Second order derivative spectrophotometric method for determination of vitamin C content in fruits, vegetables and fruit juices

Abstract

A second-order derivative UV spectrophotometric method for determination of vitamin C [ascorbic acid (AA)] content in a variety of natural samples is described. The method is based on the measurement of a peak–baseline amplitude in the second derivative of the AA spectrum at 267.5 nm. The following corresponding regression equation was obtained within the concentration range 2×10-5 to 1×10-4 M AA (3.5–17.6 μg/cm3 AA) in 1.0 M HCl solution: 2D267.5=2.420×104 c+0.025; the correlation coefficient was 0.9993 and the detection limit 4.2×10-6 M. The results obtained by analysing 21 different species of fruits, vegetables and juices indicated a possibility for a more extensive application of the proposed method. This method is rapid, simple and requires no pretreatment of the analysed material, which makes it suitable for routine analyses. The reliability of the method was confirmed by comparative determinations with the generally accepted 2,6-dichloroindophenol method.