Spectrophotometric Measurement of Lithium in Human Saliva Using the Chromogenic Reagent Thorin
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Published:2023-09-20
Issue:3
Volume:70
Page:430-439
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ISSN:1580-3155
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Container-title:Acta Chimica Slovenica
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language:
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Short-container-title:ACSi
Author:
Levitt Stephen R.
Abstract
The feasibility of using the chromogenic dye Thorin to spectrophotometrically measure lithium concentration in human saliva was explored. Absorbance wavelength maximum of the Li-Thorin complex was found to be 480 nm. Absorbance at 480 nm was obtained for saliva calibration standards containing 0.00–5.29 mEq/L of lithium. A least-squares fit produced a regression equation y = 0.128x + 1.449, R = 0.997. This was used to predict lithium concentrations in both artificially prepared lithium/saliva test solutions and in hospitalized patients treated with lithium. Results agree well with atomic absorption spectroscopy. Using a reagent blank with an equivalent amount of saliva as the test samples eliminated protein and electrolyte absorbance interference. This study supports the continued exploration of this method as a non-invasive point-of-care testing approach for monitoring saliva lithium in bipolar disorder.
Publisher
Slovenian Chemical Society