Abstract:

A simple decolouring spectrophotometric method for the determination of methanol was developed in this work. A russety product can be formed by the reaction between Lysine(Lys) and sodium 1,2-naphthoquinone-4-sulfonate(NQS) in an alkaline solution. When methanol was added to the solution, the system involves decolouring process. Beer′s law is held in a range of methanol concentration of 0.050~7.61 g/L at a maximal decolouring wavelength of 559 nm. The equation of linear regression is A=-0.005 17-0.086 79c(g/L), with a linearly correlation coefficient of 0.999 6. The detection limit of methanol is 49.5 mg/L(3s/k) and the recovery rate is in a range of 99.1%~102.6%. Analytical results obtained with this method are satisfactory.

Key words: spectrophotometry, methanol, L-lysine, Sodium naphthoquinonesulfonate