised to 265 DEG C, then with 5 DEG C of min-1Rate be raised to
275 DEG C, finally with 1 DEG C of min-1Rate be raised to 285 DEG C.
The detection method of organo-chlorine pesticide in the sedimentary column core provided in above-mentioned technical proposal, to the loam core sample of acquisition into
Row cutting process obtains segmentation sample, to obtain the sample in different sedimentary column core ages;In addition sample to be detected is carried out
Pretreatment is ground, dries moisture removal, is obtained drying sample, and keep drying to the subsequent container for containing sample, is guaranteed
Sample drying, and then keep testing result more accurate;Soxhlet extraction is finally used, n-hexane-acetone extraction solvent is added, continuously
48h is extracted, the adequacy that organo-chlorine pesticide is dissolved can be effectively improved, to improve the accuracy of final detection result.
Detailed description of the invention
Fig. 1 is the flow chart of the detection method of organo-chlorine pesticide in sedimentary column core of the present invention;
Fig. 2 is the chromatogram of organo-chlorine pesticide in sedimentary column core of the present invention;
Fig. 3 is sedimentary column core of the present invention210PbexActivity and depth section relational graph.
Specific embodiment
In order to which objects and advantages of the present invention are more clearly understood, the present invention is carried out specifically with reference to embodiments
It is bright.It should be appreciated that following text is only used to describe one or more of specific embodiments of the invention, not to the present invention
The protection scope specifically requested carries out considered critical.
Technical solution that the present embodiment is taken as shown in Figure 1, in a kind of sedimentary column core organo-chlorine pesticide detection method, packet
Include following steps:
Step 1: sample acquires: vertical sampling is carried out using the polyethylene pipe that diameter is 10cm, to ensure depositional sequence not
By sampler disturbance and destroyed, sampler is vertical and gently disposably takes the complete loam core in seabed, complete mud as far as possible
After core is left the water, scene is ejected loam core using bottom plunger tip device bottom-up.
Step 2: cutting process: cutter cuts loam core is used by the interval 1.0cm, then by the good rear loam core sample of segmentation
It is directly placed into polymeric seal bag and number 1-40, later freezen protective under the conditions of -20 DEG C.
Step 3: freeze-drying: being freeze-dried under the conditions of loam core sample is placed in -30 DEG C, until moisture in loam core sample
Until removal.
Step 4: it grinds sieving: rejecting the impurity after being freeze-dried in loam core sample, crushed 200 meshes later.
Step 5: depositional age calculates: after the loam core samples weighing of different numbers (1-40), being transferred to closed centrifugation
Pipe carries out examination with computer (the instrument title used in the present embodiment are as follows: Ortec HPGe GWL gamma after sealing and standing 4 weeks
Spectrometry), loam core sample is tested210Pb, 46.5KeV;226Ra, 352KeV;137Cs, 662Kev distinguish not synsedimentary
The loam core sample in column core age simultaneously numbers label;
Depositional age calculation method: a constant rate of supply (CRS) model (constant recharge rate mould
Formula), wherein the calculation formula of sedimentary column core age and deposition rate is as follows:
T=ln [I (s)/I (m)]/λ
V=λ I (m)/A (m)
T is sedimentation time in formula, and I (s) is in sedimentary column210PbexTotal amount, I (m) are under m meters of depth210PbexTotal amount, v are
Deposition rate, A (m) are in m deep layer210PbexActive total amount, λ are represented210Decay coefficient λ=0.031yr of Pb-1;Each sample
Supported in product210Pb (compensation210Pb activity) assume and226Ra (parent226Ra it) balances, in this way210PbexIt is (superfluous210Pb)=total210Pb-226Ra;Fig. 3 is sedimentary column core210PbexActivity and depth section relational graph, it is available according to Fig. 3
The sedimentation time of different loam core samples.
