Micro determination of ascorbic acid using methyl viologen.
A new simple and sensitive analytical spectrophotometric method is developed for the determination of ascorbic acid reduces methyl viologen to form a stable blue coloured free radical ion. This method has a sensitivity and lower limit detection of 0.1mugml(-1) of ascorbic acid (0.1ppm) which is comparable to the flow injection analysis reported earlier. Beer's law is obeyed over the concentration range of 1.0-10mugml(-1) of ascorbic acid per 10ml of the final solution (0.1-1.0mugml(-1)) at 600nm. The molar absorptivity and Sandell's sensitivity were found to be 1.5x10(5)+/-100lmol(-1)cm(-1) and 0.001mugcm(-2), respectively. The method has been applied to the determination of ascorbic acid in food, pharmaceuticals and biological samples.
Janghel
E K
EK
Chhattisgarh Institute of Technology, Near Parri Nala, G.E. Road, Rajnangaon, Chhattisgarh, India.
Gupta
V K
VK
Rai
M K
MK
Rai
J K
JK