A university campus case study

Funding Information: The authors would like to thank Fundação para a Ciência e Tecnologia (FCT - Portugal), Volkswagen Autoeuropa and NMT, S. A. for co-financing of PhD grant PD/BDE/150627/2020, from Doctoral NOVA I4H Program. Funding Information: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Fundação para a Ciência e Tecnologia FCT – Portugal and Volkswagen Autoeuropa - Portugal, which co-financed the PhD grant PD/BDE/150627/2020 from Doctoral NOVA I4H Program; and NMT, S. A. – Portugal for the supply of the GC-IMS device and additional resources. Publisher Copyright: © The Author(s) 2022.Society’s concerns about the citizens’ exposure to possibly dangerous environments have recently risen; nevertheless, the assessment of indoor air quality still represents a major contemporary challenge. The volatile organic compounds (VOCs) are among the main factors responsible for deteriorating air quality conditions. These analytes are very common in daily-use environments and they can be extremely hazardous to human health, even at trace concentrations levels. For these reasons, their quick detection, identification, and quantification are crucial tasks, especially for indoor and heavily-populated scenarios, where the exposure time is usually quite long. In this work, a Gas Chromatography – Ion Mobility Spectrometry (GC-IMS) device was used for continuous monitoring indoor and ambient air environments at a large-scale, due to its outstanding levels of sensibility, selectivity, analytical flexibility, and almost real-time monitoring capability. A total of 496 spectra were collected from 15 locations of a university campus and posteriorly analysed. Overall, 23 compounds were identified among the 31 detected. Some of them, like Ethanol and 2-Propanol, were reported as being very hazardous to the human organism, especially in indoor environments. The achieved results confirmed the suitability of GC-IMS technology for air quality assessment and monitoring of VOCs and, more importantly, proved how dangerous indoor environments can be in scenarios of continuous exposure.publishersversionpublishe

A gas chromatography–ion mobility spectrometry applicability study

The authors acknowledge NMT. S. A. for supplying the GC-IMS device and additional resources. Publisher Copyright: © The Author(s) 2023.Contemporary life is mostly spent in indoor spaces like private houses, workplaces, vehicles and public facilities. Nonetheless, the air quality in these closed environments is often poor which leads to people being exposed to a vast range of toxic and hazardous compounds. Volatile organic compounds (VOCs) are among the main factors responsible for the lack of air quality in closed spaces and, in addition, some of them are particularly hazardous to the human organism. Considering this fact, we conducted daily in situ air analyses over 1 year using a gas chromatography–ion mobility spectrometry (GC-IMS) device in an indoor location. The obtained results show that 10 VOCs were consistently present in the indoor air throughout the entire year, making them particularly important for controlling air quality. All of these compounds were successfully identified, namely acetic acid, acetone, benzene, butanol, ethanol, isobutanol, propanoic acid, propanol, 2-propanol and tert-butyl methyl ether. The behaviour of the total VOCs (tVOCs) intensity during the period of analysis and the relative variation between consecutive months were studied. It was observed that the overall trend of tVOCs closely mirrored the variation of air temperature throughout the year suggesting their strong correlation. The results obtained from this study demonstrate the high quality and relevance of the data, highlighting the suitability of GC-IMS for in situ long-term air quality assessment in indoor environments and, consequently, for identifying potential health risks for the human organism in both short-term and long-term exposure scenarios.publishersversionpublishe

A review

Funding Information: PhD grant PD/BDE/150627/2020 was financed by Fundação para a Ciência e Tecnologia (FCT - Portugal) and Volkswagen Autoeuropa. Funding Information: The authors would like to thank Fundação para a Ciência e Tecnologia (FCT - Portugal), and Volkswagen Autoeuropa for co-financing the doctoral grant PD/BDE/150627/2020. Publisher Copyright: © 2023 The AuthorsIon Mobility Spectrometry (IMS) has gained relevance in the field of analytical techniques over the past decades. If compared with well-established techniques like mass spectrometry or infrared spectroscopy, IMS is considerably less developed or employed in specific fields but presents promising results and a substantial margin for improvements. Its outstanding sensitivity and selectivity, analytical flexibility, instrumental versatility and almost real-time results capacity have contributed to elevate IMS among the main analytical techniques for the detection of volatile organic compounds. Due to its growth potential, it is mandatory to assess in which scientific fields IMS has played a relevant role in the past years of academic research and understand in which areas it can become equally important in the near future. For this purpose, hundreds of scientific works from the past ten years were addressed and the most relevant were reviewed in this work. Three main categories of IMS applications were defined to group the reviewed articles: Environmental and Safety Research, Health Research and Food Research. In addition, some original studies were specifically developed for this review paper, to act as elucidative examples. The working principle of the IMS is included for clarification purposes. A glossary of all the mentioned compounds was also included. Throughout the text, it is clear how relevant IMS has become and how diverse its applicability can be, ranging from simpler topics like fraud detection to more complex ones like pathologies diagnosis. It is safe to say that IMS has been, step by step, gaining relevance as an analytical technique and its potential for supporting many diverse scientific fields is evident.publishersversionpublishe

