Spectrophotometric Measurement of Lithium in Human Saliva Using the Chromogenic Reagent Thorin

The feasibility of using the chromogenic dye Thorin to spectrophotometrically measure lithium concentration in human saliva was explored. Absorbance wavelength maximum Li-Thorin complex found be 480 nm. at nm obtained for calibration standards containing 0.00–5.29 mEq/L lithium. A least-squares fit produced a regression equation y = 0.128x + 1.449, R 0.997. This used predict concentrations both artificially prepared lithium/saliva test solutions and hospitalized patients treated with Results agree well atomic absorption spectroscopy. Using reagent blank an equivalent amount as samples eliminated protein electrolyte absorbance interference. study supports continued exploration this method non-invasive point-of-care testing approach monitoring bipolar disorder.