CN105486791A - Fe3O4@SiO2@G magnetic adsorbent and method for detecting 16 anti-staling agents in vegetable by using same - Google Patents

Abstract

The invention discloses a Fe3O4@SiO2@G magnetic adsorbent and a method for detecting 16 anti-staling agents in vegetable by using the same. Compared with a conventional filling material of a solid-phase extraction column, the Fe3O4@SiO2@G magnetic adsorbent provided by the invention has a larger specific surface area and shorter diffusion distance and can realize extraction and separation under the conditions of a small application amount and short equilibrium time, so the Fe3O4@SiO2@G magnetic adsorbent provided by the invention has higher extraction capability and extraction efficiency. The Fe3O4@SiO2@G magnetic adsorbent prepared in the invention is used for removing impurities and can simultaneously determine 16 anti-staling agents including mythyl-p-hydroxybenzoate, ethyl-p-hydroxybenzoate, propyl-p-hydroxybenzoate, butyl-p-hydroxybenzoate, biphenyl ether, ethyl naphthol, p-phenylphenol, pyrimethanil, chlopyrifos, triadimefon, procymidone, imazalil, myclobutanil, flusilazole, propiconazole and prochloraz. Results show that the Fe3O4@SiO2@G magnetic adsorbent has good impurity removing effect and shows good recovery rate and precision to the 16 anti-staling agents.

Description

A kind of Fe 3o 4siO 2g magnetic adsorbent and the method for detecting 16 kinds of antistaling agents in vegetables thereof

Technical field

The invention belongs to chemical analysis detection field, specifically a kind of Fe ₃o ₄siO ₂the preparation of G Magnetic solid phases adsorbent and measure with GC-MS the method that in vegetables, 16 kinds of antistaling agents are residual on this solid-phase adsorbent basis.

Background technology

Vegetables are indispensable in people's diet, because it contains abundant vitamin and mineral matter.But the fresh keeping time of vegetables is short, is unfavorable for transport and stores.Therefore, usually add antistaling agent to go bad to prevent vegetable spoilage.Because chemical preservative has low price, the advantages such as easy grasp, are widely used in the fresh-keeping of vegetables.But a large amount of uses of chemical preservative cause it residually to exceed standard, and serious harm consumer's is healthy, even may cause cancer and some nervous system, genital system diseases.Many countries pay much attention to the residual problem of antistaling agent, and have carried out strict restriction to agricultural products fresh-keeping agent residual quantity.When food security is day by day concerned, along with the raising of detection technique, Sample Pretreatment Technique will improve further, seeks the more effective removal of impurities adsorbent of one and seems particularly important to improve purification rate.

Magnetic solid phases extraction (MSPE) is a kind of novel sample pretreatment that developed recently gets up.MSPE can realize being separated by means of only applying external magnetic field, simple to operate, save time fast, without the need to troublesome operation such as centrifugal filtrations.Compared with traditional Solid-Phase Extraction (SPE) adsorbent, the magnetic adsorbent of MSPE can be separated easily under the effect of externally-applied magnetic field, and does not need extra centrifugal or filter.It has simple to operate, quick, bioaccumulation efficiency is high, the advantage such as environmentally friendly, avoid traditional SPE adsorbent and need fill the time consuming procedures found such as post and bulk sample loading, and the problem of the column jecket blocking often occurred in SPE can be avoided when processing biology, environmental sample.Graphene (G) be a kind of by carbon atom with sp ²hybrid orbital composition hexangle type is the flat film of honeycomb lattice, has the specific surface area of super large, large conjugated system, very strong hydrophobicity, higher acidproof, alkaline-resisting, heat resistance and chemical stability.Strong π-pi-electron can be produced with organic molecule to interact.Fe ₃o ₄magnetic Nano material specific surface area is large, diffusion length is short, can realize being separated, can also recycle after suitable rinse by applying an external magnetic field.Therefore magnetic graphene nano composite material (Fe ₃o ₄siO ₂g) can as the sorbent material of MSPE function admirable.

