Detection of bisphenol S via screen-printed electrodes

Screen-printed electrodes are economical, easy-to-use electrochemical sensors that can be used for in-situ real-time monitoring of toxic substances. This work represents a comparison of two SPEs electrodes for the detection of bisphenol S (BPS). BPS is an endocrine interrupts the hormonal system in humans and shows a genotoxic, cytotoxic and cancerpromoting effect. Fast and reliable detection of bisphenols is very important. Chromatographic and spectroscopic techniques are the most used methods for the detection of bisphenols, however they are expensive, complicated and consume a lot of time. On the other hand, electrochemical sensors are promising since they are fast, reliable and simple methods for in-situ measuring. In the present work the detection of BPS was performed via screen-printed electrodes with carbon nanoparticles and carbon single-wall nanotube working electrodes. Determination of BPS was carried out by cyclic voltammetry (CV) anddifferential puls voltammetry (DPV). The influence of different concentrations of BPS, scan rate and influencing BPA on detection were studied. Screen-printed electrodes showed very good electrochemical activity, sensitivity and repeatability. Screen-printed electrodes enable the miniaturization of sensors elements, using smaller volumes of samples, rapid and low cost detection without generating dangerous waste

Electrochemical sensors for detection of bisphenols

The endocrine-disrupting chemicals (EDCs) are chemicals of very high concern that have hazards with serious consequences on human health. It influences on development of metabolic disorders, reproduction and respiratory problems. They can be found in our everyday life, from food, and personal care products to medical devices, dental products, special lenses and baby drink cans. Among several EDCs, banned Bisphenol A (BPA) and his substitute Bisphenol S (BPS) have attracted attention due to high usage during the manufacturing process for water and food packaging, in the production of epoxy resins, lacquer coating and can even be found in receipt. Due to that, there is a need for the fast, reliable and commercial detection of Bisphenols in everyday life. The gold standard for the detection of Bisphenols is chromatography and enzyme-linked immunosorbent assay, expensive and robust methods. Electrochemical sensors are a new approach to the detection of EDCs in very small quantities in complex environments. The aim of this research was to study commercial screen-printed electrodes (SPEs) as receptor elements in electrochemical sensors for the detection of BPA and BPS. Scanning electron microscopic (SEM) and Fourier transform infrared spectroscopy (FT-IR) were employed for examining the surface of the SPEs working electrodes. SPE electrodes showed very good voltammetric responses toward BPA and BPS oxidation with linear ranges between 0.5 and 50.0 μM and lower limits of detection of 0.15 μM and 0.37 μM, respectively

Electrochemical sensor for detection bisphenols in thermal paper

The substances of very high concern (SVHCs) can be found in a wide range of consumer products. These substances can negatively influence human health depending on the route of exposure, exposure time and duration, amount of intake the substance by body and other factors. Increased number of carcinoma, sterility, diabetes can be due to the contact with SVHCs in our everyday life. Bisphenol A (BPA) is one of the most commercialized SVHC chemicals and is used in many different products such as plastic packaging for water and food, storage media, and even in thermal paper. Thermal paper is used for receipts in stores and tickets for parking, bus, and trains. BPA is applied on thermal paper as a dye developer. As a dye developer, it is not chemically bound to the paper so it can easily migrate and be absorbed by the skin (fingers, palm). Studies showed that typical occupational exposures of work cashiers can increase concentrations of BPA and its metabolites in urine several times. Toxicokinetic studies showed that the route of exposure has a big effect on the concentration of BPA that circulates in the body. If BPA enters the body through dermal exposure, it metabolizes as unconjugated BPA, while oral exposure leads to a conjugated form of BPA. Studies showed that only the unconjugated form can bind to estrogen receptors, leading to the conclusion that the unconjugated form is hazardous. Due to that European Commission restricted usage of BPA to 0.02 mas%. The paper manufacturers replaced BPA with bisphenol S (BPS). It is expected that 61 % of all thermal paper in the EU will be BPS-based till now. However, the wide use of BPS in thermal paper raises concern because it was shown that BPS is also toxic. New studies of urine samples collected around the world showed the presance of BPS. Due to increasing production of BPS there is a need for the development of analytical methods for the detection of SVCHs. The most used are HPLCs with mass spectrometric detection, which are expensive and time-consuming. On a another hand, electrochemical sensors are low-cost and simple method for detection of SVCHs. The present study represents fast, reliable and commercial detection of bisphenols via screen-printed electrodes (SPEs) as receptor elements. Scanning electron microscopy (SEM) was used to study the surface of the SPEs working electrodes. SPE electrodes showed very good electrochemical responses toward BPA and BPS oxidation with linear ranges between 0.5 and 50.0 μM and lower limits of detection of 0.15 μM and 0.37 μM, respectively

Development of technical specifications for vehicle management information system

