최영우 (인제대학교)

곽영범 (인제대학교)

최영우 (인제대학교)

한장미 (인제대학교)

곽영범 (인제대학교)

Liquid chromatography–mass spectrometry (LC–MS) is widely used for pharmaceutical and biological sample analysis. The HPLC autosampler is a key component for accurate sample injection and reproducible analysis. Mechanical failures and communication errors can interrupt operation and reduce data reliability, making systematic troubleshooting essential. This study investigated two failure cases in an Agilent 1200 HPLC autosampler and established a stepwise troubleshooting strategy.

In the first case, the needle arm failed to return to the home position during initialization, causing repeated contact between the needle and the needle seat. As a result, the needle arm was deformed, and the inner surface of the needle seat was scratched by the needle, resulting in solvent leakage and increased system pressure. Mechanical inspection confirmed the physical damage. Replacing the needle arm, needle, and needle seat restored normal initialization, eliminated the leakage, and returned the system pressure to the normal operating range.

In the second case, the autosampler failed to initialize, the status indicator remained off, and the module stayed offline in ChemStation despite normal power status. A systematic diagnosis of the CAN communication cable, power supply, module connections, and software configuration was performed. Since the other HPLC modules operated normally, external connections and software settings were excluded. The communication board of the autosampler was identified as the likely source of the failure, indicating that replacement of the communication board is required.

These cases demonstrate that systematic troubleshooting can effectively distinguish between mechanical and electronic failures in an HPLC autosampler. The proposed troubleshooting workflow can improve maintenance efficiency, reduce instrument downtime, and enhance the operational reliability of LC–MS systems.