scholarly journals Development of a Novel Electrochemical Biosensor Based on Carbon Nanofibers–Gold Nanoparticles–Tyrosinase for the Detection of Ferulic Acid in Cosmetics

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6724
Author(s):  
Alexandra Virginia Bounegru ◽  
Constantin Apetrei
Keyword(s):  
Gold Nanoparticles ◽  
Ferulic Acid ◽  
Carbon Nanofibers ◽  
Electrochemical Biosensor ◽  
Detection Threshold ◽  
Infrared Range ◽  
Spectrometric Method ◽  
Sensitivity And Selectivity ◽  
Electroanalytical Method ◽  
Higher Sensitivity

The present paper deals with the electrochemical behavior of three types of sensors based on modified screen-printed electrodes (SPEs): a sensor based on carbon nanofibers (CNF/SPE), a sensor based on nanofibers of carbon modified with gold nanoparticles (CNF-GNP/SPE) and a biosensor based on nanofibers of carbon modified with gold nanoparticles and tyrosinase (CNF-GNP-Ty/SPE). To prepare the biosensor, the tyrosinase (Ty) was immobilized on the surface of the electrode already modified with carbon nanofibers and gold nanoparticles, by the drop-and-dry technique. The electrochemical properties of the three electrodes were studied by cyclic voltammetry in electroactive solutions, and the position and shape of the active redox peaks are according to the nature of the materials modifying the electrodes. In the case of ferulic acid, a series of characteristic peaks were observed, the processes being more intense for the biosensor, with the higher sensitivity and selectivity being due to the immobilization of tyrosinase, a specific enzyme for phenolic compounds. The calibration curve was subsequently created using CNF-GNP-Ty/SPE in ferulic acid solutions of various concentrations in the range 0.1–129.6 μM. This new biosensor allowed low values of the detection threshold and quantification limit, 2.89 × 10−9 mol·L−1 and 9.64 × 10−9 mol·L−1, respectively, which shows that the electroanalytical method is feasible for quantifying ferulic acid in real samples. The ferulic acid was quantitatively determined in three cosmetic products by means of the CNF-GNP-Ty/SPE biosensor. The results obtained were validated by means of the spectrometric method in the infrared range, the differences between the values of the ferulic acid concentrations obtained by the two methods being under 5%.

scholarly journals Development of a Novel Electrochemical Biosensor Based on Carbon Nanofibers–Cobalt Phthalocyanine–Laccase for the Detection of p-Coumaric Acid in Phytoproducts

2021 ◽  
Vol 22 (17) ◽  
pp. 9302
Author(s):  
Alexandra Virginia Bounegru ◽  
Constantin Apetrei
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Nanofibers ◽  
Square Wave Voltammetry ◽  
Electrochemical Biosensor ◽  
Spectrometric Method ◽  
Cobalt Phthalocyanine ◽  
Coumaric Acid ◽  
Wave Voltammetry ◽  
Enzymatic Biosensor ◽  
The One

The present paper developed a new enzymatic biosensor whose support is a screen-printed electrode based on carbon nanofibers modified with cobalt phthalocyanine and laccase (CNF-CoPc-Lac/SPE) to determine the p-coumaric acid (PCA) content by cyclic voltammetry and square wave voltammetry. Sensor modification was achieved by the casting and cross-linking technique, using glutaraldehyde as a reticulation agent. The biosensor’s response showed the PCA redox processes in a very stable and sensitive manner. The calibration curve was developed for the concentration range of p-coumaric acid of 0.1–202.5 μM, using cyclic voltammetry and chronoamperometry. The biosensor yielded optimal results for the linearity range 0.4–6.4 μM and stood out by low LOD and LOQ values, i.e., 4.83 × 10−7 M and 1.61 × 10−6 M, respectively. PCA was successfully determined in three phytoproducts of complex composition. The results obtained by the voltammetric method were compared to the ones obtained by the FTIR method. The amount of p-coumaric acid determined by means of CNF-CoPc-Lac/SPE was close to the one obtained by the standard spectrometric method.

Simultaneous Determination of Alogliptin, Linagliptin, Saxagliptin, and Sitagliptin in Bulk Drug and Formulation by UPLC Q-TOF-MS

2020 ◽  
Vol 17 (1) ◽  
pp. 95-105
Author(s):  
Ramji Rathod ◽  
Faraat Ali ◽  
Amrish Chandra ◽  
Robin Kumar ◽  
Meenakshi Dahiya ◽  
...  
Keyword(s):  
Internal Standard ◽  
Gradient Elution ◽  
Ultra Performance Liquid Chromatography ◽  
Pharmaceutical Dosage Forms ◽  
Sensitivity And Selectivity ◽  
The Mean ◽  
Bulk Drug ◽  
Positive Ion ◽  
Higher Sensitivity

