scholarly journals Detection of Triclosan in Tuned Solutions by pH and Ionic Strength Using PAH/PAZO Thin Films

Proceedings ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 25
Author(s):  
Paulo M. Zagalo ◽  
Cátia Magro ◽  
João Pereira-da-Silva ◽  
Benachir Bouchikhi ◽  
Nezha El Bari ◽  
...  
Keyword(s):  
Thin Films ◽  
Ionic Strength ◽  
Sodium Salt ◽  
Personal Care Products ◽  
Electronic Tongue ◽  
Layer By Layer ◽  
Personal Care ◽  
Electrical Parameters ◽  
Adsorbed Amount ◽  
Lbl Films

The electronic tongue concept based on layer-by-layer (LbL) films can be used to the detection in water of triclosan (TCS), a pernicious molecule used in personal care products and widely released in the environment. In this work, we analyzed the adsorption of TCS on poly(allylaminehydrochloride) (PAH) and poly[1-[4-(3-carboxy-4hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) layers of PAH/PAZO LbL films. We demonstrate that the adsorbed amount is strongly dependent of pH, the efficiency of adsorption of TCS on PAH layer is higher, and, when PAZO is the outmost layer, the electrical parameters can discriminate the ionic strength on solutions of TCS.

scholarly journals Polyelectrolyte Based Sensors as Key to Achieve Quantitative Electronic Tongues: Detection of Triclosan on Aqueous Environmental Matrices

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 640
Author(s):  
Cátia Magro ◽  
Paulo Zagalo ◽  
João Pereira-da-Silva ◽  
Eduardo Pires Mateus ◽  
Alexandra Branco Ribeiro ◽  
...  
Keyword(s):  
Continuous Monitoring ◽  
Mineral Water ◽  
Electronic Tongue ◽  
Principal Component ◽  
Electrical Impedance Spectroscopy ◽  
Layer By Layer ◽  
Environmental Matrices ◽  
Film Stability ◽  
Lbl Films ◽  
Water And Wastewater

Triclosan (TCS) is a bacteriostatic used in household items that promotes antimicrobial resistance and endocrine disruption effects both to humans and biota, raising health concerns. In this sense, new devices for its continuous monitoring in complex matrices are needed. In this work, sensors, based on polyelectrolyte layer-by-layer (LbL) films prepared onto gold interdigitated electrodes (IDE), were studied. An electronic tongue array, composed of (polyethyleneimine (PEI)/polysodium 4-styrenesulfonate (PSS))5 and (poly(allylamine hydrochloride/graphene oxide)5 LbL films together with gold IDE without coating were used to detect TCS concentrations (10−15–10−5 M). Electrical impedance spectroscopy was used as means of transduction and the obtained data was analyzed by principal component analysis (PCA). The electronic tongue was tested in deionized water, mineral water and wastewater matrices showing its ability to (1) distinguish between TCS doped and non-doped solutions and (2) sort out the TCS range of concentrations. Regarding film stability, strong polyelectrolytes, as (PEI/PSS)n, presented more firmness and no significant desorption when immersed in wastewater. Finally, the PCA data of gold IDE and (PEI/PSS)5 sensors, for the mineral water and wastewater matrices, respectively, showed the ability to distinguish both matrices. A sensitivity value of 0.19 ± 0.02 per decade to TCS concentration and a resolution of 0.13 pM were found through the PCA second principal component.

scholarly journals Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Luiza A. Mercante ◽  
Vanessa P. Scagion ◽  
Adriana Pavinatto ◽  
Rafaela C. Sanfelice ◽  
Luiz H. C. Mattoso ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Chemical Sensors ◽  
Film Growth ◽  
Electronic Tongue ◽  
Principal Component ◽  
Inorganic Materials ◽  
Milk Analysis ◽  
Layer By Layer ◽  
Nanostructured Films ◽  
Lbl Films

The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride) (Au@PAH NPs), as well as the capability of this material to form multilayer Layer-by-Layer (LbL) nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc). Film growth was monitored by UV-Vis absorption spectroscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA), revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment.

scholarly journals Voltammetric Detection of Caffeine in Beverages at Nafion/Graphite Nanoplatelets Layer-by-Layer Films

