design and fabrication of electrochemical sensor for determination of thyroxine

Abstract: thyroid hormones including thyroxine (t4) and triiodothyronine (t3) are hormones derived from the amino acid tyrosine that are produced and secreted by thyroid gland. the main form of thyroid hormone (about 95%) secreted in the blood is t4. despite the conversion of t4 into t3 in the surrounding tissues, the amount of t4 in the blood is still much higher than t3 [1]. generally measuring t3 is not vital. at the beginning of hypothyroidism, t4 decreases, but because t4 is converted to t3 in the surrounding tissues, the amount of t3 does not decrease and most of t4 molecules are converted to t3. therefore, despite the fact that there is an inverse relationship between t4 and tsh in these conditions, there is not much change in the amount of t3. consequently, its measurement does not help in diagnosis. considering the biological importance of t4 hormone, it is very important to determine it to diagnose hyperthyroidism or hypothyroidism [2-4]. since t4 is an electroactive material, its electrochemical behavior at an aggo-chit modified carbon paste electrode was investigated in this work. thyroxine underwent totally irreversible oxidation in this system and a well-defined peak at 0.42v was observed. the influence of various nanoparticles on the oxidation of thyroxine was examined through cyclic voltammetry. in the range of 10−9 to 10−4 mol/l, with the oxidation peak current was linear with the thyroxine concentration. abstract: thyroid hormones including thyroxine (t4) and triiodothyronine (t3) are hormones derived from the amino acid tyrosine that are produced and secreted by thyroid gland. the main form of thyroid hormone (about 95%) secreted in the blood is t4. despite the conversion of t4 into t3 in the surrounding tissues, the amount of t4 in the blood is still much higher than t3 [1]. generally measuring t3 is not vital. at the beginning of hypothyroidism, t4 decreases, but because t4 is converted to t3 in the surrounding tissues, the amount of t3 does not decrease and most of t4 molecules are converted to t3. therefore, despite the fact that there is an inverse relationship between t4 and tsh in these conditions, there is not much change in the amount of t3. consequently, its measurement does not help in diagnosis. considering the biological importance of t4 hormone, it is very important to determine it to diagnose hyperthyroidism or hypothyroidism [2-4].since t4 is an electroactive material, its electrochemical behavior at an aggo-chit modified carbon paste electrode was investigated in this work. thyroxine underwent totally irreversible oxidation in this system and a well-defined peak at 0.42v was observed. the influence of various nanoparticles on the oxidation of thyroxine was examined through cyclic voltammetry. in the range of 10−9 to 10−4 mol/l, with the oxidation peak current was linear with the thyroxine concentration.