Micromass Quattro Ultima, Руководство пользователя

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The APcI Probe
Indications that maintenance to the APcI probe is required include:
•
The probe tip assembly becomes contaminated, for example by involatile
samples if the probe temperature is too low during operation (300°C).
•
The appearance of chromatogram peak broadening or tailing.
Samples that give rise to a good chromatogram peak shape in APcI (for example
reserpine and common pesticides) should display peak half widths of the order
0.1 minutes for 10µl loop injections at a flow rate of 1 ml/min. The appearance
of significant peak broadening or tailing with these compounds is most likely to
be due to a broken fused silica capillary or probe tip heater assembly.
•
Low LC pump back pressure.
For 50:50 acetonitrile:water at a flow rate of 1 ml/min, a LC pump back
pressure less than 14 bar (200 psi) is indicative of a broken fused silica
capillary or a leaking connector.
•
High LC pump back pressure.
For 50:50 acetonitrile:water at a flow rate of 1 ml/min, a LC pump back
pressure above 35 bar (500 psi) is indicative of a blockage or partial blockage
in the fused silica capillary, in a LC connector or in the filter. It is advisable to
change the inner filter pad ( see “Replacing the Fused Silica Capillary” in the
following pages) on a regular basis.
•
Gas flow problems.
Check all gas connections for leaks using soap solution, or a suitable leak
searching agent such as Snoop.
Cleaning the Probe Tip
Remove any visible deposits on the inner wall of the probe heater with a
micro-interdental brush (supplied in the spares kit) soaked in methanol:water.
Before starting an analysis:
With the probe out of the instrument, connect the nebulising gas supply line.
Select
Gas
,
Gas
to turn on the nitrogen.
Allow the gas to flow for several seconds to clear any debris from the heater.
Select Gas , Gas to turn off the nitrogen.
Insert the probe into the source.
Maintenance and Fault Finding
Page 200
Quattro Ultima
User's Guide