Fully automatic thermal analyzerAs a key pretreatment equipment for gas chromatography (GC)/gas chromatography-mass spectrometry (GC-MS) systems, the core technology revolves around "efficient desorption, precise temperature control, automated control, low residue, and high reproducibility". Its core technology can be summarized into the following six categories, which directly determine the accuracy and efficiency of sample analysis:
1、 Precise temperature control and thermal desorption technology
Temperature control accuracy is the core performance indicator of a thermal analyzer, which directly affects the desorption efficiency and recovery rate of the target component
Multi stage programmed temperature rise technology: supports independent multi-stage temperature rise control (usually ≥ 3 stages) for sampling tubes, valve boxes, and transmission lines, with a heating rate of 5-20 ℃/s. It can accurately match the desorption requirements of volatile organic compounds (VOCs) with different boiling points, avoiding the escape of low boiling point components and incomplete decomposition and absorption of high boiling point components.
High precision temperature control module: using PID self-tuning algorithm and platinum resistance sensor, the temperature control accuracy can reach ± 0.1 ℃, and the temperature uniformity is ≤± 0.5 ℃, ensuring reproducibility (RSD ≤ 2%) during batch sample analysis.
Transmission line constant temperature technology: The transmission line is made of quartz or stainless steel material, with a constant temperature throughout the process (adjustable from 50-250 ℃), to avoid condensation and adsorption of target components after desorption during transmission, ensuring that the components enter the chromatographic system intact.
2、 Automated Sample Processing and Injection Technology
Automated design is its core advantage, reducing manual intervention and improving analysis efficiency:
Automatic sample rack and grabbing technology: equipped with a sample rack that can accommodate 10-100 sampling tubes, supporting automatic grabbing, positioning, and loading. Some high-end models support barcode scanning and recognition of sampling tubes, achieving sample traceability and batch continuous analysis (unmanned time can reach 8-24 hours).
Automatic valve switching and flow path control technology: using electromagnetic switching valves or six way valves, the "desorption purge injection" flow path switching is automatically completed through a preset program, with a switching time of ≤ 0.1s, to avoid flow path leakage or component loss caused by manual operation.
Quantitative tube precise injection technology: Built in fixed volume quantitative tube (1-1000 μ L optional), ensuring consistent injection volume each time, combined with pressure balance system, further improving injection reproducibility.
3、 Efficient blowing and capture/secondary desorption technology
For complex samples or low concentration components, the enrichment efficiency can be improved by optimizing the blowing and secondary desorption processes
Dynamic blowing purification technology: high-purity nitrogen (or helium) is used as the blowing gas, and the blowing flow rate can be accurately adjusted (10-100mL/min). Moisture and impurities in the sampling tube are removed through reverse blowing or multi-stage blowing, reducing substrate interference.
Secondary desorption (cold trap focusing) technology: The core is used for low concentration VOCs analysis. The desorbed components first enter a low-temperature cold trap (adjustable from -50 ℃ to room temperature) for focused concentration, and then rapidly heat up (heating rate can reach 50 ℃/s) for secondary desorption, greatly improving detection sensitivity (detection limit can reach ng/m ³ level).
Cold trap material adaptation technology: The cold trap is filled with different adsorbents (such as Tenax, Carbograph), which can be selected according to the polarity and boiling point of the target component to achieve targeted enrichment and avoid component adsorption or loss.
4、 Low residue and cross contamination prevention technology
Avoiding cross contamination between samples is the key to ensuring analytical accuracy, and core technologies include:
Inert treatment of the entire flow path: Sampling tubes, transmission lines, valve components, quantitative tubes and other components that come into contact with the sample are treated with silane or inert coatings (such as quartz coatings, PTFE coatings) to reduce the adsorption residue of active components, with a residual rate of ≤ 0.1%.
High temperature baking and cleaning technology: After each sample analysis, the system automatically performs high-temperature baking (180-300 ℃) on the sampling tube interface, valve body, and transmission line. At the same time, purging gas is used to completely remove residual components and avoid cross contamination.
Independent flow path design: The blowing gas path and the desorption gas path are independent of each other and equipped with gas filtration devices (to remove moisture and oil stains) to ensure the purity of the carrier gas and reduce the impact of external pollution on the analysis results.
5、 Intelligent control system and data linkage technology
Realize precise control and data traceability through intelligent design:
Embedded intelligent control module: equipped with a touch screen or industrial computer, supporting program editing (can store ≥ 100 sets of methods), real-time parameter display (temperature, flow rate, time, etc.), and automatic fault diagnosis (such as insufficient gas pressure, abnormal temperature alarm).
Data collection and export technology: Automatically record key parameters during the analysis process (desorption temperature/time, purge flow rate, injection time, etc.), support USB, Ethernet, RS232 and other interfaces to be linked with the chromatographic workstation, achieve automatic data storage and export (format compatible with Excel, PDF), and meet compliance requirements.
Remote control and calibration technology: Some high-end models support remote monitoring and parameter adjustment through mobile apps or computers, with built-in automatic calibration functions (such as flow calibration and temperature calibration). Regular calibration can ensure long-term stable operation of the equipment.
6、 Structural Optimization and Reliability Technology
The structural design of equipment directly affects operational stability and service life:
Modular design: Separate the temperature control module, valve group module, sample rack module, and gas path module for easy maintenance and repair, and support module upgrades (such as adding cold trap modules and expanding sample rack capacity).
Leak prevention and safety protection technology: The gas path interface adopts a card sleeve or welding connection, with a leakage rate of ≤ 1 × 10 ⁻⁸ Pa · m ³/s; Equipped with safety devices such as over temperature protection, over pressure protection, and gas leak alarm to avoid high temperature or high pressure risks.
Low power consumption and energy-saving environmental protection technology: using efficient heating elements and insulation materials, the temperature rises quickly and energy consumption is low; Some models support standby mode to reduce unnecessary energy consumption and extend the service life of heating elements.