Flow scheme of LH 2.1
A leaking needle can be caused by either loose fittings or air bubbles in the needle tubing, the sample loop, or the buffer tubing.
To flush air out of the sample loop, rinse the sample loop thoroughly with eluent by using the system pump and switching the injection valve into position 2 (INJECT). Please mention that especially preparative sample loops with high volume need some time until they are flushed with at least 5-fold of their volume.
To flush air out of the needle and buffer tubing, perform a needle wash with an appropriate wash volume. The wash volume should be at least the sum of the needle and the buffer tubing volumes. Per default, the needle tubing is 8.1 mL and the buffer tubing is 21 mL.
Additionally, check all fittings and tubings, especially for the forming of new air bubbles, and make sure that there is no leakage at any point of the flow scheme of the liquid handler LH 2.1.
