Iodine is an essential mineral, which must be ingested by nutrition. The thyroid hormones T3 (triiodidethyronin) and T4 (tyroxin) are built by the addition of iodine to the amino acid tyrosin. T3 is much more effective than T4. T3 is taken up into the cells and binds to receptors of the nucleus. T3 activates a lot of metabolic pathways. It increases body temperature and oxygen consumption. T3 accelerates the ingestion of carbohydrates, activates the release of fat, supports the turnover of cholesterol and the protein synthesis. It regulates the water balance, the bone metabolism and is indispensable for the maturation of skeleton and brain.
The measurement of free iodide in urine is a valuable tool for the determination of the supply with iodine, especially for the diagnosis of a lack of iodine and the control of struma genesis. The measurement of the direct intake of iodine is rather difficult. Therefore the determination of iodide in urine is well accepted as an index of iodine uptake. The fecal excretion is negligible.
Sample volume 2 ml
Detector Electrochemical detection, Ag-working electrode
IC3100ko Controls (2 level each 3 ml lyoph.)
IC3100rp HPLC column
Principle of the method
For the determination of free iodide the samples are extracted on solid phase extraction cartridges. The probe is centrifuged and 50 µl of the supernatant are injected into the HPLC system.
The isocratic separation via HPLC at 30°C using a „reversed phase“ column. One run lasts 10 minutes. The chromatograms are recorded by a electrochemical detector with a silver working electrode. The quantification is performed with the delivered standard; the concentration is calculated via integration of the peak areas or heights.