Ionchromatography

Determination of iodine:
APPARATUS:
Software: Pyramid  1.940
Sykam; S1100 Solvent Delivery System
Sykam, S3111 Column Heating Modul
Sykam, S3110 Conductivity Detector
Sykam, S2210 Regeneration Valve Controller
Column: Anion exchange column LCA A14
UV-Detector:  LINEAR UVIS 200
Autosampler: Spark Holland Basic+ Marathon
Filtrationunit SARTORIUS + cellulose acetate filter (poresize 0.2 µm )
Eppendorfpipettes (500- 2500 µl and 10-100 µl))

REAGENTS:
80 mM NaCl-solution (eluent)
KI stock-standard (5 mg KI in 100 cm3 NaCl-sol. = 0.302 mmol/l)

MEASURING CONDITIONS:
Flow rate: 1.9 cm3/min.
Temperature of the column heater: 70 °C
Injection volume: 20 µl
Injection method: Loop-Fill (Total)

SETTINGS AT THE UV-DETECTOR:
Range 0.2
Rise time 3.0
Wavelenght: 232 nm

PREPARATION OF THE SAMPLES:
The samples are diluted in the ratio 1:10 with eluent. The samples are filtrated (cellulose-acetate filter; poresize 0.45 µm) to remove all particles.

MEASUREMENT:
The samples are injected by the autosampler, transferred to the column and separated there. With this method you detect the Iodine-ions with a UV-detector.
Every sample is measured twice. We measure the peak-area.

CALIBRATION:
For the calibration the KI stock standard is diluted with the eluent in different concentrations. Calibration curves are calculated with the pyramid-software.

CALIBRATION RANGE:
0.0466 -1,466 µM

CALCULATION:
The calculation is done by the pyramid-software using peak areas and calibration curves (for iodine in mol/dm3).
In every batch (about 50 samples) 5 KI-standard are measured to check the system and the eluent.