As a core equipment in the field of chemical analysis, the rigor of the operating procedures of the Thermo Fisher gas chromatography-mass spectrometry directly affects the reliability of experimental results and the service life of the instrument.This article systematically outlines the standardized operation process from four stages: startup preparation, parameter setting, sample analysis, to shutdown maintenance.

　　1、 Power on preparation: laying a stable foundation

1. Inspection of gas source and power supply

Confirm that the pressure of the helium gas cylinder is ≥ 1.5MPa and the pressure of the argon gas is 0.1-0.2MPa to avoid impurities entering the instrument. After turning on the voltage regulator, start the gas chromatography (GC), mass spectrometry (MS), and workstation computer in sequence to ensure that the equipment self-test passes.

2. Hardware status confirmation

Check if the injection port gasket and liner are worn, and replace them if necessary; Confirm that the chromatographic column is installed correctly and tighten the vent valve. For the triple quadrupole TSQ 8000 series, it is necessary to check the oil level and color of the mechanical pump to ensure good lubrication.

　　2、 Parameter setting: precise control of core indicators

1. Optimization of chromatographic conditions

Select the type of chromatographic column based on the properties of the target substance and set the column temperature program. The inlet temperature is usually set at 250 ℃, the carrier gas flow rate is 1.0-1.2mL/min (constant flow mode), and the split ratio is adjusted according to the sample concentration (for high concentration samples, a split ratio of 20:1 is recommended).

2. Mass spectrometry parameter configuration

Set the transmission line temperature (usually 250-280 ℃) and ion source temperature (230-280 ℃) on the MS Device interface, and select Full Scan or Ion Monitoring (SIM) mode. For example, when analyzing polycyclic aromatic hydrocarbons in environmental water samples, SIM mode can focus on specific mass to charge ratios (m/z), increasing sensitivity by more than 10 times.

　　3、 Sample analysis: Full process monitoring to ensure quality

1. Sample injection and operation

Inject 5-10 μ L of sample using an automatic sampler to avoid errors caused by manual injection. Real time monitoring of total ion current (TIC) and observation of signal stability. If the baseline fluctuation exceeds 10%, it is necessary to check the sealing of the injection port or the contamination of the chromatographic column.

2. Data collection and processing

Peak recognition, integration, and quantitative calculation can be completed through Chromeleon or Xcalibur software. For unknown substance identification, combine NIST mass spectrometry library retrieval (matching degree>90%) and retention index validation. For example, in the detection of food additives, precise quantification of nitrite is achieved through the standard curve method (R ² ≥ 0.995).

　　4、 Shutdown maintenance: Extend equipment lifespan

1. Cooling and pressure relief

After the analysis is completed, lower the temperature of the ion source to below 100 ℃ and gradually reduce the flow rate to 0.2 bar before turning off the carrier gas. For the TSQ 8000 series, it is necessary to wait for the turbo pump speed to drop below 10% before turning off the power to avoid damage to the vacuum system.

2. Cleaning and Recording

Regularly replace the chromatography column and clean the ion source. Record instrument usage logs, including running time, maintenance content, and fault symptoms, to provide a basis for subsequent repairs.

Conclusion

Strictly following the operating procedures is the key to ensuring the performance of Thermo Fisher Scientific gas chromatography-mass spectrometry. Through standardized processes, efficient operation from ppb level trace analysis to complex matrix separation can be achieved, providing reliable data support for fields such as environmental monitoring, food safety, and drug development. Operators need to receive regular training to master skills such as tuning and troubleshooting, ensuring that the instrument is always in optimal working condition.