Teledyne ACCQPrep HP125, Installation And Operation Manual

Page: 61 / 142

ACCQPrep HP125
Section 4 Operation
4-15
should be visible with a small gap between
the rods.
· This is not a lamp or detector hardware
problem. These failures will have a corre-
sponding error message.
Peaks elute too early –
• Solvent A not being delivered properly. Check solvent
level, inspect or clean pump A check valves, confirm
solvent lines in correct solvents, look for leaks of air into
the lines.
• Sample injected in a strong solvent that carries the
sample down the column.
• Column not suitable for the compounds separated.
• Fungal or bacterial growth could be obstructing the inlet
filters or effecting the check vales in pump A. Use an
additive, such as 5% B solvent, in the A solvent to
prevent any growth. Be sure to change the aqueous
solvents frequently.
• Incorrect method.
Peaks elute too late –
• Solvent B not being delivered properly. Check solvent
level, inspect or clean pump B check valves, confirm
solvent lines in correct solvents, look for leaks of air into
the lines.
• Check for proper flow rate of both solvents. If flow of one
of the solvents is only half of the expected flow, prime
the system again since one of the pump heads isn
’ t
primed. If still unsuccessful, open the front cover and
tap on the heads of the problem pump.
• Column not suitable for the compounds separated.
• Incorrect method.
Poor peak shape –
• Solvent modifier needed for sample.
• Sample injected in strong solvent.
• Column (or guard column) has voids (or other damage,
such as loss of bonded phase).
“Phantom” or “Ghost” peaks – Sometimes peaks appear as a
broad peak in an area of sharp peaks.
• Wash the column with strong solvent.
• May be caused by a compound left from a prior injection-
ensure that the gradient goes to 100% B in each
separation to ensure all compounds are washed from the
column.