Utilisation of microbiosensors for monitoring phenols in whisky fermentation process

Biosensors for the specific, sensitive and rapid detection of analytes could play an important role in fermentation industries such as the whisky industry. Long-standing challenges remain unmet and these are associated with the establishment of low-cost, easy-to-use, miniaturised, robust, reliable and highly specific biosensors. In this paper, an optical method, and more specifically fluorescence, is used for the development of a portable biosensor in combination with enzyme technology and microfabrication for the determination of phenols in smoked whisky. At present, chromatographic techniques are utilised by taking a single sample from the fermentation vessel, which may not be totally representative, so an in situ biosensor can improve the quality control during the fermentation process. The enzyme tyrosinase and a fluorescence ruthenium complex oxygen indicator were used for the detection of different phenol percentage. The enzyme and the indicator were immobilised in polymeric films during the microfabrication process. Furthermore, a comparative assessment of the enzyme and the aptamer technologies are discussed. During the last 20 years since the SELEX method developed, over 2000 papers related to aptamers or SELEX have been published and the aptamer biosensors have been enchanced and many new DNA aptamers have been developed. The utilisation of aptamer technology is discussed and advantages over the enzyme biosensor are highlighted for future work

Cités de Grèce septentrionale portant le nom de Dion

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Workflow for the identification of biotransformation products of amine-containing psychotropic drugs in the aquatic environment

Pharmaceuticals are continuously discarded Pharmaceuticals are continuously discarded into the aquatic system through wastewater treatment plants (WWTPs). The microbial degradation of these organic micropollutants and formation of transformation products (TPs) under aerobic conditions is the fundamental process for their elimination. It is of paramount importance to understand the microbial metabolic pathways so as to obtain knowledge of how fast micropollutants degraded and to assess the exposure to their potential TPs as they can be more polar and consequently environmentally persistent. In this study, batch reactors seeded with activated sludge from the WWTP of Athens were set up to assess biotic, abiotic and sorption losses of selective psychotropic drugs, containing amine moieties. Biodegradation and transformation products were identified using liquid chromatography quadrupole-time-offlight mass spectrometry (LC-QToF-MS). A workflow for target, suspect and non-target screening was developed. Data treatment was performed by using metabolite tools accompanying Bruker’s maxis impact ESI-QToF-MS and the structure elucidation of the candidate transformation products was based on accurate mass and isotopic pattern measurements by HRMS and tentative interpretation of MS/MS spectra. Finally four biotransformation products were identified for both lidocaine and ephedrine. Despite the structure similarities, different degradation constants were calculated for each compound

Targeted determination of more than 1500 micropollutants & transformation products in wastewater samples by liquid chromatography quadrupole-time-of-flight mass spectrometry with an accurate-mass database

High resolution mass spectrometry has dramatically improved the possibilities of the environmental analysis. The present study describes the development of an analytical method, based on liquid chromatography quadrupole-time-of-flight mass spectrometry (LC–QToF-MS) for the target determination of more than 1500 contaminants of emerging concern (CECs) and transformation products (TPs) including, among others, pharmaceuticals, illicit drugs, personal care products, pesticides, industrial chemicals, and sweeteners in wastewater. Analytes were extracted from wastewater samples by mixed mode solid-phase extraction, and data were acquired through broad-band Collision Induced Dissociation (bbCID) mode, providing MS and MS/MS spectra, simultaneously, in both positive and negative ionization mode (two separate runs). The in-house mass spectral database was built by injection of standard solution of the analytes and it includes information of the retention time, parent ions and adducts, as well as fragment ions. The raw data were analyzed with Bruker Target Analysis 1.3 software. Retention time, accurate mass of the precursor ion and adducts, isotopic pattern, in combination with absence of the peak in the procedural blank were the parameters used for confirmation of the target compounds. Experimental fragment ions were also considered, along with the ion ratio, intensity and isotopic pattern. Furthermore, semi-quantitation of these contaminants was possible. The method herein presented, in addition of providing accurate information about the presence of a large number of relevant substances, has the advantage that the data generated can be further processed for suspect and non-target screening, expanding the information on the samples. An important advantage of this method is that retrospective investigation of the data is available to look for the presence of additional CECs and their TPs, which were not considered at the time of the analysi

Biotransformation of citalopram: Insights from identification of transformation products by LC-QToF-MS

