CN105911197B - Automatic sample thermal desorption and liquid phase microemulsion preconcentrate device - Google Patents

Abstract

The invention discloses a heating device, a condensation device, an enrichment device and a controller. The heating device includes a heating body, a heating tank is arranged in the heating body, a quartz sample tube is arranged in the heating tank, and the quartz sample tube is There is a high-temperature Teflon pad on the mouth, and a stainless steel tube is set between the heating body and the quartz sample tube. One end of the stainless steel tube is set in the quartz sample tube, and the other end of the stainless steel tube is connected to a micro flow controller. A nitrogen cylinder is connected, the high-temperature Teflon pad is provided with a needle, one end of the needle is arranged in the quartz sample tube, the other end of the needle is connected with a condensing device, and the condensing device is connected with an enrichment device, the heating body, An electrical connection line is provided between the micro-flow controller and the controller. The invention has the advantages of simple structure, convenient use, low cost, integration of extraction, purification and concentration, less reagent consumption, short enrichment time and high enrichment rate.

Description

Fully automatic sample thermal desorption and liquid phase micro-enrichment device

technical field

The invention belongs to the technical field of analytical chemical gas chromatography sample pretreatment, and in particular relates to a fully automatic sample thermal desorption and liquid phase micro-enrichment device.

Background technique

In the process of gas chromatography sample analysis, sample treatment is a very important step. Solid phase microextraction and liquid phase microextraction are currently the most recommended sample pretreatment techniques. Because the volume of the extraction phase of micro-extraction technology is much smaller than the sample volume, it is defined as micro-extraction, which almost overcomes all the shortcomings of traditional sample processing methods. Among them, liquid-phase microextraction was proposed on the basis of liquid-liquid extraction. This technology integrates extraction, purification, and concentration. It has developed rapidly since it came out, and has entered various fields of analytical chemistry. There are two main types of liquid phase microextraction proposed in recent years. One is airflow headspace liquid phase microextraction, which continuously circulates inert gas into the traditional headspace liquid phase microextraction device to make the enrichment system It becomes an open system and uses heating and cooling devices to achieve a higher enrichment rate than traditional devices, but it is difficult to achieve enrichment for low vapor pressure targets; another liquid phase microextraction technology is gas purging—trace Syringe extraction technology, which is based on the open liquid phase microextraction technology, still uses airflow to drive the analyte into contact with the extraction solvent, and puts the microdrop suspended from the tip of the microsyringe in the liquid phase microextraction into the microsyringe Inside the syringe, the gas flow must completely pass through the liquid layer to escape the extraction system. During this process, the gaseous molecules of the analyte driven by the gas flow are continuously distributed into the extraction solvent. Because the extraction solvent has excellent solubility for the analyte, the analyte Fast access to extraction solvents. Airflow purging-microsyringe extraction technology is a rapid and complete extraction technology of volatile and semi-volatile compounds in samples. It is an integrated sample pretreatment technology. After extraction, samples can be directly analyzed by instruments. However, the airflow purging-microsyringe extraction technology also has some shortcomings: for example, when the injection needle is pulled out from the condenser after extraction, the solvent is easy to fall from the injection needle; the manual operation method is complicated; the injection needle is easy to block and has a short service life and high cost ; The target substance in the syringe is prone to residue during manual elution.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a fully automatic sample thermal desorption and liquid phase micro-enrichment method that is easy to operate, high in enrichment rate, good in reproducibility, and integrates extraction and elution. collection device.

The object of the present invention is achieved like this: it comprises heating device, condensing device and enrichment device, and described heating device comprises heating body, and heating body is provided with heating groove, is provided with quartz sample tube in heating groove, and quartz sample tube tube There is a high-temperature Teflon pad on the mouth, and a stainless steel tube is set between the heating body and the quartz sample tube. One end of the stainless steel tube is set in the quartz sample tube, and the other end of the stainless steel tube is connected to a micro flow controller. A nitrogen cylinder is connected, a needle is arranged on the high-temperature Teflon pad, one end of the needle is arranged in the quartz sample tube, the other end of the needle is connected with a condensing device, and the condensing device is connected with an enrichment device, the heating body, An electrical connection line is provided between the micro-flow controller and the controller.

