顶空分析出现鬼峰的维修案例

Core Viewpoint - The article emphasizes the importance of addressing contamination issues in gas chromatography, particularly focusing on the selection and storage of headspace sampling materials to prevent ghost peaks in chromatograms [5][12]. Group 1: Case Overview - A pharmaceutical company's quality control department utilized a Shimadzu gas chromatograph GC-2030 with an HS-20 headspace sampler to measure solvent residues in a drug, encountering numerous ghost peaks in the chromatogram [5]. - The user attempted to clean the headspace sampler using high-temperature steam but did not see any improvement in the ghost peaks [5][10]. Group 2: Chromatographic Analysis Conditions - The chromatographic analysis conditions included: - Column: Rtx-WAX 30m0.32mm1um - Injection port temperature: 220°C - Injection method: Split, split ratio 30 - Injection volume: 1mL - Detector: FID - Column temperature: 40°C (2min) - 10°C/min - 150°C (10min) - Detector temperature: 260°C - Headspace temperature: 80°C - Headspace equilibrium time: 15 min [6]. Group 3: Maintenance Steps - Ghost peaks in the headspace-GC system may arise from residuals from previous experiments or internal contamination of the headspace sampler. The user was questioned about the usage and potential contamination factors [8]. - The headspace sampler had been in use for approximately two years with a relatively low daily workload, suggesting a lower likelihood of instrument contamination [10]. Group 4: Troubleshooting Process - The initial troubleshooting involved running a blank program to check for ghost peaks originating from the gas chromatograph itself, which showed no significant ghost peaks [11]. - Air samples from the laboratory were tested, revealing no significant ghost peaks, indicating that the contamination was not from the laboratory air [11]. Group 5: Identification of Contamination Source - Upon testing with an empty vial, ghost peaks were still present, leading to the conclusion that either the headspace vial or the headspace itself was contaminated [12]. - Further testing with the same vial showed an increase in ghost peak intensity, indicating that the issue was likely with the headspace vial [14]. - The user was advised to change the type and batch of headspace vial septa, which resolved the ghost peak issue, highlighting the importance of proper storage conditions for the vials [14].