INSTRUMENTATION

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Thermo Dionex ICS-5000+ DP pump module w/ a high pressure isocratic pump and a high pressure quaternary gradient pump        (PN 075929)

AS-AP autosampler with a diverter valve (PN 088305)

ICS-5000+ DC/TC detector and temperature-controlled column module (PN 075940)

ICS-5000+ EG eluent generator module (PN 075766) ... (using it for anions)(cations use manually prepared 20 mM MSA)

Two Millipore ICW-3000 water polishing systems ... provides Type I water for reagents, standards, dilutions, and eluents

Data manipulation and instrument control software is Chromeleon 7.2.10 ES MUj

Hamilton Microlab 500 Diluter with a 10-ml diluent syringe and a 5-ml sample syringe

Thermo Dionex CRD 200 4-mm carbonate removal device  (PN 062983)

Thermo Dionex CRD 200 2-mm carbonate removal device  (PN 062986)

Thermo Dionex AS19 4-micron, 2 x 250-mm anion column  (PN 083223)

Thermo Dionex CS16  5 x 250-mm cation column  (PN 079805)​

Thermo Dionex AERS 500 2-mm regenerating suppressor in recycle mode  (PN 082541)

Thermo Dionex ACRS 500 2-mm chemical suppressor in external mode  (PN  085091)

Thermo Dionex CCRS 500 4-mm chemical suppressor in external mode  (PN 085092)

Thermo Dionex CR-ATC 500 continuously regenerated anion trap column (PN 0755550)

Thermo Dionex EGC III NaOH eluent generator cartridge (PN 074533)

The anion method varies depending upon the analytes that are requested.  In all cases the eluent is KOH or NaOH and the concentration varies between 1 and 30 mN depending upon the type of analysis.  For most general water analyses requiring all analytes to be measured a gradient elution is used. This begins with an initial 8 minute equilibration period, followed by an isocratic 1-3 mN hydroxide elution, followed by a linear gradient from 1-3 mN to 35 mN hydroxide at a flow rate of 0.26 ml/min.  The overall time of the elution varies with the age of the analytical column.  Isocratic hydroxide elutions (20 mN) may be used for difficult sulfate measurements in the presence of large amounts of carbonate or bicarbonate.

The cation method is an isocratic elution using 20 mN methanesulfonic acid (MSA) at a flow rate of 1.0 ml/min for approximately 50 minutes.