Rapid spectrophotometric method for the determination of fluorene

Abstract

Fluorene reacts rapidly with the sodium salt of 1,2-naphthoquinone-4-sulphonic acid in an alkaline dimethyl sulphoxide medium containing sodium methoxide and methanol to give a coloured product. The time necessary for this reaction was 30 s with continuous and thorough stirring. The intensity of the colour was measured spectrophotometrically at 655 nm following dilution with methanol. The apparent molar absorptivity is approximately 8.7 × 10³ l mol^–1 cm^–1, and Beer's law is obeyed over the concentration range 1–16 µg ml^–1 of fluorene. The colour was stable if the product was kept in a tightly stoppered flask for at least 1.5 h in the presence of small amounts of 2,6-di-tert-butyl-4-methylphenol.