Hesi-Ii Probe Maintenance - Thermo Scientific LTQ Series Hardware Manual

Installing an Optional Metal Sample Tube

HESI-II Probe Maintenance

Flushing the Sample Transfer Line and Sample Tube
Replacing the Needle Insert
Thermo Scientific
You can configure the ESI probe to use a stainless-steel metal sample tube rather than a
fused-silica sample tube. Two kits are available, one that includes a 32-gauge metal sample
tube for typical flow rates used in ESI and another with a 34-gauge metal sample tube used for
low-flow applications. Both kits include instructions for installing the stainless steel sample
tube. For part numbers, see
The HESI-II probe requires minimum maintenance. If the metal sample tube is plugged,
replace it. Replacing the metal sample tube requires a partial disassembly of the probe.
CAUTION HOT SURFACE At operating temperatures above 350 °C (662 °F), the probe
and API source housing can severely burn you.
• Before removing the probe or API source housing, allow the part to cool to room
temperature (approximately 20 minutes) before touching it.
• If the mass spectrometer connects to an LC system, leave the solvent flow from the
LC pump on while the probe cools to room temperature.
To maintain the HESI-II probe, follow these procedures:
• Flushing the Sample Transfer Line and Sample Tube
• Replacing the Needle Insert
You can minimize cleaning of the probe components by flushing the sample transfer line,
sample tube, and probe at the end of each work day (or more often if you suspect they are
contaminated). To remove contamination, use a 50:50 solution of LC/MS-grade methanol
and LC/MS-grade water, and flush the solution from the LC system through the API source
for approximately 15 minutes. For instructions, see
Sample Tube, and API Probe"
If the metal sample tube is plugged, you can replace the needle insert. The needle insert is
assembled at the factory and consists of an adjustable union, needle guide fitting, ferrule,
O-ring, ESI needle, and metal sample tube
needle. Factory adjusted, the metal sample tube protrudes 0.5 mm from the end of the ESI
needle (Figure 43).
To support flow rates of 5–2000 μL/min, Thermo Fisher Scientific provides two metal needle
inserts for the HESI-II probe. The difference between the two inserts is the size of the metal
needle and supporting ferrule. For part numbers, see
page 132.
"Ion Source Probes and Parts"
"Flushing the Sample Transfer Line,
on page 49.
(Figure 42). The ferrule is swaged onto the ESI
Ion Source Probe Maintenance
on page 132.
"Ion Source Probes and Parts"
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