CN103197023A - Thermal desorption-gas phase-mass spectra combining method for collecting air contaminants based on ionic liquid - Google Patents

Abstract

The invention discloses a thermal desorption-gas phase-mass spectra combining method for collecting air contaminants based on ionic liquid, which belongs to the field of analysis and detection of air contaminants. A preparation method of an ionic liquid adsorption pipe comprises the following steps of: uniformly mixing the ionic liquid and a white supporter in a mass ratio of 1:10 to 1:15, weighting 100-130 mg of the mixture to fill in an adsorption hollow pipe the two ends of which are plugged through glass wool, and carrying out activation on the filled adsorption pipe at 230-280 DEG C; activating the adsorption pipe for 20-30 min under a flow rate of 60-100 mL.min<-1>, and removing impurities, wherein He2 is taken as carrier gas; and after activation, taking out the adsorption pipe when the temperature of the adsorption pipe is reduced to room temperature under ceaseless He2 flow, and placing the adsorption pip in a dryer for later use. The method provided by the invention has the advantages that the operation is simple, the method is easy to master, the solvent extraction is not needed, secondary pollution brought by an organic solvent is alleviated, the time is saved, the method is effective, and the method can effectively control and detect the air contaminants enriched by the ionic liquid.

Description

Gather the method for the thermal desorption-gas phase-mass spectrometry of pollutant in the air based on ionic liquid

Technical field

The invention belongs to Analysis of contaminant detection range in the air, particularly relate to for a kind of enrichment material---the ionic liquid of gathering the air pollutant.

Background technology

Ionic liquid at room temperature refers in room temperature and is close to the special salts substances of being made up of organic cation and inorganic (organic) negative ion under the temperature.It is a kind of novel organic solvent, also is a kind of functional material.The appearance of ionic liquid provides a new selection for the pollutant in the enriched air By.On structure, ionic liquid has abundant electron cloud and unoccupied orbital, in theory with room air in common pollutant good compatibility is arranged, more valuable is that ionic liquid has controllability, can be by selecting suitable negative ion or regulating physical property and the chemical property that kation improves ionic liquid.Therefore, we can be according to the structure of target contaminant, select suitable ionic liquid or as required synthetic new ionic liquid come the enrichment target compound, this also is extremely significant for application of expanding existing ionic liquid.

The gas chromatography-mass spectrography detection method of pollutant and the pre-treatment of sample have important relationship in the air, and whether the method for pre-treatment the result of the direct impact analysis of science, so pretreatment technology is very important to the analysis of sample.

Pre-treating method commonly used at present mainly contains solid phase extraction, liquid-liquid extraction method, ultrasonic extraction method, soxhlet extraction, thermal desorption method etc., the thermal desorption method uses solvent less, and it is simple to operation, so this method according to the suitable sample mode of ionic liquid character design, is set up the detection method of thermal desorption-gas phase-mass spectrometry.

Summary of the invention

Be the airborne pollutant of simple and effective detection, the invention provides a kind of novel functional material---ionic liquid, set up the detection method of thermal desorption-gas chromatography combined with mass spectrometry, the method includes the steps of:

1. the preparation of ionic liquid adsorption tube

Ionic liquid and white carrier are mixed with mass ratio 1:10～1:25, taking by weighing this potpourri 100～130mg inserts in the absorption blank pipe, two ends are stopped up with glass wool, and the adsorption tube that fills is activated with 230～280 ℃ (being lower than ionic liquid thermal decomposition point).With He ₂Do carrier gas, at 60～100mLmin ^-1Flow velocity under activate 20～30min, to remove impurity.After activation finished, the temperature of absorption tube was at uninterrupted He ₂The situation of air-flow drops to room temperature, takes out, and it is standby to put into exsiccator.

2. the preparation of working curve

With the accurate mixed standard solution of drawing 1 μ l variable concentrations of microsyringe difference, inject above-mentioned ionic liquid adsorption tube, measure at thermal desorption and chromatogram mass spectrum condition, be horizontal ordinate with the material concentration, peak area is ordinate, the drawing curve.

3. sampling

Activated ionic liquid adsorption tube is connected with atmosphere sampling instrument with the speed of 0.5～1L/min, the 45～99min that samples in the room.

4. analyze

The sample of ionic liquid adsorption tube collection is directly put into the analysis of thermal desorption-gas chromatograph-mass spectrometer (GCMS).

This method thermal desorption adopts two-stage desorption pattern, and desorption gas is helium; Phase one sample hose desorption, 250～280 ℃ of desorption temperatures, desorption time 15～30min, desorption flow velocity 50～80ml/min; Cold trap trapping temperature-10～10 ℃ (in this temperature range, target compound could quite good detecting come out, if be lower than-10 ℃, DEHP and PBDE-47 then can not detect); Subordinate phase cold-trap desorption, 230～280 ℃ of desorption temperatures, desorption time 1～5min, split ratio 0～9 before 40～99 ℃/s of heating rate, trap, split ratio 0～9 behind the trap; 230～280 ℃ of six-way valve temperature, 230～280 ℃ of transmission line temperature.