To diplomsko delo naslavlja tehnologije sledenja in vodenja vozil. V ta namen smo najprej preučili trenutno stanja tehnike na področju, čemur je sledil pregled obstoječih rešitev slovenskih podjetij, ki omogočajo tovrstne funkcionalnosti. Ugotovili smo, da obstoječe rešitve nudijo dobro podporo za ogled statusa vozila in njegovo vodenje od točke A do točke B, učinkovite informacijske rešitve za rabo parkirnih prostorov pa danes še ne obstajajo. To je zlasti očitno v kontekstu tovornega prometa, kjer so parkirišča izrazito prezasedena. Iz tega razloga smo zasnovali informacijsko rešitev, ki omogočala tudi tovrstne funkcionalnosti. Izdelali smo tudi tehnične specifikacije in implementirali spletno storitev, ki temelji na koncept geografskega ograjevanja v ogrodju .NET in omogoča spremljanje zasedenosti in vodenje rezervacij parkirišča.This diploma thesis focuses on vehicle tracking and routing technologies. After initial analysis of the contemporary state-of-the-art, we carried out a detailed examination of commercial products offered by Slovenian industry. While most of the solutions allow for efficient monitoring of status of vehicles and their navigation from point A to B, there is a considerable lack of ICT solutions that would allow for efficient management of parking spaces. This aspect is particularly important in the context of generally overcrowded parking space. For this reason, we designed ICT solution that provides the key functionalities for parking space management and define its technical specifications. Implementation of parking-space booking and utilization monitoring was also done a form of .NET geofencing service

Development of an active computer cycling game using a smart trainer

Magistrsko delo naslavlja področje aktivnih računalniških kolesarskih iger. V ta namen smo najprej opisali princip delovanja aktivnih računalniških iger in proučili literaturo o njihovem vplivu na promocijo zdravega načina življenja. Sledil je pregled najpriljubljenejših obstoječih rešitev na trgu. Ugotovili smo, da pri razvijanju omenjenih iger prihaja do razlik predvsem pri načinu generiranju prog, za komunikacijo med napravami se večina obrača na preverjena, brezžična in varčna protokola ANT+ in Bluetooth Low Energy. Na podlagi teh ugotovitev smo v nadaljevanju magistrskega dela razvili aktivno računalniško kolesarsko igro, v kateri igralec vozi po lastnih progah, ki jih predhodno posname z videokamero, za komunikacijo s kolesarskim trenažerjem pa igra uporablja protokol ANT+.The master\u27s thesis addresses the field of active computer cycling games. To this end, we described the principle of operation of such games and examined the literature regarding their impact on promoting a healthy lifestyle. This part was followed by an overview of the most popular solutions already present on the market. We found that the developers of these games take a different approach considering how they generate cycling routes. However, when developing communication between devices, the majority resort to proven, wireless, and energy-efficient protocols ANT + and Bluetooth Low Energy. Considering these findings, we have developed an active computer cycling game where the player rides on his own routes that were previously recorded with a video camera while the ANT+ protocol is being used for communication between the game and the smart trainer

In-Situ Spectroelectrochemical Study of Conductive Polyaniline Forms for Sensor Applications

Our contribution focuses on a correlative study of polyaniline (PANI) electropolymerisation and UV/VIS spectroscopy. PANI was prepared via electro-oxidation using a potentiodynamic method on commercial gold screen-printed electrodes (Au-SPE). By using an in-situ spectroelectrochemical method, the development of the polymer was observed from monomer, monomer oxidation to final polymer formation and its transformations between the oxidation forms. The results confirm the spontaneous doping of the polymer during the polymerisation, the instability of leucoemeraldine form in air and its two-stage oxidation to emeraldine form. The final conductive PANI deposited on Au-SPE will be used as sensor element for the detection of toxic organic compounds

Microstructural insights into the coercivity enhancement of grain-boundary-diffusion-processed Tb-treated Nd-Fe-B sintered magnets beyond the core-shell formation mechanism

We propose a dominant core-shell formation mechanism for grain-boundary-diffusion-processed (GBDP), Tb-treated, Nd2Fe14B sintered magnets. A depth-sensitive analysis of Tb-treated samples, relative to a non-GBDP Nd2Fe14B magnet, showed a 30% increase of the coercivity in the central part of the magnet. A structure-chemistry-magnetic-property analysis revealed the dominant GBDP mechanism. On the surface of the Tb-treated magnet, the Tb is released from the starting precursor following a cascade of chemical reactions between the Tb oxide and the Nd and/or the Nd-Fe-B. The released Tb diffuses along the grain boundaries, forming a core-shell structure. The calculated optimum concentration for a 30% increase in the coercivity was 50 ppm of Tb. Off-axis electron-holography measurements were used to quantitatively map the characteristic magnetic states of the samples, confirming a different magnetic domain structure in the shell than in the core. The magnetic induction in the core was found to be 26% higher than that of the shell, which has a lower magnetic saturation due to the presence of Tb. The results show that the measured increase in the coercivity is due to a structural effect, and not the magnetic contribution of the Tb. Our results pave the way towards grain-boundary-engineering studies that can be used to increase the coercivity of Nd-Fe-B magnets for e-mobility and eco-power applications