Biodegradation is considered to be the key process for the elimination of the majority of pharmaceuticals in the environment. During wastewater treatment or once they are disposed in the aquatic environment, pharmaceuticals may transformed to new, structurally-related compounds which are called transformation products (TPs). Since most of these compounds are unknowns, their identification is essential not only to provide a comprehensive risk assessment on micropollutants in the environment, but also to design improved removal technologies for (pseudo)persistent trace contaminants. In this study, batch reactors seeded with activated sludge from the WWTP of Athens were set up to assess biotic, abiotic and sorption losses of a SSRI drug, citalopram. TPs were identified by reversed-phase liquid chromatography quadrupole-time-of-flight mass spectrometry (RPLC-QToF-MS). Hydrophilic interaction liquid chromatography (HILIC) was also used as a complementary, orthogonal, technique for the identified TPs, instead of NMR. A workflow for suspect and non-target screening was developed. A suspect list of possible TPs was compiled by literature and in silico prediction tools (EAWAG-BBD Pathway Prediction System and Bruker’s Metabolite Predict). Structure elucidation of TPs was based on accurate mass and isotopic pattern measurements and interpretation of MS/MS spectra by the observed fragmentation pattern and library-spectrum match. In total, thirteen TPs were identified. Four out of them were fully identified and confirmed by reference standards (desmethylcitalopram, citalopram amide, citalopram carboxylic acid and 3-oxo-citalopram). A probable structure based on diagnostic evidence and tentative candidates were proposed for the additional five and four TPs, respectively. Finally, a transformation pathway based on the identified compounds was presented

Smart SU-8 Pillars Implemented in a Microfluidic Bioreactor for Continuous Measurement of Glucose

In this contribution we explore a new and simple approach for immobilizing enzymes like glucose oxidase on SU-8 surfaces to develop a smart substrate integrated in microfluidics. SU-8 is a well known photoresist often used in microfluidic prototyping. Immobilization of enzymes on such substance can open new possibilities in the microfabrication of enzyme biosensors and bioreactors. To demonstrate the consistency of this approach, we describe the design, fabrication and the simple functionalization of a microfluidic bioreactor employing smart SU-8 pillars for continuous amperometric measurement of glucose. The results reveal the possibility of simply binding enzymes on SU-8 surface. Moreover, a significant improvement in the linear response range is observed compared to the previous published amperometric microfluidic glucose sensors

Identification of biotransformation products of citalopram formed in activated sludge

Citalopram (CTR) is a highly consumed antidepressant which is removed incompletely by conventional wastewater treatment. Although it is highly detected in effluent wastewaters, little is known about its behavior and transformation processes that undergo during wastewater treatment. The present study aims to expand the knowledge on fate and transformation of CTR during the biological breakdown process. For this purpose, biotransformation batch reactors were set up to assess biotic, abiotic and sorption losses of this compound. One of the main objectives of the study was the identification of the formed transformation products (TPs) by applying suspect and non-target strategies based on liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). In this regard, the complementary use of reversed phase chromatography (RP) and hydrophilic interaction liquid chromatography (HILIC) in the identification of polar TPs, the deep evaluation of the obtained MS/MS spectra, as well as the use of in-house developed quantitative structure-retention relationship (QSRR) retention time prediction models provided valuable support to identification. Fourteen TPs were detected. Thirteen of them were tentatively identified. Four compounds were confirmed (N-desmethylCTR, CTR amide, CTR carboxylic acid and 3-oxo-CTR) through the purchase of the corresponding reference standard. Probable structures based on diagnostic evidence were proposed for the additional nine TPs. A transformation pathway for the biotransformation of CTR was proposed. The presence of the identified TPs was assessed in real wastewater samples through retrospective analysis resulting in the detection of five compounds. Finally, the potential ecotoxicological risk posed by CTR and its TPs to different trophic levels of aquatic organisms, exposed to the studied effluents, was evaluated by means of risk quotients

Concentrations of VOCs and ozone in indoor environments: A case study in two Mediterranean cities during winter period

Building materials represent the largest surfaces indoors and are the major contributors of volatile organic compounds (VOCs) in the indoor environment. This study which is conducted in the frame of BUMA project (Prioritization of Building Materials Emissions), aims at assessing the human exposure to air hazards emitted by building materials. In this study, indoor and outdoor VOCs and ozone measurements from field campaigns in two Mediterranean cities (Nicosia and Athens in winter period) are presented and discussed. The field campaigns concern weekly measurements. The campaigns were conducted in four buildings in each city (1 Public building, 1 school and 2 houses) and concern weekly measurements. Passive samplers were used for collecting VOCs and ozone. Eight (8) hydrocarbons (benzene, toluene, ethylbenzene, m,p-xylene, a-pinene, o-xylene and d-limonene), five (5) carbonyl compounds (formaldehyde, acetaldehyde, proprionaldehyde, acetone and hexanaldehyde) and ozone have been measured. Additional air exchange measurements have been conducted using tracer gas techniques. Hazardous substances such as benzene, formaldehyde and acetaldehyde present indoor concentrations that range between 1.5-10.2, 5.8-43.2 and 4.5-15 μg/m3, respectively. VOC concentration data show a considerable variability due to the different indoor emission sources, ventilation rates and outdoor environment's influence. A significant contribution to indoor measured concentrations seems to come from the building materials. Ozone outdoor concentrations are reduced substantially inside, indicating relatively strong indoor ozone sinks