Determination Of Ascorbic Acid In Foods Research Articles

Food-borne melanoidin based peroxidase mimic for the precise detection of total antioxidant capacity

Drawing on the structure of the natural horseradish peroxidase (HRP) active site, in this study, food-borne Melanoidin and Fe3+ were used to construct a peroxide mimic enzyme, which possessed excellent peroxidase (POD)-like activity with the Km values of 0.088 mM and 0.358 mM toward 3,3′,5,5′-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2), respectively. Given the good POD-like activity of Melanoidin/Fe3+, a convenient, selective, and sensitive method for the determination of ascorbic acid (AA) was defined. The method covered the 10–100 μM AA concentration range with a 1.19 μM detection limit. With favorable anti-interference and strong stability, Melanoidin/Fe3+ was successfully applied to the determination of AA in foods and medicines. The high activity of Melanoidin/Fe3+ provides a new strategy for designing high-performance nanozymes, which has great potential in exogenous dietary and healthcare applications.

Amperometric Determination of Ascorbic Acid in Real Samples Using a Disposable Screen-Printed Electrode Modified with Electrografted o-Aminophenol Film

Ascorbic acid (AA) is an antioxidant considered to play a crucial role in human health. Therefore, diverse methods for the determination of AA in foods have been developed, most of them time-consuming and requiring costly instrumentation. A simple and sensitive method for the quantification of AA in fresh fruits and vegetables and commercial juices using an amperometric sensor is presented on the basis of disposable screen-printed carbon electrodes (SPEs) modified with an o-aminophenol (o-AP) film selective for the detection of AA. The sensor exhibited a linear response for AA from 2-20 microM, with a correlation coefficient r2 = 0.998 and a limit of detection of 0.86 microM. Common possible interferents of the sample matrices were tested, and results showed high selectivity of the o-AP SPEs toward AA. The sensor exhibited an excellent reproducibility (RSD% = 1.98, n = 8) and surface stability. The method was validated by a comparison to a reference method, and excellent correlation is obtained.

Use of an amino acid in the mobile phase for the determination of ascorbic acid in food by high-performance liquid chromatography with electrochemical detection

The possibility of using monosodium l-glutamate (MSG) (20 m M MSG, pH 2.1) in the mobile phase for the determination of ascorbic acid (AA) in foods by high-performance liquid chromatography (HPLC) with electrochemical detection was examined. The hydrodynamic voltammogram of AA and the background current were also examined. The applied potential was set at 400 mV versus an Ag/AgCl reference electrode. It was demonstrated that MSG was a useful mobile phase for the determination of AA in foods. This paper also examines the stability of AA under various conditions in order to optimize HPLC conditions and the pre-run sample stabilization. The proposed method is simple, rapid (analysis time: ∼6 min), sensitive (detection limit: ∼0.1 ng per injection (5 μl) at a signal-to-noise ratio of 3), highly selective and reproducible (relative standard deviation: ∼2.5%, n=7). The calibration graph of AA was linear in the range 0.1–50 ng per injection (5 μl). Recovery of AA was over 90% by the standard addition method.