Determination of One of Quinoxaline N-oxides by Spectrophotometry
MA Jing-zhong *, JIANG Hong (Science College, Central China Agricultural University, Wuhan, 430070)
N,N′-Dioxide-2-methylquinoxaline is colored with two methods : (1) In the solution of NaOH. The solution of the compound isomerizes fully into blue compound in a 70~80℃ water bath within 50 mins. The regression equation obtained by spectrophotometric determination is:A=0 00883c+0.0145,r=0.990. Beer's law is obeyed by the concentration range of 4.44~220×10 -3 mg/mL. (2) In the solution of NaHSO 3 / H 2SO 4. The solution of the compound is reduced into light yellow-green or green compound in room temperature within 20~30 mins. The regression equation obtained is: A=0.000774c-0.002,r=0.999. Beer's law is obeyed with the concentration range of 1.1~777×10 -3 mg/mL. This study supplies a better method to quantitative analysis of the medium compound of drug.