Detection and Quantitative Analysis for 2-Thiobarbituric Acid Utilizing Uv-Visible Spectrophotometer

The thiobarbiturates differ from other barbiturates in having a sulfur atom in place of the carbonyl oxygen at the C-2 position. The drug 2-thiobarbituric acid was found to be sufficiently soluble in 95% ethanol and 5% water for highly sensitive detection and assay. Analytical samples, including standards, were studied at 320 nanometer wavelength with background absorbance of the solvent correctly determined and subtracted from prepared specimens in one centimeter glass cuvettes. An ultraviolet-visible instrument Spectronic 21D was found to be suitable for this assay. The molar extinction coefficient was determined at 320nm by dissolving a known amount of 2-thiobarbituric acid into 95% ethanol and 5% water and found to be 414.9 Liter/(cm)(mole). An absorbance spectrum for 2-thiobarbituric acid is presented. The standard curve utilized a range from 0.00006267 molar to 0.004201 molar. The lowest concentration assayed was0.01313 grams per liter (1.313E-05 grams per milliliter or 13.13 micrograms per milliliter) with the highest concentration at 0.6056 grams per liter (6.056E-04 grams per milliliter or 605.6 micrograms per milliliter). This method was found to be consistent and highly sensitive.