Estudo do controlo corticomotor com recurso a eletromiografia multicanal

Atualmente, o sistema nervoso ainda é fonte de muito desconhecimento, no entanto, tem sido realizada muita investigação no sentido de deslindar todas as suas particularidades. A forma como a comunicação entre o sistema nervoso e os músculos ocorre, em particular, também não é totalmente conhecida. Diversos trabalhos têm vindo a comprovar que esta está intimamente ligada a fenómenos de sincronia entre a atividade elétrica neuronal e muscular, nomeadamente, durante o controlo corticomotor. Nesta dissertação pretende-se contribuir positivamente para esta investigação. Para isso, pretende-se recolher sinais de EEG e de EMG durante a realização de uma tarefa motora, a fim de se perceber que áreas do antebraço são mais relevantes para o estudo dos fenómenos de sincronia. Pretende-se ainda perceber se existe alguma relação ou dependência entre o o ajuste em frequência e o ajuste em fase dos sinais. Na dissertação, construiu-se uma manga eletromiográfica e recorreu-se a um cap eletroencefalográfico para se fazer a recolha dos sinais enquanto os voluntários cumpriam uma atividade motora pedida que consistiu em jogar um jogo obrigando, desta forma, a que exista um controlo motor contínuo durante as recolhas. Em seguida os dados foram analisados com algoritmos de separação por descorrelação temporal (TDSEP) e estudou-se a coerência das fontes em relação a um sinal referência, e de análise com referência de fase (RPA) para se estudar o ajuste em fase. Conclui-se que o ajuste em fase entre sinais efetivamente ocorre durante o controlo corticomotor, no entanto, em nada está relacionado ou dependente do ajuste em frequência dos mesmos. Provou-se, ainda, que as melhores zonas do braço para se verificar o ajuste em fase são a zona proximal do antebraço, distal posterior do antebraço e a zona entre os dedos indicador e polegar da mão. Estas conclusões têm inúmeras aplicações práticas, nomeadamente, ao nível clínico, como por exemplo, em casos de Acidente Vascular Cerebral ou em doentes de Parkinson

Differentiation of the Organoleptic Volatile Organic Compound Profile of Three Edible Seaweeds

Funding Information: This research was funded by FUNDAÇÃO PARA A CIÊNCIA E TECNOLOGIA (FCT—PORTUGAL), grant number PD/BDE/150627/2020. This research was funded by MAR2020 – PORTUGUESE GOVERNMENT, project number MAR-01.03.0-FEAMP-0016. Funding Information: P.C.M. acknowledges Fundação para a Ciência e Tecnologia (FCT—Portugal) for his doctoral grant (PD/BDE/150627/2020). Publisher Copyright: © 2023 by the authors.The inclusion of seaweeds in daily-consumption food is a worthy-of-attention challenge due to their high nutritional value and potential health benefits. In this way, their composition, organoleptic profile, and toxicity must be assessed. This work focuses on studying the volatile organic compounds (VOCs) emitted by three edible seaweeds, Grateloupia turuturu, Codium tomentosum, and Bifurcaria bifurcata, with the aim of deepening the knowledge regarding their organoleptic profiles. Nine samples of each seaweed were prepared in glass vials, and the emitted headspace was analyzed, for the first time, with a gas chromatography—ion mobility spectrometry device, a highly sensitive technology. By statistically processing the collected data through PCA, it was possible to accurately differentiate the characteristic patterns of the three seaweeds with a total explained variance of 98%. If the data were pre-processed through PLS Regression, the total explained variance increased to 99.36%. The identification of 13 VOCs was accomplished through a developed database of compounds. These outstanding values in addition to the identification of the main emissions of VOCs and the utilization of a never-before-used technology prove the capacity of GC-IMS to differentiate edible seaweeds based solely on their volatile emissions, increase the knowledge regarding their organoleptic profiles, and provide an important step forward in the inclusion of these highly nutritional ingredients in the human diet.publishersversionpublishe

Diagnosis of Carcinogenic Pathologies through Breath Biomarkers: Present and Future Trends

The assessment of volatile breath biomarkers has been targeted with a lot of interest by the scientific and medical communities during the past decades due to their suitability for an accurate, painless, non-invasive, and rapid diagnosis of health states and pathological conditions. This paper reviews the most relevant bibliographic sources aiming to gather the most pertinent volatile organic compounds (VOCs) already identified as putative cancer biomarkers. Here, a total of 265 VOCs and the respective bibliographic sources are addressed regarding their scientifically proven suitability to diagnose a total of six carcinogenic diseases, namely lung, breast, gastric, colorectal, prostate, and squamous cell (oesophageal and laryngeal) cancers. In addition, future trends in the identification of five other forms of cancer, such as bladder, liver, ovarian, pancreatic, and thyroid cancer, through perspective volatile breath biomarkers are equally presented and discussed. All the results already achieved in the detection, identification, and quantification of endogenous metabolites produced by all kinds of normal and abnormal processes in the human body denote a promising and auspicious future for this alternative diagnostic tool, whose future passes by the development and employment of newer and more accurate collection and analysis techniques, and the certification for utilisation in real clinical scenarios

