GC128Introduction to Gas Chromatography:

New Product Details

Listing time:2011year12the moon
Innovation point:Currently, from domestic gas chromatographsFIDCompared to foreign countries, the main technical indicators ofFIDlow,It is mainly reflected in the signal-to-noise ratio of the detector and the collection efficiency of the collector. These two factors directly affectFIDThe main indicator is the minimum detection limit（MDL）. Main innovation separates ignition device and high voltage,The advantage is that it can reduce signal noise,Good assembly reliability and performance,Replacing platinum wire with nickel chromium wire for ignition can greatly reduce manufacturing costs; Increasing the emission area of the polarization pole on the basis of the original nozzle to improve signal collection efficiency,Thereby improving sensitivity and reducing the minimum detection limit.
This instrument adopts a small volumeTCDDetector, *,μ-TCDThe pool structure adopts a straight through dual hot wire structure. The characteristic of this detector is the use of a new process of straight wire pairing and lifting (currently under application), which abandons the triangular hot wire installation structure and achieves the goal of significantly reducing the pool body diameter and thus reducing the pool volume. Another innovation isTCDThe bridge output is directly connected to a low-noise precision amplification circuit, with an amplification factor of up to32Twice.

GC128Main features of gas chromatograph:

Technical pneumatic program control system（PPC）Implement digital flow settings and sensor detection
Feedback and closed-loop control of high-speed electronic valve components;
High sensitivity thermal conductivity cell detector（μ-TCD）And new typesFPD、ECDandNPD，
Embedded microcomputers and multipleCPUSystem development,ITInterface related technology to achieve automatic temperature parameter setting
Detector selection, sensitivity, and polarity digitization settings;
New chromatographic simulation software for chromatographic simulation operation and training

GC128Technical parameters of gas chromatograph:

column oven
Temperature range: room temperature plus5℃～450℃，
Control accuracy:±0.1℃
Temperature deviation:2℃within
Program heating up:6steps/ 7platform
Maximum heating rate:60℃/min
Zui Long Run Time:999.99min
Compensation for loss of dual channel chromatography column
Automatic cooling
injector
Zui can load up to three injectors（2A filling column injection,1Capillary injection)
Sample injector unit: diversion/Non diversion sampler
detector
Zui can load up to three detectors. The detector gas adoptsPPCcontrol
Miniature hydrogen flame ionization detector（μ-FID）：
Temperature range: room temperature plus7℃～450℃
Detection limit:≤8×10-12g/sSample n-hexadecane
Micro thermal conductivity detector（μ-TCD）:
Temperature range: room temperature plus7℃～400℃
Sensitivity:≥10000mV·ml／mg
Electron capture detector（ECD）:
Temperature range: room temperature plus7℃～350℃
Radioactive Source:63Ni 10~12mci
Zui small inspection measurement:0.05pg／sSample:r666
Flame photometric detector（FPD）:
Temperature range: room temperature plus7℃～350℃
Detection limit:≤3×10-12 g／s（P）≤3×10-11g／s（S）
Nitrogen and phosphorus detector（NPD）:
Temperature range: room temperature plus7℃～400℃
Detection limit:≤5pg／s（N）≤0.5pg／s（P）
Carrier gas flow rate:
Carrier gas flow control（EFC）Control of column head pressure（EPC）
Pressure setting range:0~970Kpa
Total flow setting range:0~100ml／min（N2）；0~300ml／min（H2）

GC128Gas chromatograph details:

1）High sensitivity flame ionization detector（Flame ionization detector, FID）
A flame ionization detector is a detector that uses a hydrogen flame as an ionization source to ionize organic matter and generate a micro current in response. Its working principle is that the sample and carrier gas enter the column after passing through itFIDIn hydrogen and air flames, hydrogen and air flames themselves only produce a small amount of ions, but when organic compounds burn, the number of ions produced increases. Polarization voltage attracts these ions to the collection electrode near the flame. The generated current is proportional to the amount of sample burned. Use an ammeter to detect the current and convert it into a digital signal, which is then sent to the output device.
Currently, from domestic gas chromatographsFIDCompared to foreign countries, the main technical indicators ofFIDlow,It is mainly reflected in the signal-to-noise ratio of the detector and the collection efficiency of the collector. These two factors directly affectFIDThe main indicator is the minimum detection limit（MDL）. *One of the most commonly used detectors in gas chromatography isFID,So when choosing a gas chromatograph, users mainly consider this indicator. This technology solves this problem.
The purpose of design is to improveFIDThe collection efficiency of the collection electrode reduces signal noise and improves sensitivity.a.Separate the ignition device from the high voltage,The advantage is that it can reduce signal noise,Good assembly reliability and performance,Replacing platinum wire with nickel chromium wire for ignition can greatly reduce manufacturing costsb.Increasing the emission area of the polarization pole on the basis of the original nozzle to improve signal collection efficiency,Thereby improving sensitivity and reducing the minimum detection limit. Now we have a small detection limitMDLCan achieve≤3×10-12g/s,Belonging to the domestic level.

