<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec><h3>Background</h3>
<p>Iodine is an essential element for the synthesis of thyroid hormones. Therefore, a reliable marker of iodine supply is important. Iodine is predominantly excreted via kidneys, but also via salivary glands. Our aim was to introduce a new and simple method for determination of salivary iodine concentration (SLIC).</p>
</sec>
<sec><h3>Materials and methods</h3>
<p>Self-prepared chemicals and standards for Sandell-Kolthoff reaction on microplate with ammonium peroxydisulfate (AP) in the range 0−400 µg/L were used. Suitability of water-based standards (WBS) and artificial saliva-based standards (ASS) for standard curve were tested. We followed standards for method validation, defined concentration of used AP and compared our results with Inductively Coupled Plasma Mass Spectrometry (ICP-MS).</p>
</sec>
<sec><h3>Results</h3>
<p>WBS gave more reliable results than ASS as an underestimation of iodine concentration was found for ASS. LoB was 6.5 µg/L, LoD 12.0 µg/L, therefore analytical range was 12−400 µg/L. Intra- and inter-assay imprecisions at iodine concentrations, namely 20, 100, 165, and 350 µg/L were 18.4, 5.1, 5.7, and 2.8%, respectively, and 20.7, 6.7, 5.1, and 4.3%, respectively. Suitable molarity of AP was 1.0 mol/L and showed no difference to 1.5 mol/L (P values for samples with concentration 40, 100, and 150 µg/L, were 0.761, 0.085, and 0.275, respectively), whereas there was a significant change using 0.5 mol/L (P&lt;0.001). Saliva samples could be diluted up to 1:8. There was no interference of thiocyanate and caffeine up to 193.5 mg/L. Our original method was comparable to ICP-MS. Spaerman coefficient was 0.989 (95% CI: 0.984−0.993).</p>
</sec>
<sec><h3>Conclusions</h3>
<p>The new method for SLIC determination is in excellent agreement with ICP-MS and easy-to-use.</p>
</sec>
</abstract>

Background
Iodine is an essential element for the synthesis of thyroid hormones. Therefore, a reliable marker of iodine supply is important. Iodine is predominantly excreted via kidneys, but also via salivary glands. Our aim was to introduce a new and simple method for determination of salivary iodine concentration (SLIC).

Materials and methods
Self-prepared chemicals and standards for Sandell-Kolthoff reaction on microplate with ammonium peroxydisulfate (AP) in the range 0−400 µg/L were used. Suitability of water-based standards (WBS) and artificial saliva-based standards (ASS) for standard curve were tested. We followed standards for method validation, defined concentration of used AP and compared our results with Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

Results
WBS gave more reliable results than ASS as an underestimation of iodine concentration was found for ASS. LoB was 6.5 µg/L, LoD 12.0 µg/L, therefore analytical range was 12−400 µg/L. Intra- and inter-assay imprecisions at iodine concentrations, namely 20, 100, 165, and 350 µg/L were 18.4, 5.1, 5.7, and 2.8%, respectively, and 20.7, 6.7, 5.1, and 4.3%, respectively. Suitable molarity of AP was 1.0 mol/L and showed no difference to 1.5 mol/L (P values for samples with concentration 40, 100, and 150 µg/L, were 0.761, 0.085, and 0.275, respectively), whereas there was a significant change using 0.5 mol/L (P<0.001). Saliva samples could be diluted up to 1:8. There was no interference of thiocyanate and caffeine up to 193.5 mg/L. Our original method was comparable to ICP-MS. Spaerman coefficient was 0.989 (95% CI: 0.984−0.993).

Conclusions
The new method for SLIC determination is in excellent agreement with ICP-MS and easy-to-use.

Introduction of a spectrophotometric method for salivary iodine determination on microplate based on Sandell-Kolthoff reaction

Faculty of Chemistry and Chemical Technology

Radiology and Oncology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Background
Iodine is an essential element for the synthesis of thyroid hormones. Therefore, a reliable marker of iodine supply is important. Iodine is...

Introduction of a spectrophotometric method for salivary iodine determination on microplate based on Sandell-Kolthoff reaction

Article Category: Research Article

Published Online: Jul 22, 2024

Page range: -

Received: Apr 16, 2024

Accepted: May 28, 2024

DOI: https://doi.org/10.2478/raon-2024-0035

Keywords
iodine, salivary iodine concentration, Sandell-Kolthoff reaction, Inductively Coupled Plasma Mass Spectrometry

© 2024 Adrijana Oblak et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Introduction of a spectrophotometric method for salivary iodine determination on microplate based on Sandell-Kolthoff reaction

Article Category: Research Article

Published Online: Jul 22, 2024

Page range: -

Received: Apr 16, 2024

Accepted: May 28, 2024

DOI: https://doi.org/10.2478/raon-2024-0035

Keywordsiodine, salivary iodine concentration, Sandell-Kolthoff reaction, Inductively Coupled Plasma Mass Spectrometry

© 2024 Adrijana Oblak et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
iodine, salivary iodine concentration, Sandell-Kolthoff reaction, Inductively Coupled Plasma Mass Spectrometry