Given this, the object of this invention is to provide a kind of Fe ₃o ₄siO ₂g magnetic adsorbent and this magnetic adsorbent is used for the detection method simultaneously detecting 16 antistaling agents in vegetables.

In order to realize above-mentioned first object the technical solution used in the present invention be: a kind of Fe prepared by following methods ₃o ₄siO ₂g magnetic adsorbent:

(1) by GO ultrasonic dissolution in 50mLN, dinethylformamide (DMF).

(2) join in the solution of step (1) by 0.1gN-hydroxysuccinimide (NHS) and 0.2g1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), 25 DEG C are stirred 2h.

(3) by Fe ₃o ₄siO ₂-NH ₂join in the solution of step (2), 25 DEG C of stirrings are spent the night, and the condition of product outside magnetic field is separated with dispersion liquid, after water cleaning 2-3 time, air-dry, obtain Fe ₃o ₄siO ₂g magnetic adsorbent.

Step (1) described GO and step (3) Fe ₃o ₄siO ₂-NH ₂consumption, GO and Fe ₃o ₄siO ₂-NH ₂the part by weight that adds be 1:9 to 3:7.In the present invention, different ratio synthesis Fe is adopted ₃o ₄siO ₂gO, after being carried out reduction reaction, by the Fe of often kind of synthesis ratio ₃o ₄siO ₂g Magnetic solid phases adsorbent is respectively used to the purification process of vegetable sample simultaneously.Result shows that synthesis ratio is that 3:7 is best.To the Fe of final synthesis ₃o ₄siO ₂g Magnetic solid phases adsorbent carries out SEM scanning (Fig. 1), can see that particle is subsphaeroidal, and surface has Graphene thin layer to wrap up.

In order to realize above-mentioned second object, the invention provides a kind of above-mentioned magnetic adsorbent and detecting the application in vegetables in 16 kinds of antistaling agents.Concrete grammar is as follows:

(1) extract

With stirring machine by after homogeneous for appropriate vegetables, take the homogenate of 10.0g vegetables in 50mL centrifuge tube, add 20mL acetonitrile and 4mL ammonium acetate solution (2mol/L), vortex mixing 2min, horizontal oscillations 10min, then add 5.0g sodium chloride in centrifuge tube, vortex mixing 1min again, the centrifugal 3min of 5000r/min, Aspirate supernatant I is in centrifuge tube, to be clean.

(2) sample is purified

By 100mgFe ₃o ₄siO ₂be equipped with in the centrifuge tube of supernatant I described in G and 500mg anhydrous magnesium sulfate adds, vortex mixing 3min, is separated mixed liquor with externally-applied magnetic field, and Aspirate supernatant II steams in bottle in revolving.

(3) concentrated

Steam the water-bath rotary evaporation that bottle is placed in less than 40 DEG C be concentrated into clean dry by revolving, add 1mL acetone, vortex oscillation revolves object in steaming bottle to dissolve, and after membrane filtration, detects for GC-MS.

(4) GC-MS measures, and condition determination is as follows:

Each Compound Retention time and mass spectrometry parameters, in table 1, are wherein with * to represent quota ion;

Chromatographic column: DB-5MS quartz capillary column, 30m × 0.25mm × 0.25 μm;

Column temperature program: initial temperature 70 DEG C, keeps 2min, then rises to 280 DEG C with 10 DEG C/min, keeps 5min;

Flow velocity: 1.2mL/min;

Ion gun: EI source, ionizing energy 70eV;

Ion source temperature: 230 DEG C;

Level Four bar temperature: 150 DEG C;

Interface temperature: 280 DEG C;

Solvent delay: 5min;

Sample size: 1 μ L; Splitless injecting samples;

Injector temperature: 250 DEG C;

Total run time: 28min;

The reference retention time of table 116 kind of antistaling agent and mass spectrometry parameters

