Split/Splitless Inlet, Agilent 6890
Using a Split/Splitless Inlet
This inlet is used for split, splitless, pulsed splitless, or pulsed split analyses.
You can choose the operating mode from the inlet control table. The split mode
is generally used for major component analyses, while the splitless mode is used
for trace analyses. The pulsed splitless and pulsed split modes are used for the
same type of analyses as split or splitless, but allow you to inject larger samples.
Standard and high-pressure versions
The standard split/splitless inlet is rated to 120 psi pressure at the gas supply
fitting. It is appropriate for most columns. The high-pressure inlet is rated to
170 psi pressure—it is useful with very small diameter capillary columns that
offer considerable resistance to gas flow.
To determine the version that you have, press [Front Inlet] or [Back Inlet], scroll
to the Pressure line, and press the [Info] key. The display will show the
pressure range for the inlet—either 1 to 100 psi (for the standard version)
or 1 to 150 psi (for the high-pressure version).
For the standard septum retainer nut, an internal spring in the septum retainer
applies pressure to the septum. For inlet pressures up to 100 psi, tighten the
retainer until the C-ring lifts about 1 mm above the top surface. This is adequate
for most situations.
If using a Merlin Microseal™ septum, finger tighten the septum nut, until snug
(not loose). The pressure capacity depends on the septum used.
Split mode pneumatics
During a split injection, a liquid sample is introduced into a hot inlet where it
vaporizes rapidly. A small amount of the vapor enters the column while the major
portion exits from the split/purge vent. The ratio of column flow to split flow is
controlled by the user. Split injections are primarily used for high concentration
samples when you can afford to lose most of the sample out the split/purge vent.
It is also used for samples that cannot be diluted.
Splitless mode pneumatics
In this mode, the purge valve is closed during the injection and remains so while
the sample is vaporized in the liner and transferred to the column. At a specified
time after injection, the purge valve opens to sweep any vapors remaining in the
liner out the split vent. This avoids solvent tailing due to the large inlet volume
and small column flow rate. Specify the purge time and purge flow rate in the
inlet control table.
Description HP Part No. Qty.
Split/Splitless Inlet EPC Pneumatic Module
(HP part no. G1544-60500, 0–100 psig or G1544-60540, 0–150 psig)
Male Connectors 1/8 in. Swagelok G1543-80030
Screw, M4 x 45 mm, Torx T-20 0515-2484
Inlet Supply Fitting G1543-20510
Screw, M3 x 20 mm, Torx T-10 0515-1319
O-rings, under connectors and fitting (12/pkg) 5180-4182
EPC Valve Replacement Kit G1530-60610
Split Vent On/Off Valve G1544
- Septum Nut 18740-60835
- Split Vent Flow Line (14.2 in. long x 0.125 in. id) G1544-20620
- Swagelok Nut, 1/8 in. brass (10/pkg) 5180-4103
- Swagelok Back Ferrule, 1/8 in. brass (10/pkg) Order No. 5180-4115
- Swagelok Front Ferrule, 1/8 in. brass (10/pkg) Order No. 5180-4109
- Screw, M4 x 12 mm, Torx T-20 (Captive) 1390-1023
- Inlet Weldment G1544-80570
- Heater/Sensor Assembly G1544-61140
- Screw, M4 x 8 mm, Torx T-20, 0515-2711
- Top Insulation G1544-00010
- Washer, 12/pkg 5061-5869
- Thermal Block G1544-20570
- Block Insulation G1544-00020
- Thermal Nut G1544-20590
- Reducing Nut 18740-20800
- Insulation (lower) G1544-00030
- Insulation 19243-00065
- Insulation 19243-00060
- Bottom Insulation Cover 19243-00070
- Column Nut Order No. 5181-8830, 2/pkg) 18740-20870
- Screw, M3 x 16 mm, Torx T-10 1390-1022
- Plastic Fitting, HPM8, (10/pkg) 5181-3394