Fast Determination of Antioxidant Capacity of Food Samples Using Continuous Amperometric Detection on Polyester Screen‐printed Graphitic Electrodes

Abstract

The determination of antioxidant capacity of food samples using disposable polyester screen‐printed graphitic macroelectrodes (SPGE) coupled with a batch‐injection cell based on the measurement of the consumption of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH.) is reported. The SPGEs are organic‐resistant electrodes and thus compatible with food samples and organic solvents used to dissolve DPPH.. A micropipette controlled the release (193 μL s−1) of sample (150 μL) upon the sensor/working electrode immersed in electrolyte (1 : 1 ethanol/methanol containing 0.05 mol L−1 LiCl). The first demonstration of this protocol was devoted to the analysis of edible oils. The remaining DPPH. was amperometrically detected at +0.1 V (vs. pseudo AgCl). The antioxidant capacity (percentage of DPPH. scavenging and mg equivalent of tocopherol) was obtained using the proposed and spectrophotometric methods. The results were in agreement according to t‐test (confidence level of 95 %). The method is precise (RSD=2.3 %, n=12), fast (180 h−1), presents low detection limit of DPPH. (1 μmol L−1), and allows on‐site analysis. Moreover, the proposed method can be extended to the analysis of antioxidant capacity of other samples of agricultural and food interests.

3D‐printed Portable Platform for Mechanized Handling and Injection of Microvolumes Coupled to Electrochemical Detection

“…The 3D‐printed system has an injection procedure similar to BIA systems ; however, solution handling conditions can be easily performed . As a proof of concept, the possibility of determination of the antioxidant capacity based on the percentage of DPPH scavenging was demonstrated . The DPPH radical is an electroactive compound and its consumption by antioxidants (at a fixed reaction time) can be measured by electrochemical detection.…”

“…As a proof of concept, the possibility of determination of the antioxidant capacity based on the percentage of DPPH scavenging was demonstrated . The DPPH radical is an electroactive compound and its consumption by antioxidants (at a fixed reaction time) can be measured by electrochemical detection. Figure presents the amperometric peaks for triplicate injections of 87 μmol L −1 DPPH standard solution in the absence (a) and in the presence (b–g) of increasing concentrations of BHT (5, 10, 15, 20, 25 and 30 μmol L −1 ).…”

An Overview of Recent Electroanalytical Applications Utilizing Screen‐Printed Electrodes Within Flow Systems

“…Polyester SPGE 0.06 0.08 0.05 4 [29] Pb 2 + Cu 2 + Hg(II) Biodiesel AuSPE 0.005 0.008 0.003 30 [82] Ciprofloxacin PF SPE modified with MWCNT 0.06 130 [83] Sildenafil PF SPE modified with GR 0.05 115 [84] Hg 2 + Biodiesel AuSPE 0.02 NR [85] Pb 2 + Aviation Fuel AuSPE 0.004 NR [86] Omeprazole PF SPE modified with MWCNT 0.009 120 [87] Corrosion inhibitors Ethanol, seawater and mineral oil SPGE 0.3 180 [88] Levamisole Levothyroxine PF SPCE or SPE modified with MWCNT Organic-resistant SPGE 0.14 0.10 170 150 [89] Nitrite Uric Acid Saliva, urine, and blood SPE modified with MWCNT 0.06 0.05 160 [90] Antioxidant capacity (DPPH) Edible oil Polyester SPGE 1.0 180 [91] [a] AF: analytical frequency (injections h À 1 ); LOD: limit of detection; PF: pharmaceutical formulation; PB: Prussian blue; GR: graphene; WE: working electrode. and selectivity) combine more with the characteristics of BIA systems.…”

“…The attractive features of the BIASPE system were also explored for the on-site determination of carbendazim, catechol and hydroquinone in tap water, [20] metals (Zn 2 + , Cd 2 + , Pb 2 + , Cu 2 + , and Hg 2 + ) in biodiesel samples, [85] glucose in artificial serum sample, [21] antioxidant 2,6-di-tert-butylphenol (2, in biodiesel and jet-fuel using hydro-organic media as the supporting electrolyte, [26] lead in aviation fuel samples, [86] omeprazole in pharmaceutical samples, [87] corrosion inhibitors (2,5-dimercapto-1,3,5-thiadiazole) in fuel ethanol, seawater and mineral oil samples, [88] levamisole and sodium levothyroxine in pharmaceutical samples, [89] nitrite and uric acid in biological fluids (urine, plasma, saliva, and serum), [90] antioxidant capacity of edible oil samples, [91] benzocaine and tricaine in fish fillets, [92] and a robust electroanalytical system for detection of UVinduced DNA degradation. [93] Recently, Mendonça et al [94] reported a low-cost mechanized system fabricated using fused deposition modelling 3D-printing technology to perform injections on an electrochemical cell in wall-jet configuration (similar to a common BIA cell).…”

Batch‐injection Amperometric Analysis on Screen‐printed Electrodes: Analytical System for High‐throughput Determination of Pharmaceutical Molecules

“…This system operating under amperometric detection can provide high sample throughput (>150 h −1 ) keeping high precision of injection . More recently the applicability of the BIA‐SPE system was enhanced by the possibility of using SPEs that are resistant to organic solvents, which enabled the analysis of liquid fuels and oils .…”