Metrohm 732 IC Detector - Manual (Page 140)

5.1 Practical notes on ion chromatography
732 IC Detector / 733 IC Separation Center
133
5 Notes – Maintenance – Faults
5.1 Practical notes on ion chromatography
5.1.1 Separating columns
Separation efficiency
The attainable quality of analyses with the 732/733 IC system depends
to a large extent on the separation efficiency of the column used. When
purchasing an IC column you should ensure that the separation effi-
ciency suffices for the analysis problems at hand. Ascertain the char-
acteristic data of the IC column on the standard chromatogram en-
closed with the column such as capacity factors, selectivity, plate
number and resolution and check these data with your own measure-
ments. If any difficulties arise, you should always first check the quality
of the column by recording a standard chromatogram.
You will find additional general tips on handling IC separating columns
in the 8.732.2003 Metrohm Monograph "Ion chromatography"", as
well as detailed information on the separating columns available from
Metrohm (see section 7.3.2) in the leaflets supplied and in the special
Application Bulletins available free of charge from your nearest
Metrohm agency.
Protection
To protect the column against foreign particles which could have an
adverse influence on the separation efficiency, we advise you to subject
both the eluents and all samples to microfiltration (0.45 µ m filter) and
to siphon the eluent through the 6.2821.090 Aspirating Filter.
To avoid contamination by abrasive particles arising from piston seals
of the 709 IC Pump, it is advantageous to install an in-line filter be-
tween the pump and the 733 IC Separation Center. The 6.2821.100
Filter unit PEEK (see section 2.6.3) supplied with the 709 IC Pump for
operation with PEEK capillaries in the pressure range 0 … 25 MPa and
the optional 6.2821.000 Filter unit Manufit (see section 2.6.4) for op-
eration with steel capillaries in the pressure range 0 … 50 MPa are emi-
nently suitable for this purpose.
The use of readily interchangeable precolumns serves to protect the
actual separating columns and increase their service life appreciably.
The precolumns available from Metrohm (see section 7.3.2) are either
actual precolumns or so-called precolumn cartridges which are used
together with the 6.2821.050 Twin cartridge holder or the 6.2828.010
Precolumn cartridge holder (see section 2.7).
Storage
Always store the separating columns closed when not in use and filled
in accordance with the manufacturer’s specifications.