Extract in the process of antistaling agent by organic phase, the impurity of some interference also can be extracted, and these impurity can produce the ionization process of measured object in mass detector and suppress, and make its sensitivity decrease.The graphene nanocomposite material of this method synthesis is for removing impurity better effects if, and than using, solid phase extraction column saves time conveniently more, price is cheaper.In the present invention by the chromatogram of blank sample with add Fe ₃o ₄siO ₂the chromatogram of the sample after the purification of G is overlapping, and result shows Fe ₃o ₄siO ₂g has good adsorption effect to impurity such as beta naphthal, 2-quinoline methanol and nipecotic acids.

The present invention uses acetonitrile as Extraction solvent, extracts 16 kinds of antistaling agents in vegetables.The magnetic adsorbent adopting the present invention to prepare carries out fast purification, compared with traditional solid phase extraction adsorbents, can realize being separated, without the need to steps such as centrifugal filtrations by means of only applying externally-applied magnetic field, operation is more simple, quick, effectively can shorten the time of purification.Test period when adopting prior art to detect is usually at more than 45min, and the present invention only needs 35min.Detect while present invention achieves multiple antistaling agent, establish the residual method that magnetic adsorbent purification-GC-MS measures 16 kinds of antistaling agents in vegetables.

Accompanying drawing explanation

Fig. 1: Magnetic solid phases adsorbent Fe prepared by the present invention ₃o ₄siO ₂scanning electron microscope (SEM) figure of G;

The GC-MS collection of illustrative plates (0.25mg/L) of Fig. 2: ten six kinds of antistaling agent standard solution, in figure, horizontal ordinate represents each antistaling agent retention time, and ordinate represents the response intensity of each antistaling agent;

A-Biphenyl Ether, B-methyl p-hydroxybenzoate, C-ethyl naphthol, D-ethyl p-hydroxybenzoate, E-P-hydroxybenzoic acid third fat, F-p-phenyl phenol, G-parahydroxybenzoate butyl, the phonetic mould amine of H-, I-chlopyrifos, J-triazolone, K-procymidone, L-imazalil, M-nitrile bacterium azoles, N-Flusilazole, O-propiconazole, P-prochloraz.

Embodiment

Below in conjunction with embodiment, the specific embodiment of the present invention is further described.Following examples for illustration of the present invention, but are not used for limiting the scope of the invention.

One, the preparation of magnetic graphene nano particle adsorbent of the present invention

Embodiment 1, (1) prepares magnetic Fe ₃o ₄nano particle

Accurately take 3.40g six aqueous ferrous sulfate ammonium and 8.35g ten sulfate dihydrate iron joins in the water of 400mL50 DEG C, then the ammoniacal liquor dripping 20mL is with iron oxide precipitation, ultrasonic 10min, is adjusted to 11 by pH value.This mixed solution stirs 1h, is precipitated thing.Be 7 by sediment undergoes washing to pH value with distilled water, the precipitation of acquisition be dispersed in water, 1.7mL polyvinylpyrrolidone (PVP) is joined in potpourri, at room temperature stir 1 day, obtain Fe ₃o ₄nano particle.

(2) Fe is prepared ₃o ₄siO ₂

1.4gFe ₃o ₄microballoon be poured in the mixed solution containing 280mL ethanol and 70mL water, add the ammoniacal liquor of 5mL.After stirring 15min, drip the ethyl orthosilicate (TEOS) of 4mL.Stir 8h at ambient temperature, product external magnetic field is separated, and uses ethanol purge.The Fe of gained ₃o ₄siO ₂be dispersed in isopropyl alcohol.

(3) Fe is prepared ₃o ₄siO ₂-NH ₂

The 3-aminopropyl triethoxysilane solution (APTES) of 0.2mL is added drop-wise to above-mentioned 40mLFe ₃o ₄siO ₂in solution, the isopropanol of 100mL.After ultrasonic 30min, Keep agitation 6h, product is cleaned respectively by water and ethanol, dry under vacuum conditions.

