Spectrophotometric determination of yeast RNA with neutral red

The interaction of neutral red (NR) with yeast RNA (yRNA) was studied by UV-Vis spectrophotometry to develop a simple spectrophotometric method for the determination yRNA. NR exhibited a maximum absorption peak at 528 nm in a Britton-Robinson (B-R) buffer solution of pH 4.0. After the addition of yRNA into NR solution, the absorbance value was greatly decreased and no new absorption peaks appeared. The interaction conditions such as the buffer pH, reaction time, etc. were carefully studied. Under the optimal conditions the decrease in absorbance value was proportional to the yRNA concentration in the range from 0.2 to 20.0 mg L-1 when 8.0 × 10-5 M NR was employed. The detection limit was calculated as 0.78 mg L-1 (3σ) and three synthetic samples were determined satisfactorily. A binding ratio of NR to yRNA was found to be 1:1 by the molar ratio method. KEY WORDS: Neutral red, Yeast RNA, Interaction, UV-Vis spectrophotometry Bull. Chem. Soc. Ethiop. 2008, 22(3), 441-444.