This method gas chromatographic column uses HP-5MS chromatographic column (30m * 0.25mm * 0.25 μ m); Carrier gas is helium (purity is 99.995%), flow velocity 1.0ml/min; Initial column temperature is 110 ℃, with 30 ℃/min temperature programme to 210 ℃, keeps 15min, with 30 ℃/min temperature programme to 250 ℃, keeps 10min(under the condition of this temperature programme again, and DEHP can separate preferably with PBDE-47).250 ℃ of transmission line temperature; The EI source, electron energy 70eV, 250 ℃ of ion source temperatures; The ion scan mode is selected in mass scanning scope: m/z35～500.

This method is simple to operate, is easy to grasp, and does not need solvent extraction, has reduced the secondary pollution that organic solvent brings, and saves time effectively, can effectively control and detect the airborne pollutant of ionic liquid institute enrichment.

Description of drawings

Fig. 1 blank [bmim] [NTF ₂] the GC-MS collection of illustrative plates: illustrate and use this method ionic liquid itself not have the organic contaminant that can be detected.

The GC-MS collection of illustrative plates of Fig. 2 mixing reference substance: separation and the mass spectrum identification situation of using this method hybrid standard reference substance are described.

The GC-MS collection of illustrative plates of pollutant in Fig. 3 enriched air By: illustrate and use this method, the PAEs that contains in the mensuration air and the situation of PBDEs.

Embodiment

1. experiment material and medicine

1.1 experimental drug

Ionic liquid at room temperature [BMIm] NTf2(Chinese Academy of Sciences's Lanzhou Physical and Chemical Inst. Green Chemistry and catalytic center) 7 kinds of standard substances (DMP, DEP, DBP, BBP, DEHP, PBDE-28, PBDE-47) (99.4% U.S. Accustandard)), methyl alcohol (HPLC chromatographically pure J﹠amp; K Chemical), 102 pickling white carrier (60～80 order) (the rich auspicious strong chromatographic technique company limited of closing in Tianjin).

1.2 experimental apparatus and equipment

Gas chromatography (Gas chromatograph) model C harus600Perkin Elme company;

Automatic thermal desorption instrument (Auto Thermal Desorbers) model Turbomtrix350Perkin Elme company;

Mass spectrum (Mass Spectrometer) model C harus600T Perkin Elme company;

QC-2 type atmosphere sampling instrument (Beijing three ring work scientific ﹠ trading Co., Ltd.s);

Electronic analytical balance: Sartorius BS110S, precision 0.0001g.

2. method is set up

2.1 the establishment of chromatography-mass spectroscopy condition

HP-5MS chromatographic column (30m * 0.25mm * 0.25 μ m); Carrier gas is helium (purity is 99.995%), flow velocity 1.0ml/min; Initial column temperature is 110 ℃, with 30 ℃/min temperature programme to 210 ℃, keeps 15min, with 30 ℃/min temperature programme to 250 ℃, keeps 15min again.250 ℃ of transmission line temperature; The EI source, electron energy 70eV, 250 ℃ of ion source temperatures; The ion scan mode is selected in mass scanning scope: m/z35～500.

2.2ATD the establishment of condition

Two-stage desorption pattern, desorption gas are helium; Phase one sample hose desorption, 280 ℃ of desorption temperatures, desorption time 15min, desorption flow velocity 50ml/min; 0 ℃ of cold trap trapping temperature, subordinate phase cold-trap desorption, 280 ℃ of desorption temperatures, desorption time 5min does not all have shunting behind the trap before the 40 ℃/s of heating rate, trap; 230 ℃ of six-way valve temperature, 280 ℃ of transmission line temperature.

3. the drafting of working curve

Accurately take by weighing DMP, DEP, DBP, BBP, each 0.1g of DEHP, in methyl alcohol dissolving and constant volume 25ml volumetric flask, be mixed with the storing solution of 4g/l; 50mgPBDE-47 quantitatively is transferred in the volumetric flask of 25ml with methyl alcohol, is mixed with the storing solution of 2g/l; Be that the PBDE-28 of 50mg/l all is transferred in the 5ml volumetric flask with 1ml concentration, be mixed with the 10mg/l storing solution;

Make solvent with methyl alcohol, above-mentioned storing solution is crossed dilution is mixed with 0.1,0.3,1.5,3,5, the standard mixed solution of 10mg/l series concentration, storage is in order to using in 4 ℃ of refrigerators.

Take by weighing white carrier and [BMIM] NTf2,1:15 mixes with mass ratio, toasts 3h in 280 ℃ in muffle furnace.The potpourri that takes by weighing 100mg is respectively inserted in 20 blank pipes, and two ends are stopped up with glass wool, and the adsorption tube that installs is activated 30min with the thermal desorption instrument, and interfering material desorption is wherein come out, and the adsorption tube that activation is good must not have impurity to detect on instrument.

