ion chromatograph (ic)
the dionex ics-1100 is a dual channel (anions and cations) ic and includes:
- dionex ics-1100 ion chromatograph with anion and cation self-regenerating suppressors (4mm)
- as40 automated sampler
- as14 column (4 x 250mm)
- cs12a column (4 x 250mm)
- as-dv automated sampler
- chromeleon 7.0 - workstation
theory of operation
anions:
a sample is introduced into a stream of carbonate-bicarbonate eluent and passed via high pressure through a highly basic ion exchange column where anions are separated based on their relative affinity to the column.
cations:
a sample is introduced into a stream of 22mn h2so4 eluent and passed via high pressure through an ion exchange column where cations are separated based on their relative affinity to the column.
analysis:
the peaks with eluent are passed through self-regenerating micromembrane suppressors (anions or cations) where baseline effects from the eluent are reduced. the conductivity of individual peaks is then measured with a conductivity cell.
available methods:
current methods are for trace analysis in water.:
- wica (anions-trace-water)
- wica1 (anions-higher level)
- wicc (cations-trace-water)
wica- water-anions by ic
| anion (cl) | range (ppm) |
| phosphate (o-po4) | 0.050...1.00 |
| chloride (cl) | 0.050...1.00 |
| nitrite (no2-n) | 0.025...1.0 |
| nitrite (no2-n) | 0.025...1.0 |
| nitrate (no3-n) | 0.025...3.2 |
| sulphate (so4) | 0.250...25.0 |
criteria for acceptance of samples are:
- samples do not have visible suspended solids and are not cloudy
- maximum analytical range < 100 ppm for any analyte.
- no organic materials, i.e. humic acid. colored samples may require cleanup before analysis.
- sample ph between 0 and 14
acceptable sample bottles are glass or polyethylene. store at 4 degc. holding times recommended by the epa for trace anions is immediate to 48 hours (sulphate=3 days). samples must not be frozen.
wicc : water-cations by ic
| anion (cl) | range (ppm) |
| sodium (na) | 0.100 - 10.0 |
| ammonium (nh4-n) | 0.010 - 2.50 |
| potassium (k) | 0.100 - 10.0 |
| magnesium (mg) | 0.100 - 10.0 |
| calcium (ca) | 0.100 - 10.0 |
criteria for acceptance of samples are:
- samples do not have visible suspended solids and are not cloudy
- maximum analytical range < 100 ppm for any analyte.
- no organic materials, i.e. humic acid. colored samples may require cleanup before analysis.
- sample ph between 0 and 14
acceptable sample bottles are polyethylene. store at cool to 4 c. glass can cause na leaching.filtration of samples through 0.45 um filters and storage at 4 c will stabilize all analytes for 6 weeks, except nh4+ which is stable for 4 days.