Waters Xevo G2 QTof Operator's, Overview And Maintenance Manual page 60

Recommendation:
for sample flow rates 1.2 mL/min; use 0.005-inch ID tubing for sample
flow rates >1.2 mL/min.
Requirements:
• If you are replacing the tubing supplied with the instrument, you
must minimize the length of the tube connecting the diverter valve
to the ESI probe. Doing so minimizes delays and dispersion.
• When cutting the tubing to length, cut it squarely (that is,
perpendicular to its horizontal axis).
Long "finger-tight" fitting and PEEK, "finger-tight" nut and ferrule:
3-16 Configuring the LockSpray Source
Diverter valve
Tubing connection
To reduce peak broadening, use 0.004-inch ID tubing
APCI probe
Probe adjuster
assembly