Determination of chloride, sulfate and bromide:
DEVICES:
METROHM Eco IC Compact IC system with integrated conductivity detector and suppressor unit; Column: Metrosep A Supp 5 150/4.0; 788 IC Filtration Sample Processor (autosampler); Software: MagIC Net 3.3
REAGENTS:
Eluent: 3.2mM NaCO3 /1mM NaHCO3
Standard: IAPSO seawater standard
RUNNING CONDITIONS:
Flow rate: 0.7 ml/min.
Injection volume: 10 µl
SAMPLE PREPARATION: The samples are diluted 1:50 (with eluent) before measurement.
MEASUREMENT: The samples are applicated by a computer-controlled autosampler and separated on a ionchromatographie column. The peak area is measured.
CALIBRATION: Calibration is carried out using an IAPSO standard which is measured in different concentrations, from which the corresponding calibration curves are then produced using a calibration program.
EVALUATION AND CONTROL: The evaluation is carried out using the device software. This means that measured peak areas are "compared" with the calibration curves and output as actual concentrations.
CALIBRATION RANGE:
Chloride: 2237.2µM to 22372µM
Sulfate: 115.72µM to 1157.2µM
Bromide: 3.452µM to 34.52µM
Determination of iodide (from December 2008):
DEVICES:
METROHM 881 Compact IC pro, IC system with integrated conductivity detector and suppressor unit; UV detector Lambda 1010; Column: Metrosep A Supp 5, 250/4.0; 885 Professional Sample Processor (autosampler); Software: IC-Net
REAGENTS:
Eluent: 10g/l NaCl (0.171 mol per liter)
Standard: KI standard (1g/l)
RUNNING CONDITIONS:
Flow rate: 0.7 ml/min.
Injection volume: 20 µl
Temperature of the column oven: 25°C
SETTINGS ON THE UV DETECTOR: Wavelength: 230 nm
PREPARATION OF THE SAMPLES: The samples are diluted 1:6 with filtered eluent before measurement.
MEASUREMENT: The samples are applicated by a computer-controlled autosampler and separated on a ionchromatographie column. The peak area is measured.
CALIBRATION: Calibration is carried out using a KI standard which is measured in different concentrations, from which the corresponding calibration curves are then obtained using a calibration program.
EVALUATION AND CONTROL: The evaluation is carried out using the device software. This means that measured peak areas are “compared” with the calibration curves and output as actual concentrations (unit µmol/l). For control and error determination, approximately 6-7 standards with a known concentration are measured for each run (approx. 130 samples).
CALIBRATION RANGE: Iodide: 0.1379µM to 8.6237µM
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Determination of iodide (before December 2008)
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.