Programmed pneumatic control system（Programmable Pneumatic Control）
Programmed pneumatic control system（PPC）It is to achieve electronic pressure and flow control of the sampler, detector, and auxiliary of the instrument. By using an electronic drive device to change the flow damper, the pressure and flow can be adjusted. The control unit includes pressure and flow sensors, providing feedback to achieve dynamic display of pressure and flow.PPCThe electronic control board changes the damper based on the actual pressure and flow values compared to the set values to achieve stable and accurate flow and pressure values.
GCThe main microcomputer control system can read all operating parameters of the gas path and transmit control signals toPPCcontroller,PPCController fromGChostCPUThe control system receives the set values of air path parameters, column temperature, and other parametersGCProvide work status and other information, and return it toGChostCPUControl system air circuitPPCThe working status.
PPCThe following functions can be achieved:
Control of carrier gas flow rate and pressure
PPCThe carrier gas flow controller provides a constant flow rate to the chromatographic column. When the temperature of the column box changes or different chromatographic columns are used, the controller increases or decreases the pressure on the column head to maintain a constant flow rate, replacing spring or diaphragm mechanical control valves,PPCBy electronically reading or setting the flow rate, unlike traditional mechanical control valves, it can continuously monitor environmental pressure, chamber pressure, and temperature, and maintain a constant flow output according to the setting.
Control of detector flow (gas)H2Assisting GasAIR）
According to different detector structures, corresponding ones need to be equippedPPCFlow controller. in compliance withFIDDetector, requires a hydrogen gas routePPCFlow controller, another air channelPPCFlow controller;FPDThe detector requires a hydrogen gas routePPCFlow controller, two-way airPPCFlow controller.PPCThe detector flow controller sends a set flow rate to the detector, which is different fromPPCThe carrier gas flow controller does not need to consider changes in gas resistance at the rear, so it cannot be used to provide flow for chromatographic columns,PPCThe detector flow controller can provide a constant airflow and automatically compensate for changes in detector temperature when the gas source pressure fluctuates.
Flow and pressure sensors, as well as proportional valves for air path control, are all imported componentsPPCIt is an independent modular component that contains flow and pressure sensors, proportional valves, circuits, and microcontroller circuit boards. Bus exit is used for communication withGChostCPUControl system communication, one unitGCMultiple hosts can be installedPPCController, different host configurations can provide different combinationsPPCcontroller.
2）High sensitivity thermal conductivity cell detector（μ-TCD）And new typesFPD、ECDandNPD
Micro thermal conductivity cell detector（μ-TCD）
This instrument is a new type of high-sensitivity, commercialized small volume deviceTCDDetector, *, whereS≥10000mV? ml/mgThe volume of the pool is approximately40μl，μ-TCDThe pool structure adopts a straight through dual hot wire structure. The characteristic of this detector is the use of a new process of straight wire pairing and lifting (currently under application), which abandons the triangular hot wire installation structure and achieves the goal of significantly reducing the pool body diameter and thus reducing the pool volume. Another innovation isTCDThe bridge output is directly connected to a low-noise precision amplification circuit, with an amplification factor of up to32Twice.
The detector also added a hot wire protection device, as the gas path system adoptsPPCCan instantly detect the presence or absence of carrier gas flowing throughTCDThe pool body can automatically turn off the power when the carrier gas is not supplied or the carrier gas is reduced, protecting the hot wire from burning out.
Flame photometric detector（FPD） Typical foreign high-endGCofFPDdetection limitMt S：2×10-11g(s)/s(Thiophene sulfur);P：2×10-12g(p)/s(tributyl phosphate). And the fully automated gas chromatographFPDdetection limitMt S：3×10-11g(s)/s(Sulfur in methyl parathion);P：3×10-12g(p)/s(Phosphorus in methyl parathion). From the above, it can be seen that the main technical indicators are close to those of foreign products. stem or root of plantsFPDProposed to adopt a dual flame structure（DFPD）This structure can overcome the single flame typeFPD（SFPD）The disadvantages of easy extinguishing, quenching, sulfur response values often deviating from the square relationship with the flow rate of sulfur atoms entering the flame, and response values related to molecular structure. The optical path system of this detector adopts dual channels（S、PYou can choose any one). The sensitivity selection, zeroing, negative high voltage output, and ignition system of the amplifier are all controlled and set by a microcomputer. stem or root of plantsFPDCan be connected to capillary chromatography columns.
Electron capture detector（ECD） Typical foreign high-endGCofECDdetection limitMt：0.1pg（r-666）. Fully automated gas chromatographECDZui's small inspection measurement is also0.1pgThe detector is a coaxial cylindrical structure and adopts63Ni 10~12mciThe highest operating temperature for the radioactive source is400 ℃High temperature resistant sealing materials are used inside the chamber, which can work under high temperature conditions for a long time, effectively preventing the sample from being damagedECDAdsorption or condensation inside the chamber ensures the sensitivity of the detector and extends its lifespan. The circuit control adopts constant current mode, and the dynamic range can reach104Internally, it features high resolution and precisionADRealize signal conversion, digital output, and microcomputer implementation0.5nA、1nA、2 nAThree modes of current control selection and automatic zeroing.
Nitrogen and phosphorus detector（NPD） Nitrogen and phosphorus detector（NPD）It is one of the selective detectors of gas chromatography, a flameless thermal ionization detector, with a response value of * for organic compounds containing nitrogen and phosphorus. The design work of this project mainly addresses its key components——The selection of rubidium beads should focus on imported rubidium beads with long service life, stable performance, and low cost. At the same time, a circuit control system that matches the new rubidium beads should be developed to match the working conditions of the rubidium beads. The setting and automatic zeroing of rubidium bead current are controlled by a microcomputer, and their technical specificationsDt（N）FromGC122(Our company's product)50pgUpgrade to5pg；Dt（P）From5pgUpgrade to0.5pgIt is comparable in level to similar foreign products.

