BUCHI ELS Detector C-650 - Manual (Page 38)

C-650 Operation Manual, Version B 6 Operation 38
6 Operation
This chapter describes the operations that should be performed on a routine basis when you
want to collect chromatographic data using the C-650 and gives examples of typical device ap-
plications and instructions on how to operate the device properly and safely.
6.1 Preparing the device for operation
CAUTION
Risk of fire due to flammable liquids!
• Check all tubes for correct connection before starting the device.
• Make sure all tubes are in good condition (no cracks or cuts).
To prepare the detector for operation:
• Power up the detector by pressing the switch on the rear panel.
• Open the gas distribution valve and set the pressure to 2 bar (29 psi). The pressure is indi-
cated on the Status screen.
• Ensure that the overflow siphon for the nebulization chamber contains sufficient liquid. If
necessary, pump few mL of solvent through the device to fill the siphon.
• Select the desired temperature. The temperature is set on the Temp/Gain screen, which is
accessed by pressing the
button two times when the Status screen is displayed.
• Start the mobile phase flow through the device and allow the overall system to operate for
at least 15 minutes to ensure that all components are equilibrated and a stable baseline is
obtained.
• Switch on the LED light source of the detector by pressing the LED button on the control
panel.
NOTE
The Solvent Noise test (section 5.9.4) and the Column Noise test (section 5.9.5) should be per-
formed to verify that the detector is functioning in a proper manner.
NOTE
The liquid level in the siphon must be stable and should be equal at both sides.
6.2 Auto-zeroing the detector
6.2.1 Manual
To auto-zero the detector:
• Set the Gain to the desired value. The gain is set on the Temp/Gain screen, which is ac-
cessed by pressing the
button two times when the Signal screen is displayed.
• Press the “ZERO” button. The detector will be automatically auto-zeroed at this point.
• If the signal is to be offset, set the offset at this time. The Offset screen is accessed by
pressing the
button when the Status screen is displayed.
NOTE
The offset must be selected after the detector is auto-zeroed, as the Auto-zero operation sets
the signal to 0.
NOTE
If you change the gain selection, make sure that the detector is auto-zeroed again before taking
any measurement.