Background: A simple and sensitive Ultra Performance Liquid Chromatography-Mass Spectrometry method was developed and validated to measure the concentrations of Alogliptin (ALO), Linagliptin (LIN), Saxagliptin (SAX), and Sitagliptin (SIT) using Pioglitazone (PIO) as an internal standard. Methods: Chromatographic separation of six gliptins was achieved on a C-18 column (100×2.1 mm, 2.7 μm) using a mobile phase consisting of formic acid in water, 0.1%v/v: acetonitrile in gradient elution. Electrospray ionization (ESI) source was operated in the positive ion mode. Targeted MS/MS mode on a QTOF MS was used to quantify the drug utilizing the transitions of 340.1(m/z), 473.2 (m/z), 316.2 (m/z), 408.1 (m/z), and 357.1 (m/z) for ALO, LIN, SAX, SIT and PIO respectively. Results: As per ICH Q2R1 guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear over the concentration ranges of 1516.0-4548.1 ng mL-1, 519.8- 1559.4 ng mL-1, 1531.4-4594.3 ng mL-1and 1519.6-4558.8 ng mL-1 for ALO, LIN, SAX and SIT respectively. Precision and accuracy results were within the acceptable limits. The mean recovery was found to be 98.8 _ 0.76 % (GEM), 102.2 _ 1.59 % (LIN), 95.3 _ 2.74 % (SAX) and 99.2 _ 1.75 % (SIT) respectively. Conclusions: The optimized validated UPLC QTOF-MS/MS method offered the advantage of shorter analytical times and higher sensitivity and selectivity. The optimized method is suitable for application in quantitative analysis of pharmaceutical dosage forms for QC laboratory.

A highly sensitive electrochemical microRNA-21 biosensor based on intercalating methylene blue signal amplification and a highly dispersed gold nanoparticles/graphene/polypyrrole composite

The Analyst ◽  
2021 ◽  
Vol 146 (8) ◽  
pp. 2679-2688
Author(s):  
Chammari Pothipor ◽  
Noppadol Aroonyadet ◽  
Suwussa Bamrungsap ◽  
Jaroon Jakmunee ◽  
Kontad Ounnunkad
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Signal Amplification ◽  
Electrochemical Biosensor ◽  
Highly Sensitive ◽  
Highly Dispersed ◽  
Polypyrrole Composite ◽  
Amplification Strategy ◽  
Dispersed Gold ◽  
Potential Tool

An ultrasensitive electrochemical biosensor based on a gold nanoparticles/graphene/polypyrrole composite modified electrode and a signal amplification strategy employing methylene blue is developed as a potential tool for the detection of miRNA-21.

scholarly journals A simple and sensitive sensor for silver ions based on unmodified gold nanoparticles by using dynamic light scattering techniques

2017 ◽  
Vol 95 (12) ◽  
pp. 1267-1272 ◽  
Author(s):  
Zhiyou Xiao ◽  
Anjiang Tang ◽  
Hongsheng Huang ◽  
Ze Wang
Keyword(s):  
Gold Nanoparticles ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
High Sensitivity ◽  
Silver Ions ◽  
Hydrodynamic Diameter ◽  
Optimum Conditions ◽  
Sensitivity And Selectivity ◽  
Sensitive Sensor ◽  
Average Hydrodynamic Diameter

A simple and sensitive assay for Ag+ was developed with unmodified gold nanoparticles (AuNPs) by using dynamic light scattering techniques. Ag+ could induce the oligonucleotide (5′-ATC ACT ATA TCA TAT ACT CAT-3′) to change from a single-stranded structure to a double-stranded structure and desorb from the surface of AuNPs, which triggered the aggregation of AuNPs in the salt solution. The average hydrodynamic diameter of aggregated AuNPs could be detected by using dynamic light scattering techniques. Under the optimum conditions, the average hydrodynamic diameter of AuNPs is proportional to the concentration of Ag+ within the range of 13.3–100.0 nmol/L, with a detection limit of 3.2 nmol/L. The method is easy to operate and has low sample consumption, high sensitivity and selectivity.

The confinement effect on the activity of Au NPs in polyol oxidation

2016 ◽  
Vol 6 (3) ◽  
pp. 598-601 ◽  
Author(s):  
Alberto Villa ◽  
Di Wang ◽  
Carine E. Chan-Thaw ◽  
Sebastiano Campisi ◽  
Gabriel M. Veith ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Carbon Nanofibers ◽  
Confinement Effect ◽  
Au Nps ◽  
The One

We demonstrate a confinement effect where gold nanoparticles trapped within N-functionalized carbon nanofibers (N-CNFs) are more active for polyol oxidation and promote selectivity towards di-acid products, whereas AuNPs trapped on the surface produce as a major by-product the one derived from C–C cleavage.

Enhanced Sensitivity and Selectivity of Chemosensor for Malonate by Anchoring on Gold Nanoparticles

2011 ◽  
Vol 29 (3) ◽  
pp. 531-538 ◽  
Author(s):  
Yanyun Liu ◽  
Yun Liu ◽  
Zhongshi Liang ◽  
Xiangyang Li ◽  
Shunying Liu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Enhanced Sensitivity ◽  
Sensitivity And Selectivity

Modularization of three-dimensional gold nanoparticles/ferrocene/liposome cluster for electrochemical biosensor

2019 ◽  
Vol 124-125 ◽  
pp. 115-121 ◽  
Author(s):  
Tingjun Chen ◽  
Anzhi Sheng ◽  
Yong Hu ◽  
Dongsheng Mao ◽  
Limin Ning ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Electrochemical Biosensor ◽  
Three Dimensional
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