Troubleshooting; Chromatographic Symptoms - Agilent Technologies 8860 User Manual

6 Maintenance and Troubleshooting

Troubleshooting

Troubleshooting

Chromatographic symptoms 47

Gasifier Not Ready Symptoms 51
Thermal Fault 52
Electronics Troubleshooting GC Power-On and Communication Symptoms 53
Checking for Leaks 53
Checking for Blockage 54
Chromatographic symptoms
Success in flash vaporizing of pressurized liquid sample is largely a matter of ensuring the sample
fluid remains at the right flow, pressure and temperature. Controlling those three conditions might
be enough to eliminate many of the problems jeopardizing the subsequent GC result.
Peak areas not repeatable
• Check if the gasifier temperature zones are stabilized.
• Check if the flushing time is long enough to fill the gas sampling loop with representative
sample
• Check peak area variation patterns of the run replicates: if the response change of low boiling
point compounds and high boiling point compounds are out phased, it means fractionation
happens. It can be caused by:
• Low sample bomb pressure, samples are already partially vaporized in the cylinder. A
It is strongly recommended that the sample is pressurized to at least 1380 kPa above the vapor
NOTE
pressure of the mixtures at all times.
• Samples are partially vaporized before entering the gasifier. If so, the tubing between the
• Gasifier vaporizer temperature is not high enough to fully vaporize high boiling point
• Check for leaks (See
• If it's not caused by sample or gasifier, it may be caused by GC system. Refer to GC
troubleshooting manual to fix the problem.
Agilent 8860, 8890, and 990 Micro GC Gasifier User Manual
partially filled sample cylinder will lead to discrimination due to evaporation inside the
bottle. As a rough guideline, the bomb must be filled with 80% liquid. Increase the sample
cylinder pressure (required pressure depends on the partial pressure of the sample
constituents).
cylinder and gasifier may be cold to touch or even form frost or ice. Agilent Gasifier
includes a pressure reducing regulator and flow adjusting needle valve that are essential
for flash vaporizing. Please don't add unnecessary needle valve or restrictions not
provided in the installation kit between sample cylinder and the gasifier inlet. Such
components lead to pressure drop. The sample pressure drop may release a dissolved
gas, thus causing the liquid to bubble or foam. Remove those pressure reducing
components.
components. Increase the gasifier vaporizer temperature.
"Checking for Leaks" on page 53.)
47