Indirect determination of ascorbic acid (vitamin C) by spectrophotometric method

Abstract

A novel spectrophotometric method is described. The procedure involves the use of Cu (II) as vitamin C oxidant. After completion of oxidation reaction, excess of Cu (II) is determined by complexation with alizarin red s (ARS). Thiocyanate ion is used as stabilising agent for Cu (I) which is the product of oxidation reaction. This method is used for determination of vitamin C in fruits and pharmaceutical products. Linearity was found to be perfect in the range 3.5 · 10 )6 -4.8 · 10 )5 m (0.6-8.2 ppm). The detection limit and relative standard deviation of method are 2.0 · 10 )6 m (0.35 ppm) and 1.03%, respectively. The proposed method is simple, safe, inexpensive and rapid.

Fabrication of carboxymethyl chitosan/oxidized carboxymethyl cellulose composite film and its assessment for coating preservation of strawberry

“…The hardness of strawberry was measured using a GY‐1 hardness tester (Beijing Times Innovation Technology Co., Ltd, Beijing, China). The contents of organic acids, soluble solids, reducing sugars, and Vc were determined by titration (Xu & Wu, 2021), Abbe refractometry (Kang et al., 2021), 3,5‐dinitrosalicylic acid (DNS) colorimetry (Chua et al., 2012), and ultraviolet spectrophotometry (Nejati‐Yazdinejad, 2007). The incidence of decay of the strawberries was calculated as follows (Xu & Wu, 2021): $$$$\begin{eqnarray}Decay\ rate\ &=& \frac{{the\ number\ of\ rotting\ strawberries}}{{total\ number\ of\ strawberries}}\ \nonumber\\ &&\times 100\% \end{eqnarray}$$$$…”

A highly sensitive switch-on spectrofluorometric method for determination of ascorbic acid using a selective eco-friendly approach

“…The reported spectrofluorometric methods employed fluorescent dyes, or quantum dots as shown in Table 5 . These methods suffered from a number of limitations such as the complicated procedures [14] , [39] , [40] , the long reaction time [15] , the high temperature required [18] , [41] , [42] and the necessity for catalyst addition. Compared with these reported methods, our proposed method is easier, faster, and does not require heating or catalysis due to the instantaneous reaction and the high yield.…”

Determination of trace amount of some drugs as in its pure form and in its Pharmaceutical Preparations by using different spectroscopic methods

“…Atomic absorption spectroscopy (AAS) is defined as an analytical method for determining metals, semi-metals and some non-metals with trace concentrations in a wide variety of samples and depends on the ability of free, neutral atoms to absorb a resonant beam of that element when it is passed through atomic vapour (45,46,47).…”