The condensing device includes a condenser, a circular opening is arranged in the condenser, a sample inner insert is arranged in the circular opening, a square groove is arranged on the circular opening below the sample inner insert, and the bottom of the square groove is LED lighting is provided, and one end of the condenser hose is arranged in the sample insert tube, and the other end of the condenser hose is arranged at the other end of the needle, and there is a set between the condenser, the LED lighting and the controller. Electrical connection wires.

The enrichment device includes a micro-volume peristaltic pump, the outlet of the peristaltic pump is connected with a peristaltic pump syringe connector, the other end of the peristaltic pump syringe connector is connected to the needle of the condenser hose, and the inlet of the peristaltic pump is connected with a solvent bottle. An electrical connection line is provided between the pump and the controller.

A stainless steel connecting pipe is provided between the nitrogen cylinder and the micro-flow controller, a pressure reducing valve is provided on the stainless steel connecting pipe, and an electrical connection line is provided between the pressure reducing valve and the controller.

The heating body, the heating tank and the quartz sample tube are all cylindrical.

The stainless steel tubing is 1/16 inch in diameter.

Due to the adoption of the above technical scheme, a fully automatic sample thermal desorption and liquid phase micro-enrichment device provided by the present invention has the following advantages: simple structure, convenient use, low cost, integration of extraction, purification and concentration, and reagent use The amount is small, the enrichment time is short, and the enrichment rate is high.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

In the figure: 1. Nitrogen cylinder, 2. Pressure reducing valve, 3. Stainless steel connecting pipe, 4. Micro flow controller, 5. Stainless steel pipe, 6. Asbestos, 7. Quartz sample tube, 8. Heating body, 9 , High-temperature Teflon pad, 10. Needle, 11. Condenser hose, 12. Sample insert, 13. Condenser, 14. Peristaltic pump syringe connector, 15. Connecting tube, 16. Peristaltic pump, 17. Solvent bottle, 18, heating tank.

Detailed ways

As shown in Figure 1, the fully automatic sample thermal desorption and liquid phase micro-enrichment device provided by the present invention includes a heating device, a condensation device and an enrichment device, and the heating device includes a heating body 8, which is provided with Heating tank 18, quartz sample tube 7 is arranged in the heating tank 18, high-temperature Teflon pad 9 is arranged on the mouth of quartz sample tube 7, stainless steel tube 5 is arranged between heating body 8 and quartz sample tube 7, stainless steel tube 5 One end is set in the quartz sample tube 7, the other end of the stainless steel tube 5 is connected with a micro-flow controller 4, the micro-flow controller 4 is connected with a nitrogen cylinder 1, and the high-temperature Teflon pad 9 is provided with a needle 10 One end of the needle 10 is arranged in the quartz sample tube 7, the other end of the needle 10 is connected with a condensing device, the condensing device is connected with an enrichment device, the heating body 8, the micro flow controller 4 and the controller are provided There is an electrical connection wire. Described condensing device comprises condenser 13, is provided with circular opening in condenser 13, is provided with sample inserting tube 12 in circular opening, is provided with square groove on the circular opening below sample inserting tube 12 , the bottom of the square tank is provided with LED lighting, and one end of the condenser hose 11 is arranged in the sample inserting tube 12, and the other end of the condenser hose 11 is arranged at the other end of the needle 10, and the condenser 13, An electric connection line is arranged between the LED lighting and the controller. The enrichment device includes a micro peristaltic pump 16, the outlet of the peristaltic pump 16 is connected with a peristaltic pump syringe connector 14, the other end of the peristaltic pump syringe connector 14 is connected to the needle 10 of the condenser hose 11, and the peristaltic pump inlet is provided with A connecting pipe 15, a solvent bottle 17 is arranged on the other end of the connecting pipe 15, and an electric connecting wire is arranged between the peristaltic pump 16 and the controller. A stainless steel connecting pipe 3 is provided between the nitrogen cylinder 1 and the micro-flow controller 4, a pressure reducing valve 2 is provided on the stainless steel connecting pipe 3, and an electrical connection line is provided between the pressure reducing valve 2 and the controller . The heating body 8, the heating tank 18 and the quartz sample tube 7 are all cylindrical. The diameter of the stainless steel connecting pipe 3 is 1/16 inch.

