Optimization of lard compound analysis using portable electronic nose based upon response surface methodology

Portable Electronic Nose (E-Nose) is a device that mimics human olfactory system and can be carried around for an “on-line” detection of lard in food. The objectives of this study wass to optimize process parameters for the determination of lard detection quantitatively. This study was important to increase the performance of the device in an efficient manner. The optimum conditions for the detection of lard were determined using Historical Data Design in Response Surface Methodology (RSM). This design was used to investigate the effects of the analytical conditions, namely weight (g), temperature (°C) and time (min). These parameters were found to give a positive effect on the sensor response, which plays an important role in the increment of the sensor response. While Analysis of Variance (ANOVA) shows that the selected quadratic model was significant with Fisher value of 40.77, as it adequately represented the data obtained. Moreover, regression analysis showed that 96% of the total variation was successfully explained by the models. Optimum process parameters generated by Design Expert 7.1.5 shown that 0.2g of lard is the minimum weight can be detected at 50°C for 3 minutes. Hence, this study had successfully optimized the process parameters using RSM for the presence of lard adulteration in food. © 2018, Malaysian Consumer and Family Economics Association. All rights reserved

Electrochemical sensory detection of Sus scrofa mtDNA for food adulteration using hybrid Ferrocenylnaphthalene Diimide intercalator as hybridization indicator

In this study, an electrochemical DNA biosensor was developed based on the fabrication of silicon nanowires/platinum nanoparticles (SiNWs/PtNPs) on a screen-printed carbon electrode (SPCE) for the detection of Sus scrofa mitochondrial DNA (mtDNA) in food utilizing a new hybrid indicator, ferrocenylnaphthalene diimide (FND). The morphology and elemental composition of the SiNWs/PtNPs-modified SPCE was analyzed by field emission scanning electron microscopy (FESEM) combined with energy dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) was used to study the electrical contact between the PtNPs and the screen-printed working electrode through SiNWs, while electrochemical impedance spectroscopy (EIS) was used to measure the charge transfer resistance of the modified electrode. The results clearly showed that the SiNWs/PtNPs were successfully coated onto the electrode and the effective surface area for the SiNWs/PtNPs-modified SPCE was increased 16.8 times as compared with that of the bare SPCE. Differential pulse voltammetry used for the detection of porcine DNA with FND as an intercalator confirmed its specific binding to the double-stranded DNA (dsDNA) sequences. The developed biosensor showed a selective response towards complementary target DNA and was able to distinguish non-complementary and mismatched DNA oligonucleotides. The SiNWs/PtNPs-modified SPCE that was fortified with DNA hybridization demonstrated good linearity in the range of 3 × 10−9 M to 3 × 10−5 M (R2 = 0.96) with a detection limit of 2.4 × 10−9 M. A cross-reactivity study against various types of meat and processed food showed good reliability for porcine samples

Enhanced Electrochemical Conductivity of Surface-Coated Gold Nanoparticles/Copper Nanowires onto Screen-Printed Gold Electrode

Electrochemical application has been widely used in the study of biosensors. Small biomolecules need a sensitive sensor, as the transducer that can relay the signal produced by biomolecule interactions. Therefore, we are improvising a sensor electrode to enhance electrochemical conductivity for the detection of small DNA molecule interaction. This work describes the enhanced electrochemical conductivity studies of copper nanowires/gold nanoparticles (CuNWs/AuNPs), using the screen-printed gold electrode (SPGE). The AuNPs were synthesized using the Turkevich method as well as characterized by the high-resolution transmission electron microscopy (HRTEM) and ultraviolet-visible (UV-Vis) analysis for the particle size and absorption nature, respectively. Further, the surface morphology and elemental analysis of a series of combinations of different ratios of CuNWs-AuNPs-modified SPGE were analyzed by field emission scanning electron microscopy (FESEM) combined with an energy dispersive X-ray (EDX). The results indicate that the nanocomposites of CuNWs-AuNPs have been randomly distributed and compacted on the surface of SPGE, with AuNPs filling the pores of CuNWs, thereby enhancing its electrochemical conductivity. The cyclic voltammetry (CV) method was used for the evaluation of SPGE performance, while the characterization of the electrochemical conductivity of the electrode modified with various concentrations of AuNPs, CuNWs, and different volumes of dithiopropionic acid (DTPA) has been conducted. Of the various parameters tested, the SPGE modified with a mixture of 5 mg/mL CuNWs and 0.25 mM AuNPs exhibited an efficient electrochemical conductivity of 20.3 µA. The effective surface area for the CuNWs-AuNPs-modified SPGE was enhanced by 2.3-fold compared with the unmodified SPGE, thereby conforming the presence of a large active biomolecule interaction area and enhanced electrochemical activity on the electrode surface, thus make it promising for biosensor application

Enhanced electrochemical conductivity of surface-coated gold nanoparticles/copper nanowires onto screen-printed gold electrode

Electrochemical application has been widely used in the study of biosensors. Small biomolecules need a sensitive sensor, as the transducer that can relay the signal produced by biomolecule interactions. Therefore, we are improvising a sensor electrode to enhance electrochemical conductivity for the detection of small DNA molecule interaction. This work describes the enhanced electrochemical conductivity studies of copper nanowires/gold nanoparticles (CuNWs/AuNPs), using the screen-printed gold electrode (SPGE). The AuNPs were synthesized using the Turkevich method as well as characterized by the high-resolution transmission electron microscopy (HRTEM) and ultraviolet-visible (UV-Vis) analysis for the particle size and absorption nature, respectively. Further, the surface morphology and elemental analysis of a series of combinations of different ratios of CuNWs-AuNPs-modified SPGE were analyzed by field emission scanning electron microscopy (FESEM) combined with an energy dispersive X-ray (EDX). The results indicate that the nanocomposites of CuNWs-AuNPs have been randomly distributed and compacted on the surface of SPGE, with AuNPs filling the pores of CuNWs, thereby enhancing its electrochemical conductivity. The cyclic voltammetry (CV) method was used for the evaluation of SPGE performance, while the characterization of the electrochemical conductivity of the electrode modified with various concentrations of AuNPs, CuNWs, and different volumes of dithiopropionic acid (DTPA) has been conducted. Of the various parameters tested, the SPGE modified with a mixture of 5 mg/mL CuNWs and 0.25 mM AuNPs exhibited an efficient electrochemical conductivity of 20.3 µA. The effective surface area for the CuNWs-AuNPs-modified SPGE was enhanced by 2.3-fold compared with the unmodified SPGE, thereby conforming the presence of a large active biomolecule interaction area and enhanced electrochemical activity on the electrode surface, thus make it promising for biosensor application