Table of Contents
Advertisement
Columns
Many types of LTM columns can be used with the MSD but there are some
restrictions.
During tuning or data acquisition the rate of column flow into the MSD should
not exceed the maximum recommended flow. Therefore, there are limits to
column flow. Exceeding recommended flow will result in degradation of mass
spectral and sensitivity performance.
Remember that column flows vary greatly with temperature. See
Column Flow Linear Velocity"
in your column. Use the Flow Calculation software and
whether a given column will give acceptable flow with realistic head pressure.
Table 4
Feature
High vacuum pump
Optimal gas flow, mL/min
Maximum recommended gas flow,
mL/min
Maximum gas flow, mL/min
Maximum column id
Conditioning columns
Conditioning a column before it is connected to the GC/MSD interface is
essential.
A small portion of the capillary column stationary phase is often carried away
by the carrier gas. This is called column bleed. Column bleed deposits traces of
the stationary phase in the MSD ion source. This decreases MSD sensitivity
and makes cleaning the ion source necessary.
5975T LTM GC/MSD Operation Manual
Gas flows
*
*
Total gas flow into the MSD = column flow
†
Expect degradation of spectral performance and sensitivity.
for instructions on how to measure actual flow
Standard turbo
1.2
2
†
2.4
0.32 mm (30 m)
Installing LTM Columns
"To Measure
Table 4
to determine
2
31
Advertisement
Table of Contents
