CP-3800 GC Getting Started Manual
39
Basic Operation
IMPORTANT Note: At points throughout this section, specific values and conditions are
given for analysis of the Varian test samples on Varian test columns.
Your analytical column and application may require different values
and conditions. Please ascertain the range of operating
temperatures for your analytical column and make sure your settings
are within this range.
Setting Carrier and Detector Gas Flow Rates
The following table indicates the typical values for carrier and detector gas
flow rates. For practical purposes a generalized carrier gas flow rate of 2
mL/min is used for capillary columns. Note that the carrier gas and make-up
combined flow is typically 30 mL/min.
Table 2 Flow Rates for Carrier and Detector Gases for the 3800 Gas Chromatograph
Detector
Carrier
Gas
Carrier Gas Flow Rate
(mL/min)
Packed Capillary
Make-Up
Gas
Make-Up +
Carrier
Gas Flow
Rate
(mL/min)
Detector
Gas
Air 1
(mL/min)
Detector
Gas
Air 2
(mL/min)
Detector
Gas
H
2
(mL/min)
ECD N
2
or
Ar/CH
4
30
±
1 1 - 15 N
2
or
Ar/CH
4
30
±
1 —
—
—
FID N
2
, H
2
or
He
30
±
1 1 - 15 N
2
or He 30
±
1 300
±
10 — 30
±
1
TCD* N
2
, He or
H
2
30
±
1 1 - 15 Same as
Carrier
Gas
30
±
1 —
—
—
PFPD N
2
, He or
H
2
30
±
1** 1 - 10 None __ 17
±
1 10
±
1 13
±
1
TSD N
2
or He 30
±
1 1 - 15 Same as
Carrier
Gas
30
±
1 175
±
10 — 4
±
0.2
Micro-
TCD***
H
2
, or He — 1 – 5 None —
*
TCD Reference Flow – Rate for carrier gas flow through the reference cell is 30
±
1 mL/min.
** PFPD with packed columns – an effluent splitter is used to reduce the carrier flow to the detector
to < 5 mL/min.
***Micro-TCD reference flow is provided by a reference column of the same length and ID as the
analytical column.
