Guidelines for Daily Maintenance and Troubleshooting of Ion Chromatography Instruments

The stable operation and data reliability of ion chromatography highly rely on systematic daily maintenance and timely fault diagnosis. Following the principle of "prevention first" can reduce downtime.

1、 Key points of core daily maintenance

Mobile phase management: Ultra pure water (resistivity 18.2M Omega) must be used; · Cm) and high-level reagents. All solutions need to be filtered through 0.22 μ m or 0.45 μ m filter membranes and subjected to ultrasonic degassing. Check the amount of rinsing solution daily to avoid pump emptying.

Pump system maintenance: Check daily whether the pump pressure is stable and record the baseline pressure. Regularly (such as weekly) exhaust the pump head and clean or replace consumables such as check valves and sealing rings according to the manual requirements.

Flow path and column protection: Always use online filters or column protection. After the experiment is completed, rinse the chromatography column with a suitable preservation solution (such as pure water or weak base solution for anion column, and pure water or weak acid solution for cation column), and store it according to the specified conditions.

Maintenance of suppressors and detectors: Depending on the type of suppressor, ensure sufficient regeneration or flushing solution and perform regeneration according to the prescribed cycle. The conductivity detector needs to be kept at a constant temperature to avoid the formation of bubbles in the pool.

2、 Quick troubleshooting for common faults

Abnormal pressure:

Excessive pressure: The most common cause is blockage in the flow path. It should be checked in sections, sequentially inspecting the online filter, protective column, and analytical column inlet sieve plate. Reverse flushing or ultrasonic cleaning can be used to clean some components.

Low or fluctuating pressure: Check if there are bubbles or seal ring leaks in the pump, confirm if all joints are tightened, and if the rinsing solution is sufficient.

Baseline issue:

High baseline noise: usually related to the presence of bubbles in the conductivity cell, contamination of the rinsing solution, or unstable temperature. Exhaust can be carried out, fresh shower solution can be replaced, and the column temperature box can be inspected.

Severe baseline drift: may be due to system imbalance, large room temperature fluctuations, or the need for column cleaning and regeneration. Ensure a fully balanced system and stable laboratory environment.

Abnormal chromatographic peak:

Poor reproducibility of peak area: Check the sealing of the injector to confirm the stability of the pumped solution and the uniformity of the sample.

Peak shaped tailing or branching: may be due to decreased column efficiency, column fouling, or excessive dead volume. You can try cleaning or regenerating the chromatography column to check if the flow path connection is tight.

Summary: Establishing and strictly implementing periodic maintenance plans (daily, weekly, monthly, annual), detailed recording of instrument status and maintenance logs, is a strategy to prevent failures and ensure the long-term stable operation of ion chromatography. When encountering complex problems, one should refer to the instrument manual or contact a professional engineer.