MicroSI Ion Chromatography
The MicroSI IC kit has been designed to provide a low cost,
user friendly ion
chromatography system ideally suited for environmental, remote monitoring, and
educational applications.
The system can be used with any low pressure ion
chromatography column. The recommended column type is a 5 mm
x
4.6 mm monolithic silica C18 column that the user converts to an
anion exchange column by flushing it with a cationic surfactant. This kind of
column provides decent separation at extremely low backpressures (~25 psi
without suppressor column, ~40 psi with suppressor column).
The
suppressor cartridge can be packed with any strong cation exchange material to
provide a low cost suppressor column that is easy and cheap to renew in the
event of fouling or blockage. The packing material supplied in the kit is Dowex
50 WX8-200 strong anion exchanger. Likewise, the conductivity flowcell has been
designed in such a way that the electrodes can be easily removed for inspection,
polishing etc.
The
suppressor material needs to be periodically regenerated with sulfuric acid, as
is the case for any packed bed type suppressor. The system can be configured so
that regeneration can be carried out without detaching the suppressor from the
system. Alternatively, the system can be set up to periodically (e.g. after
every three sample injection) deliver a bolus of sulfuric acid through the
suppressor column to keep it charged over a longer period of time.
Comparison of suppressed and non-suppressed conductivity
detection. Separation column: Onyx 5 x 4.6 mm C18 column, coated with
didodecyldimethylammonium bromide. Eluent: 1.5 mM 4-hydroxybenzoic acid pH 5.5.