Poor area reproducibility with ACQUITY FTN - WKB99828

SYMPTOMS

• Poor area reproducibility with H-Class

ENVIRONMENT

• ACQUITY UPLC H-Class
• ACQUITY UPLC Sample Manager - Flow Through Needle PLUS (SM-FTN PLUS)
• ACQUITY UPLC I-Class

STRATEGY

1. Perform a leak test on the sample syringe to check if the syringe is leaking - WKB19485

• Replace the syringe if there is a leak
• See video: Replacing the syringe https://videos.waters.com/ja/detail/video/17288689001/replacing-the-sample-metering-syringe?autoStart=true&q=Syringe (This video is available in Japanese only)

2. Perform a needle seal readiness test to check for leaks from the needle seal - WKB99826

• If there is a leak in the needle seal, replace the needle seal

ADDITIONAL INFORMATION

If the peak area value is not reproducible, check for the following as well.

- Insufficient sample amount

　Make sure there is sufficient sample in the vial.

　If the sample is very less, use a small vial for the ACQUITY system.

 

- Confirmation of septum

Waters vial septa are available in "pre-slit" type septa with slits.

When injecting a large volume or injecting multiple times from the same vial, a normal septum is highly airtight and the internal pressure may drop, making it hard to accurately draw the sample injection volume.

Internal pressure can be adjusted by using the slit type.

 

- Check for air bubbles in the sample syringe

If bubbles are found, perform the purge.

 

- Confirmation of drawn amount

Measuring the weight before and after injection can be used as a guide to check whether drawing was performed as the set value.

 (1) Prepare ultrapure water in a sample vial and measure the weight of each vial.

 (2) Inject from the vial in (1) (Example: 10 μL * 10 injections)

 (3) Weigh each sample vial

 (4) Confirm that [Weight of (1)] - [Weight of (3)] = [Theoretical value of (2)]

　★ If the column is connected, check if the ultrapure water can run with the column.

　　　If there is a problem, do it with the column removed.