14. Disturbances
FlowStar2 LB 514
120
14. Disturbances
This chapter summarizes all possible disturbances, describes them, ex-
plains their cause and provides information on how to eliminate them.
14.1 Electrical or Mains Disturbance
Sparks generated by old refrigerators, centrifuges, electrical switches may
enter the measuring instrument through the mains supply or cables and
cause disturbances in the detector or in the digital unit.
The following steps should solve the problem:
Connect all units which are part of one measuring system (HPLC
pumps, gradient controller, UV detector, integrator, radioactivity flow-
through monitor, computer, etc.) to one mains phase.
Check mass connection, eliminate any possible crossover resistance
or loose contact.
We recommend using mains suppression filters (Schaffner filter - sup-
plied by our Service Department).
14.2 Background (BG)
Table 2 lists typical background values. These values may differ slightly
depending on the setup location.
Cell
cpm
YG-150
YG-400
18 - 20
20 - 25
Z-200
Z-500
Z-1000
5 - 8
5 - 8
6 - 9
J-1000
60 - 100
BGO-X
80 - 120
Table 2: Typical background values for individual measuring cells
The values are valid for brand-new (unused) cells. The typical BG value is
affected by various factors (see Figure 35).