Step 6: extracting: taking disposable polyethylene Thin film glove, will be converted into advance with the filter paper that methylene chloride extracted
Cylindrical shape, cylindrical filter paper one end is pressed obturage with tweezers, is weighed loam core sample 25g on an electronic balance and is packed into cylindrical filter paper
It is interior then another end closure of cylindrical filter paper is tight, it is put into the extraction tube of Soxhlet extractor, is added in by extraction flask
The n-hexane of 250mL-acetone extraction solvent and 2g copper sheet, Soxhlet extractor top connect condenser pipe, use tin above condenser pipe
Foil lid is lived;Later Soxhlet extraction system being put into heat on water-bath and be extracted, temperature is controlled at 42-44 DEG C, in extractive process,
Solvent instills Soxhlet extractor with the rate of 2-4mL/min on condenser pipe, extracts 48h, collects extract;Water-bath is closed, it is cold
But it after, slowly pours extract remaining in soxhlet type container into extraction flask, removes extraction flask, cover grinding port plug and wrap sealing
To prevent from volatilizing, number saves film.
Step 7: purification: (using n-hexane as conversion solvent) is concentrated through Rotary Evaporators in extract, uses peroxidating
Aluminium/silica gel (volume ratio of peroxidating aluminium and silica gel be 1:2) chromatographic column is purified, and reuses 70mL methylene chloride/just later
Hexane (volume ratio of methylene chloride and n-hexane is 3:7) mixed liquor elutes the component containing organo-chlorine pesticide, finally
It is further concentrated through nitrogen evaporator.
Step 8: test: above-mentioned concentrate is carried out Thermo Trace Ultra gas chromatograph and Thermo DSQ
The makings analysis that II mass spectrograph is used in conjunction, mode is choice ion pattern, and separatory chromatographic column is TR-5MS capillary column, and is had
Have 30m × 0.25mm × 0.25 μm high-resolution, carrier gas is that constant current speed is that temperature programming is as follows: initial temperature is 50 DEG C, is protected
Hold 2min;With 20 DEG C of min-1Rate be raised to 180 DEG C of holding 3min;Then with 8 DEG C of min-1Rate be raised to 250 DEG C, keep
3min;Again with 2 DEG C of min-1Rate be raised to 265 DEG C, then with 5 DEG C of min-1Rate be raised to 275 DEG C, finally with 1 DEG C of min-1
Rate be raised to 285 DEG C.
Organo-chlorine pesticide chromatogram as shown in Figure 2 is finally obtained, wherein retention time is 0-40.7, according to different organic
The retention time of chloro pesticide is different, qualitative to the progress of variety classes organo-chlorine pesticide successive peak sequence, and determination is not of the same race organic
Chloro pesticide.
4 25g loam core samples of every analysis do following quality control: 1 plus matrix (four chloro-m-xylenes) sample detection reality
The reliability of proved recipe method;Whether extraneous factor has interference during 1 blank sample test experience;3 parallel sample detections are real
The error of proved recipe method.
The above results are as follows: the rate of recovery for adding matrix (four chloro-m-xylenes) sample is 91.6%-101%;Blank sample
In the presence of target substance is not detected;The relative standard deviation range of parallel sample is 0.1%-4.0%, and all quality are protected
Card and quality control are in acceptable range.
Therefore using the detection method of organo-chlorine pesticide in sedimentary column core of the present invention, first the cylindrical sample of acquisition is cut
Processing is cut, the segmentation sample of various years is obtained;Segmentation sample is ground later, dries moisture removal, obtains drying sample, it
N-hexane-acetone extraction solvent is added using Soxhlet extraction afterwards;Organo-chlorine pesticide can be effectively improved using the above method to be dissolved
Adequacy, and then improve the accuracy that finally detects, reduce error.
Embodiments of the present invention are explained in detail above in conjunction with attached drawing, but the present invention is not limited to above-mentioned implementations
Mode in knowing the present invention after contents, is not departing from the present invention for those skilled in the art
Under the premise of principle, several same transformation and substitution can also be made to it, these convert and substitute on an equal basis and also should be regarded as belonging to
Protection scope of the present invention.