3）A microcomputer system for fully automatic instrument control and chromatographic data processing, connectedInternetRealize remote communication of instruments
The newly designed fully automatic control and chromatographic data processing microcomputer system can achieveGCSix channel high-precision wide range temperature control, six order programmed temperature control, and gas path system control（PPC）Detector control and chromatographic data processing, completedGCThe comprehensive closed-loop control is beneficial for the self diagnosis of instrument faults and remote control, diagnosis, and teaching through chromatographic workstations. The central control module adopts an embedded microcomputer system, with the main/followCPUControl mode. The central control module implements the following control and exchange functions:
Control display and key input
Programmed pneumatic control system（PPC）Data exchangel
Temperature control module exchanges data;

Data communication of each detector circuit system;
Fully automated gas chromatograph Can be * byPCMachine control, a humanized operation based on the integration of control and data processing;

Connect to the chromatography workstation through a local area network orInternetRealize remote communication of instruments.
4）Based on ChineseWindows NTThe new generation chromatography workstation and chromatography simulation software
Fully automated gas chromatograph with Chinese language proficiency32positionwindowsThe new generation chromatography workstation not only has all the functions of high-precision data acquisition and efficient analysis data processing, but also adds powerful functions such as chromatography simulation teaching, chromatography knowledge base, and bidirectional communication control of chromatography instruments. It is a true chromatography workstation, rather than“Advanced Data Processing Machine'.
The natural spectrum workstation has the following characteristics:
Chromatography simulation teaching Simulate the entire process of gas chromatography analysis on a workstation (computer), by virtually adjusting the main chromatographic parameters such as temperature, flow rate, detector sensitivity, fixed liquid, and chromatographic column type, to simulate peak formation and observe the results of chromatographic separation analysis. Provide a new way to save time, effort, and money in the selection of chromatographic operating conditions. This approach is more intuitive and effective than actual chromatographic experiments for learning the basic theory of chromatography and mastering chromatographic parameters.
Chromatographic knowledge base Including the basic principles of chromatography, the construction of chromatography instruments, an introduction to analytical methods, various standards for chromatography, chromatography and supporting products (instrument functional indicators, fixatives, supports, chromatography columns, etc.), query of retention parameters, Maxwell's constant, etc; Provide calculation programs for commonly used data, such as various reserved values, sensitivity index calculations, etc.
The fully automated gas chromatograph will gather many advanced chromatographic technologies of today, and is a new generation of gas chromatographs in China for the future. It has the characteristics of high performance, high efficiency, high reliability, high automation, and easy operation. Its comprehensive and complete capabilities can meet the needs of every laboratory, and it is suitable for the separation and analysis of organic mixtures in fields such as industrial and agricultural production, scientific research, national defense, and environmental protection.