Low sample probe sensitivity on a Xevo G2-XS - WKB7084

SYMPTOMS

• The counts for the same sample are 10x higher on the LockSpray probe than on the sample probe.
• Switching the fluidics line for the sample and LockSpray does not improve the sample probe counts.

ENVIRONMENT

• Xevo G2-XS QToF
• Xevo G2-XS ToF
• Xevo G2-S QToF
• Xevo G2-S ToF
• Xevo G2 QToF
• Xevo G2 ToF
• Synapt G2-S
• Synapt G2-Si
• Syanpt XS

CAUSE

The probe position is not optimal. 

FIX or WORKAROUND

1. While infusing a sample through the sample probe and monitoring the counts on the tune page, adjust the probe position using the silver micrometer to the left of the sample probe (left arrow in the picture).

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2. Adjust the capillary position for optimal counts using the black ridged collar at the top of the sample probe (top right arrow in the picture). This should tune so that only 0.5 to 1 mm is protruding from the end of the probe tip. 

ADDITIONAL INFORMATION

Optimal settings for infusion vary compared to LCMS injections. Ensure the positions are optimized under the same conditions that data is collected. For example, on install testing, sulfadimethoxine signal is optimized using 0.8mL/min 70:30 water/acn and 20uL/min SDM solution combined flow under acquisition temperatures and gas flows. If checking signal via fluidics infusion, lockspray and sample probes should be similar singal if both are operating correctly.