Components that do not carry over with ACQUITY UPLC H-Class carry over with 2695 Separations Module - WKB89997

SYMPTOMS

• Carryover is seen from the beginning when using this method with 2695
• The area of the target component is about 8 million from the sample injection; the blank injection performed immediately after the sample injection has a peak of ~10,000 at the same time as the target component; the peak disappears in the next blank injection
• In H-Class, no peak detected from the injection immediately after the sample injection
• Reducing the blank injection volume to 10 μL (usually the blank is also 50 μL) after the 50-μL sample injection, the area value of the carryover peak does not change
• Performing immediate injection after the sample injection of 50 μL, the area value of the carryover peak does not change
• Column is the same as the one used for confirming that there is no carryover in H-Class (thus, the column is not the cause)

ENVIRONMENT

• 2695 Separations Module
• 2489 UV/Vis Detector

CAUSE

Sample remains somewhere in the flow path.

FIX or WORKAROUND

1. Change the needle wash time to Extended. Or, if this does not work, change the needle wash to one that allows the sample to dissolve easily.

2. If solution 1 does not help, perform immediate injection (stainless steel, 0.009 inch) with the in-line filter outlet connected directly to the column.
After injecting the sample with the normal flow path, use the above flow path to perform immediate injection.
If a carryover peak still occurs, it is certain that the cause is not the injector.

3. If Solution 2 does not help, the assemblies after the column should be considered. Either the tube from the column to the detector or the cell of the detector could be the cause.
Because the 2489 detector cell is made of stainless steel and the H-Class UV detector cell is made of resin, it is difficult to verify the difference.
Because the 2489 cell inlet tube is integrated with the cell, it’s impossible to connect the tube from the column outlet to the detector (TUV detector cell inlet tube) on H-Class to 2489.
The 2489 has an inert cell, but replacing it might not be helpful.

ADDITIONAL INFORMATION