(4) Fe is prepared ₃o ₄siO ₂-GO

The GO of 0.2g is dissolved in the N of 50mL under ultrasound condition, in dinethylformamide (DMF), then 0.1gN-hydroxysuccinimide (NHS) and 0.2g1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) join in dispersion liquid, stir 2h at ambient temperature.Then the Fe of 0.5g is added ₃o ₄siO ₂-NH ₂.Stir at ambient temperature and spend the night, after products in water cleaning, air-dry.

(5) Fe is prepared ₃o ₄siO ₂g

0.2gFe ₃o ₄siO ₂-GO is dissolved in 100mL water, adds 200uL hydrazine hydrate, after stirring 2h.Products in water cleaning 2-3 time, drying under 80 DEG C of conditions is also preserved.

Embodiment 2, each process is all carried out according to embodiment 1, only changes the consumption of GO in step (4) into 0.00g, Fe ₃o ₄siO ₂-NH ₂consumption change 0.70g into.

Embodiment 3, each process is all carried out according to embodiment 1, only changes the consumption of GO in step (4) into 0.07g, Fe ₃o ₄siO ₂-NH ₂consumption change 0.63g into.

Embodiment 4, each process is all carried out according to embodiment 1, only changes the consumption of GO in step (4) into 0.35g, Fe ₃o ₄siO ₂-NH ₂consumption change 0.35g into.

Embodiment 5, each process is all carried out according to embodiment 1, only changes the consumption of GO in step (4) into 0.3g, Fe ₃o ₄siO ₂-NH ₂consumption change 0.7g into.

Two, magnetic adsorbent purification-GC-MS

(1) extract

With stirring machine by after homogeneous for appropriate vegetables, take the homogenate of 10.0g vegetables in 50mL centrifuge tube, add 20mL acetonitrile and 4mL ammonium acetate solution (2mol/L), vortex mixing 2min, horizontal oscillations 10min, then add 5.0g sodium chloride in centrifuge tube, vortex mixing 1min again, the centrifugal 3min of 5000r/min, Aspirate supernatant I is in centrifuge tube, to be clean.

(2) sample is purified

By 100mgFe ₃o ₄siO ₂be equipped with in the centrifuge tube of supernatant I described in G and 500mg anhydrous magnesium sulfate adds, vortex mixing 3min, is separated mixed liquor with externally-applied magnetic field, and Aspirate supernatant II steams in bottle in revolving.

(3) concentrated

Steam the water-bath rotary evaporation that bottle is placed in less than 40 DEG C be concentrated into clean dry by revolving, add 1mL acetone, vortex oscillation revolves object in steaming bottle to dissolve, and after membrane filtration, detects for GC-MS.

(4) GC-MS measures, and condition determination is as follows:

Chromatographic column: DB-5MS quartz capillary column, 30m × 0.25mm × 0.25 μm;

Column temperature program: initial temperature 70 DEG C, keeps 2min, then rises to 280 DEG C with 10 DEG C/min, keeps 5min;

Flow velocity: 1.2mL/min;

Ion gun: EI source, ionizing energy 70eV;

Ion source temperature: 230 DEG C;

Level Four bar temperature: 150 DEG C;

Interface temperature: 280 DEG C;

Solvent delay: 5min;

Sample size: 1 μ L; Splitless injecting samples;

Injector temperature: 250 DEG C;

Total run time: 28min;

Each Compound Retention time: in table 1;

Mass spectrometry parameters: in table 1;

(5) result calculates

With chromatographic data processor or the content pressing antistaling agent in formula (1) calculating sample, result of calculation must deduct blank value;

$X_i=\frac{C_i\×V\×1000}{m\×1000}---\left(1\right)$

In formula:

X _i---the content of test substance in sample to be tested, unit is milligrams per kilogram;

C _i---from the solution concentration of the test substance that GC-MS spectrogram obtains, unit is milligrams per liter;

V---the final constant volume of sample liquid, unit is milliliter;

M---final sample to be tested quality representated by sample liquid, unit is gram.

