Gas chromatography (GC) is a widely used analytical method for separating and analyzing compounds in various industries. Understanding components, principles, and applications helps optimize their performance and obtain accurate results.

1. Gas chromatography composition

The main components of gas chromatography include:

• Carrier gas system: provides a mobile phase, typically using nitrogen, helium, or hydrogen.
  
• Syringe: Transfer the sample into the system in the form of steam.
  
• Chromatography column: a capillary or packaging column used for separating compounds.
  
• Detector: detects separated compounds, common types include flame ionization detector (FID) and thermal conductivity detector (TCD).
  
• Data system: Record and process signals to generate chromatograms.
  

2. Principles of Gas Chromatography

Gas chromatography operates based on the difference in partition coefficients between the stationary phase (column) and the mobile phase (carrier gas) compounds. Evaporate the sample and pass it through a carrier gas column, where the compound is separated by the interaction between boiling point and stationary phase. Each compound leaves the column with a unique retention time and is detected by a detector.

3. Use of gas chromatography method

Gas chromatography is widely used:

• Pharmaceutical industry: drug purity analysis and quantification of active substances.
  
• Environmental testing: detecting pollutants such as volatile organic compounds (VOCs).
  
• Food and beverage industry: basic analysis, pesticide residue testing.
  
• Petroleum industry: Analysis of hydrocarbons and fuel composition.
  
• Understanding the composition, principles, and applications of gas chromatography is crucial for ensuring the accuracy and reliability of laboratory analysis.
  

Main technical parameters:

● Operation display: 7-inch color LCD touch screen, can be used as a handheld controller

● Temperature control area: 8 channels; temperature control range: 4℃~450℃ above room temperature,

Increment: 0.5℃; accuracy: ±0.1℃

● Program temperature rise steps: 16 steps, program rise rate: 0.1~60℃/min

● Gas path control: full electronic pressure and flow control, range: 0~100Psi (pressure);

0~1000mL/min (flow), resolution: 0.01Psi (pressure);

0.01 mL/min (flow); maximum split ratio: 1:1000

● External events: 8 channels; auxiliary control output 2 channels

● Injector types: packed column injection, capillary injection, six-way valve gas injection,

Automatic injector

● Number of detectors: 3 (maximum); FID, TCD, ECD, FPD and NPD optional

● Start injection: manual, automatic optional

● Communication interface: Ethernet: IEEE802.3

FID detection limit: ≤3×10-12g/S (n-hexadecane)

◆ Baseline noise: ≤2×10-14A (after the instrument stabilizes for 2 hours)

◆ Baseline drift: ≤1×10-13 A/30min (after the instrument stabilizes for 2 hours)

◆Linear range: ≥107

TCD detector: (thermal conductivity bridge circuit has gas cut-off protection function)

◆Sensitivity: S≥6000mv.ml/mg (benzene/toluene)

◆Baseline noise: ≤20uv

◆Baseline drift: ≤30uv/30min

◆Linear range: ≥104