Determination of environmental goitrogen (NIS inhibitors) in drinking water by using ion chromatography

Recent health statistical data show that health problem due to thyroid gland disruption, also known as goiter, has gained a great acceleration in our country and the world within last decade. Despite the fact that the most common reason of the problem has been accepted as iodine deficiency, it was reported that there were no iodine inadequacy in water and food samples collected from the areas where the disease was observed in our country. This case indicates that there may be specific residues, which prevent the usage of iodine by thyroid gland, in water and food samples. In the literature; these substances, which has goitrogenic effects by preventing NIS which has an active role in iodine metabolism in thyroid gland, are called as NIS inhibitors. It was reported that among the most effective inhibitor substances were perchlorate, thiocyanate and nitrate. According to the literature, NIS inhibitors usually were analyzed using ion chromatography with tandem mass spectrometry. However, it is not available in our country because it has high investment costs. In this study, an ion chromatographic method for quantitative determination of NIS inhibitor ions in drinking water was developed and validated in-house in terms of selectivity, linearity, limit of detection, limit of quantification, repeatability, precision, and accuracy. A validated method was been developed for the determination of NIS inhibitor residues in drinking waters using a 'step by step' approach. According to the approach, performance criterions of chromatograms obtained from preliminary studies were been evaluated and optimum conditions that produce the best separation were been determined by adjusting values of system components. At the next step, effects of possible matrix effect (chloride, nitrite, bromate, fluoride, magnesium, ammonium, sodium, potassium, calcium, phosphate, bromide, cyanide) in drinking water were been determined and strategies about these compounds were been improved and the method was been validated. At the last step of the project, drinking water samples in the scope of Antalya municipal were been monitored using the validated method. NIS inhibitor ions, in 5 district of Antalya (Aksu, Döşemealtı, Konyaaltı, Muratpaşa, Kepez) were examined in terms of 189 drinking water samples . The method was found to be selective, linear (R2 =>0.999), precise, and accurate for all of the interested ions. The limits of the detections were estimated at 0.003, 0.004, and 0.025 mg/L for perchlorate, thiocyanate, and nitrate, respectively. Recoveries of the method are between 81.98 and 39.29% for all three ions. The concentration in all drinking water samples were found between 0.85 and 47.71 mg/L in nitrate, Keyword: Guatr = Goiter ; İyon kromatografisi = Ion chromatography ; İçme suyu = Drinking water