Buchi Alltech 3300 ELSD User Manual

BÜCHI Labortechnik AG
www.buchi.com
25
6.3 DIAGNOSING BASELINE NOISE
There are many causes for baseline noise. Use the table
below, Diagnosing Baseline Noise, to help identify the
source.
Start diagnosing the noise at ‘A’ and work down the table until
the source of the baseline noise is determined.
DIAGNOSING BASELINE NOISE
SYMPTOM
SOLUTION
A. Noise from Column
•
Column in-line
•
Mobile phase on
•
Nebulizing gas on
•
Laser on
Result: Noise disappears when column is removed.
1.
The column may be leaking silica or packing material.
Replace the column.
B. Noise from Mobile Phase
•
Column removed
•
Mobile phase on
•
Nebulizing gas on
•
Laser on
Result: Noise disappears when pump is stopped.
1.
Current drift tube temperature and gas flow rate settings may
not be providing adequate evaporation of the mobile phase.
Re-optimize gas flow and/or drift tube temperature following
the optimization procedure in Section 4.6.
2. The nebulizer, drift tube, and/or optics may be dirty. Refer to
Sections 5.1 – 5.4 for cleaning procedures.
3. The mobile phase may be contaminated with particulate
matter. Filter the current mobile phase or replace it with
freshly prepared and filtered mobile phase.
4. The mobile phase may contain excess air bubbles. Degas
the mobile phase.
5. The pump may be the source. Check pump for pulsations.
Make sure the pump has been sufficiently purged to remove
air. Incorporate a pulse dampener into the system if
necessary. Examine the pump check valve and seals and
replace as necessary.
C. Noise from Gas
•
Column removed
•
Mobile phase off
•
Nebulizing gas on
•
Laser on
Result: Noise disappears when gas is turned off.
1.
The gas supply may be contaminated with particulates.
Replace with better quality/higher purity gas.
2. The nebulizer, drift tube, and/or optics may need cleaning.
Refer to Sections 5.1 – 5.4 for cleaning procedures.
D. Noise from Optics Block
•
Column removed
•
Mobile phase off
•
Nebulizing gas off
•
Laser on
Result:
Noise disappears when laser is turned off.
1.
The optics may need cleaning. Refer to
Section 5.4
for
optics cleaning procedure.
2. Check data cable for noise.
3. Check light trap for condensation. Refer to Section 5.4 for
details on removing the light trap.
E. Noise from Electronics
•
Column removed
•
Mobile phase off
•
Nebulizing gas off
•
Laser off
Result:
Baseline noise persists under the above conditions.
1.
Possible electrical problem. Contact your local
BUCHI Customer Service office which can be found
on www.buchi.com.

Buchi Alltech 3300 ELSD Specifications

General

Brand	Buchi
Model	Alltech 3300 ELSD
Category	Security Sensors
Language	English