During specific use, put appropriate asbestos 6 at the bottom of the quartz sample tube 7, place the solid or liquid sample to be tested on the asbestos 6, then put the quartz sample tube 7 into the heating body 8, and cover with high-temperature Teflon Pad 9. Fill the sample insert tube 12 with 20-50 μL of extraction solvent, and put it into the circular hole of the condenser 13 . Then the condenser tube 11 is used to connect the quartz sample tube 7 in the heating body 8 with the sample insert tube 12 in the condenser 13 . Introduce nitrogen and adjust the flow rate, set the heating and condensing temperature for enrichment. After the enrichment, 30-50 μL of solvent must be used to elute the residual target substance in the condenser tube 11, and then, the volume should be adjusted to 100-150 μL, and 2 μL should be taken for GC/MS analysis directly. If the concentration of the analyte is low, close the condenser 13 and continue blowing nitrogen to further concentrate. Conventional extraction conditions are as follows: air flow rate 1.5 ~ 2.0mL/min; extraction time 3 ~ 5min; extraction solvent is dichloromethane, butane, etc.; extraction temperature is 250 ~ 300 ° C; condensation temperature is -3 ~ -5 ° C .

The micro-heater heats the solid or liquid sample in the quartz sample tube 7 to 200°C to 400°C to evaporate the volatile or semi-volatile target substance in the sample, and the evaporated target substance passes through the condenser hose under the push of nitrogen 11 is moved to the solvent in the sample insert tube 12 in the condenser 13, at this moment the condensed solvent is all enriched with the target substance. The condenser 13 prevents the solvent from evaporating and increases the enrichment rate, and the condensation temperature is 0°C to -5°C. After enrichment, the needle 10 connected to the high-temperature Teflon pad 9 is pulled out and connected to the syringe connector 14 of the peristaltic pump. The microperistaltic pump 16 pushes the solvent at a rate of 30 μL/min to elute the residual target in the condenser hose 11.

The invention is applicable to gas chromatographic sample pretreatment of solid and liquid samples in the fields of medicine, agriculture, food, chemical industry, quality control and the like.

Claims (1)

1. a kind of automatic sample thermal desorption and liquid phase microemulsion preconcentrate device, which is characterized in that it includes heating unit, condensation dress It puts, enriching apparatus and controller, the heating unit include calandria, heating tank are equipped in calandria, is equipped in heating tank Quartz specimen pipe, quartz specimen pipe nozzle are equipped with high temperature Teflon pad, and stainless steel is equipped between calandria and quartz specimen pipe Pipe, one end of stainless steel tube are located in quartz specimen pipe, and little flow controller, micrometeor are connected on the other end of stainless steel tube Nitrogen cylinder is connected on controller, the high temperature Teflon pad is equipped with syringe needle, and one end of syringe needle is located in quartz specimen pipe, The other end of syringe needle is connected with condensing unit, and enriching apparatus, the calandria, little flow controller are connected on condensing unit Electric connection line is equipped between controller, the condensing unit includes condenser, is equipped with round hole in condenser, circle is opened Sample interpolation pipe is equipped in hole, the round hole below sample interpolation pipe is equipped with square groove, and rectangular trench bottom is equipped with LED photographs It is bright, one end of condenser hose is equipped in sample interpolation pipe, the other end of condenser hose is located at the syringe needle other end, institute Electric connection line is equipped between condenser, LED illumination and the controller stated, the enriching apparatus includes micro peristaltic pump, wriggles Pump discharge is connected with peristaltic pump syringe adapter, and the other end of peristaltic pump syringe adapter is connected to the syringe needle of condenser hose On, wriggling pump inlet is equipped with connecting tube, and the other end of connecting tube is equipped with solvent bottle, between the peristaltic pump and controller Equipped with electric connection line.