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 221 ◽  
Author(s):  
Sandra Hernandez-Aldave ◽  
Afshin Tarat ◽  
James D. McGettrick ◽  
Paolo Bertoncello
Keyword(s):  
Thin Films ◽  
Hydrogen Bonding ◽  
Hydrophobic Interactions ◽  
Carbon Electrodes ◽  
Layer By Layer ◽  
Graphite Nanoplatelets ◽  
Glassy Carbon Electrodes ◽  
X Ray ◽  
Voltammetric Detection ◽  
Lbl Films

We report for the first time a procedure in which Nafion/Graphite nanoplatelets (GNPs) thin films are fabricated using a modified layer-by-layer (LbL) method. The method consists of dipping a substrate (quartz and/or glassy carbon electrodes) into a composite solution made of Nafion and GNPs dissolved together in ethanol, followed by washing steps in water. This procedure allowed the fabrication of multilayer films of (Nafion/GNPs)n by means of hydrogen bonding and hydrophobic‒hydrophobic interactions between Nafion, GNPs, and the corresponding solid substrate. The average thickness of each layer evaluated using profilometer corresponds to ca. 50 nm. The as-prepared Nafion/GNPs LbL films were characterized using various spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), FTIR, and optical microscopy. This characterization highlights the presence of oxygen functionalities that support a mechanism of self-assembly via hydrogen bonding interactions, along with hydrophobic interactions between the carbon groups of GNPs and the Teflon-like (carbon‒fluorine backbone) of Nafion. We showed that Nafion/GNPs LbL films can be deposited onto glassy carbon electrodes and utilized for the voltammetric detection of caffeine in beverages. The results showed that Nafion/GNPs LbL films can achieve a limit of detection for caffeine (LoD) of 0.032 μM and linear range between 20‒250 μM using differential pulse voltammetry, whereas, using cyclic voltammetry LoD and linear range were found to be 24 μM and 50‒5000 μM, respectively. Voltammetric detection of caffeine in beverages showed good agreement between the values found experimentally and those reported by the beverage producers. The values found are also in agreement with those obtained using a standard spectrophotometric method. The proposed method is appealing because it allows the fabrication of Nafion/GNPs thin films in a simple fashion using a single-step procedure, rather than using composite solutions with opposite electrostatic charge, and also allows the detection of caffeine in beverages without any pre-treatment or dilution of the real samples. The proposed method is characterized by a fast response time without apparent interference, and the results were competitive with those obtained with other materials reported in the literature.

scholarly journals Triclosan Detection in Aqueous Environmental Matrices by Thin-Films Sensors

Proceedings ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 24
Author(s):  
Cátia Costa Magro ◽  
Paulo Morgado Zagalo ◽  
João Pereira-da-Silva ◽  
Eduardo Pires Mateus ◽  
Alexandra Branco Ribeiro ◽  
...  
Keyword(s):  
Thin Films ◽  
Deionized Water ◽  
Water Bodies ◽  
Layer By Layer ◽  
Impedance Spectra ◽  
Environmental Matrices ◽  
Interdigitated Electrodes ◽  
Lbl Films ◽  
Aqueous Matrices

Triclosan (TCS), a bacteriostatic detected in water bodies, have inauspicious effects in human and biota. Consequently, there is a critical need of monitoring these type of compounds in aqueous matrices. In this sense, sensors, based on polyethyleneimine and polysodium 4-styrenesulfonate layer-by-layer thin-films adsorbed on supports with gold interdigitated electrodes deposited, were developed. The aim was analyze the sensitivity of discrimination of TCS (10−15 M to 10−5 M) in deionized water, Luso® and in an effluent, by measuring the impedance spectra. LbL films can distinguish TCS concentrations in EF, while in LW was achieved an acceptable sensibility when interdigitated electrodes without films were used.

Effect of Sales Promotions on Consumer Purchase Behavior with Reference to Personal Care Products

2012 ◽  
Vol 2 (10) ◽  
pp. 1-2
Author(s):  
D. Muthukrishnaveni D. Muthukrishnaveni ◽  
◽  
Dr. D. Muruganandam Dr. D. Muruganandam
Keyword(s):  
Personal Care Products ◽  
Purchase Behavior ◽  
Personal Care ◽  
Sales Promotions
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