With the accurate mixed standard solution of drawing 1 μ l variable concentrations of microsyringe difference, inject above-mentioned ionic liquid adsorption tube, measure the drawing curve at thermal desorption and chromatogram mass spectrum condition.Linear equation such as table 3.1

Table 3.1 linear equation

4 precision and the recovery

This method is got 5 in the parallel sample of standard solution that concentration is 1.5mg/l, and last machine is tested, and does the analysis of collimation precision, adopts blank recovery of standard addition, and the standard solution that adds 0.3mg/l in blank adsorption tube is done recovery experiment.By formula 4.1,4.2 and 4.3 calculate precision and the recovery respectively

$\mathrm{SD}=\sqrt{\frac{\mathrm{\&Sigma;}{(\stackrel{\&OverBar;}{X}-X_i)}^2}{n-1}}---\left(4.1\right)$

$\mathrm{RSD}=\frac{\mathrm{SD}}{\stackrel{\&OverBar;}{X}}\text{\&times;100\%---}\left(4.2\right)$

Table 4.1 precision and the recovery

Embodiment 1

Use said method, in the laboratory that has experiment cabinet, instrument and equipment, the speed sampling 99min with 0.5L/min measures with adsorption tube.

After sampling finishes, sampling pipe is directly put into thermal desorption, carry out thermal desorption-gas chromatography-mass spectrometry analysis according to the method for setting up.Record the content of target compound in the air shown in table 4.2, accompanying drawing Fig. 3 is the GC-MS collection of illustrative plates of pollutant in the ionic liquid enriched air By.

Target compound concentration in the air that table 4.2 employing this method records

Test findings proof the present invention of embodiment is simple and practical, can effectively analyze composition and the content of major pollutants in the air.

5. sampling of the present invention and detection method are described by embodiment particularly.Those skilled in the art can use for reference links such as content appropriate change raw material of the present invention, process conditions and realize corresponding other purposes, its relevant change does not all break away from content of the present invention, all similarly replace and change apparent to those skilled in the art, all are regarded as comprising within the scope of the present invention.

Claims (6)

1. gather the method for the thermal desorption-gas phase-mass spectrometry of pollutant in the air based on ionic liquid, it is characterized in that:

The ionic liquid adsorption tube is directly put into the analysis of thermal desorption-gas chromatograph-mass spectrometer (GCMS), the preparation work curve be connected sampling with atmosphere sampling instrument after;

Wherein the preparation method of ionic liquid adsorption tube is as follows:

Ionic liquid and white carrier are mixed with mass ratio 1:10～1:25, take by weighing this potpourri 100～130mg and insert in the absorption blank pipe, two ends are stopped up with glass wool, and the adsorption tube that fills is activated with 230～280 ℃; With He ₂Do carrier gas, at 60～100mLmin ^-1Flow velocity under activate 20～30min, to remove impurity; After activation finished, the temperature of absorption tube was at uninterrupted He ₂The situation of air-flow drops to room temperature, takes out, and it is standby to put into exsiccator.

2. in accordance with the method for claim 1, it is characterized in that described ionic liquid is glyoxaline ion liquid.

3. according to claim 1, the method for sampling is, activated ionic liquid adsorption tube is connected speed with 0.5～1L/min at indoor sampled air 45～99min with atmosphere sampling instrument.

4. in accordance with the method for claim 1, it is characterized in that thermal desorption adopts two-stage desorption pattern, desorption gas is helium; Phase one sample hose desorption, 230～280 ℃ of desorption temperatures, desorption time 15～30min, desorption flow velocity 50～80ml/min; Cold trap trapping temperature-10～10 ℃, subordinate phase cold-trap desorption, 250～300 ℃ of desorption temperatures, desorption time 1～5min, split ratio 0～9 before 40～99 ℃/s of heating rate, trap, split ratio 0～9 behind the trap; 230～280 ℃ of six-way valve temperature, 230～280 ℃ of transmission line temperature.

5. in accordance with the method for claim 1, it is characterized in that gas chromatographic column uses the HP-5MS chromatographic column; Carrier gas is helium, flow velocity 1.0ml/min; Initial column temperature is 110 ℃, with 30 ℃/min temperature programme to 210 ℃, keeps 15min, with 30 ℃/min temperature programme to 250 ℃, keeps 10min again; 250 ℃ of transmission line temperature; The EI source, electron energy 70eV, 250 ℃ of ion source temperatures; The ion scan mode is selected in mass scanning scope: m/z35～500.

6. in accordance with the method for claim 1, it is characterized in that, during the preparation work curve, accurately draw the mixed standard solution of 1 μ l variable concentrations respectively with microsyringe, the ionic liquid adsorption tube that injection prepares is measured the drawing curve under thermal desorption and chromatogram mass spectrum condition.

Images