The present invention carries out interpolation recovery test to cabbage at the antistaling agent of 0.01mg/kg, 0.02mg/kg, 0.05mg/kg tri-variable concentrations levels, and the average recovery rate that replicate determination is 6 times and relative standard deviation are in table 2.

Table 2 mark-on average recovery rate and relative standard deviation

Note: the sequence number detecting thing in table is consistent with the detection thing sequence number in table 1

As can be seen from above example, the embodiment of the present invention is purified by the adsorbent of solvent extraction, preparation, concentrate etc. is detected antistaling agent multiple in export vegetable, and method has higher sensitivity, accuracy and precision.

Claims (4)

1. a Fe ₃o ₄siO ₂g magnetic adsorbent, is characterized in that being prepared by following methods:

(1) by GO ultrasonic dissolution in 50mLN, dinethylformamide;

(2) by 0.1gN-hydroxysuccinimide with 0.2g1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride joins in the solution of step (1), 25 DEG C are stirred 2h;

(3) by Fe ₃o ₄siO ₂-NH ₂join in the solution of step (2), 25 DEG C of stirrings are spent the night, and the condition of product outside magnetic field is separated with dispersion liquid, after water cleaning 2-3 time, air-dry, obtain Fe ₃o ₄siO ₂g magnetic adsorbent.

2. a kind of Fe according to claim 1 ₃o ₄siO ₂g magnetic adsorbent, is characterized in that: described GO and Fe ₃o ₄siO ₂-NH ₂the part by weight that adds be 1:9 to 3:7.

3. a kind of Fe according to claim 2 ₃o ₄siO ₂g magnetic adsorbent, is characterized in that: described GO and Fe ₃o ₄siO ₂-NH ₂the part by weight that adds be 3:7.

4. utilize Fe described in claim 1-3 ₃o ₄siO ₂g magnetic adsorbent detects the method for 16 kinds of antistaling agents in vegetables, comprises the steps:

(A) extract

Take the homogenate of 10.0g vegetables in 50mL centrifuge tube, add 20mL acetonitrile and 4mL2mol/L ammonium acetate solution, vortex mixing 2min, horizontal oscillations 10min, add 5.0g sodium chloride again in centrifuge tube, again the centrifugal 3min of vortex mixing 1min, 5000r/min, Aspirate supernatant I is in centrifuge tube, to be clean;

(B) sample is purified

By 100mgFe ₃o ₄siO ₂be equipped with in the centrifuge tube of supernatant I described in G and 500mg anhydrous magnesium sulfate adds, vortex mixing 3min, is separated mixed liquor with externally-applied magnetic field, and Aspirate supernatant II steams in bottle in revolving;

(C) concentrated

Steam the water-bath rotary evaporation that bottle is placed in less than 40 DEG C be concentrated into clean dry by revolving, add 1mL acetone, vortex oscillation revolves object in steaming bottle to dissolve, and after membrane filtration, detects for GC-MS;

(D) GC-MS measures, and condition determination is as follows:

Each Compound Retention time and mass spectrometry parameters see the following form, and are wherein with * to represent quota ion;

Chromatographic column: DB-5MS quartz capillary column, 30m × 0.25mm × 0.25 μm;

Column temperature program: initial temperature 70 DEG C, keeps 2min, then rises to 280 DEG C with 10 DEG C/min, keeps 5min;

Flow velocity: 1.2mL/min;

Ion gun: EI source, ionizing energy 70eV;

Ion source temperature: 230 DEG C;

Level Four bar temperature: 150 DEG C;

Interface temperature: 280 DEG C;

Solvent delay: 5min;

Sample size: 1 μ L; Splitless injecting samples;

Injector temperature: 250 DEG C;

Total run time: 28min.