Breath volatile organic compounds (VOCs) as biomarkers for the diagnosis of pathological conditions: A review

Normal and abnormal/pathological status of physiological processes in the human organism can be characterized through Volatile Organic Compounds (VOCs) emitted in breath. Recently, a wide range of volatile analytes has risen as biomarkers. These compounds have been addressed in the scientific and medical communities as an extremely valuable metabolic window. Once collected and analysed, VOCs can represent a tool for a rapid, accurate, non-invasive, and painless diagnosis of several diseases and health conditions. These biomarkers are released by exhaled breath, urine, faeces, skin, and several other ways, at trace concentration levels, usually in the ppbv (μg/L) range. For this reason, the analytical techniques applied for detecting and clinically exploiting the VOCs are extremely important. The present work reviews the most promising results in the field of breath biomarkers and the most common methods of detection of VOCs. A total of 16 pathologies and the respective database of compounds are addressed. An updated version of the VOCs biomarkers database can be consulted at: https://neomeditec.com/VOCdatabase

In Situ Indoor Air Volatile Organic Compounds Assessment in a Car Factory Painting Line

Proper working conditions must be one of the employers’ main concerns in any type of company but particularly in work locations where the employees are chronically exposed to hazardous compounds, like factories and production lines. Regarding this challenge, the present research addresses the mapping of a car factory painting line to possibly toxic volatile organic compounds emitted by all the coatings and chemicals used during the work shifts for the future evaluation of employees’ exposure. For the first time, a Gas Chromatography–Ion Mobility Spectrometry device was employed for the in situ detection of volatile organic compounds in an automotive factory. A total of 26 analytes were detected at nine different locations, of which 15 VOCs were accurately identified. Pure chemical-grade substances were used for the development of the VOC database. Although quantitative analysis was not the goal of this study, a calibration model was presented to one analyte for exemplificative purposes. Relative intensity profiles were plotted for all locations, revealing that some indoor VOCs can reach intensity levels up to 60 times higher than in outdoor air samples. The achieved results proved that the painting line has an abundant number of VOCs emitted from different sources and may lead to serious health risks for the employees. Additional studies shall be developed in the painting line for quantitative evaluation of the existing VOCs and their influence on the employees’ health conditions

Suitability of Short- and Long-Term Storage of Volatile Organic Compounds Samples in Syringe-Based Containers: A Comparison Study

The employment of advanced analytical techniques and instrumentation enables the tracing of volatile organic compounds (VOCs) in vestigial concentrations (ppbv-pptv range) for several emerging applications, such as the research of disease biomarkers in exhaled air, the detection of metabolites in several biological processes, and the detection of pollutants for air quality control. In this scope, the storage of gaseous samples is crucial for preserving the integrity and stability of the collected set of analytes. This study aims to assess the suitability of three commercially available syringes as air containers (AC) that are commonly used for the collection, storage, isolation, and transportation of samples: glass syringes with glass plungers (AC1), and two plastic syringes, one with plastic plungers (AC2), and one with rubbered plungers (AC3). For this purpose, 99 air samples with different times of storage (from 10 min to 24 h) were analyzed using a Gas Chromatography—Ion Mobility Spectrometry device and the degradation of the samples was properly assessed by comparing the changes in the VOCs’ emission profiles. The quality of the method was assured by via the measurement of the blank’s spectra before each experimental run, as well as by the consecutive measurement of the three replicates for each sample. A statistical analysis of the changes in the VOCs’ emission patterns was performed using principal component analysis (PCA). The results, with a total explained variance of 93.61%, indicate that AC3 is the most suitable option for the long-term storage of air samples. Thus, AC3 containers demonstrated a higher capacity to preserve the stability and integrity of the analytes compared to AC1 and AC2. The findings of the short-term effects analysis, up to 1 h, confirm the suitability of all analyzed syringe-based containers for sample-transferring purposes in onsite analysis

The State of the Art on Graphene-Based Sensors for Human Health Monitoring through Breath Biomarkers

The field of organic-borne biomarkers has been gaining relevance due to its suitability for diagnosing pathologies and health conditions in a rapid, accurate, non-invasive, painless and low-cost way. Due to the lack of analytical techniques with features capable of analysing such a complex matrix as the human breath, the academic community has focused on developing electronic noses based on arrays of gas sensors. These sensors are assembled considering the excitability, sensitivity and sensing capacities of a specific nanocomposite, graphene. In this way, graphene-based sensors can be employed for a vast range of applications that vary from environmental to medical applications. This review work aims to gather the most relevant published papers under the scope of “Graphene sensors” and “Biomarkers” in order to assess the state of the art in the field of graphene sensors for the purposes of biomarker identification. During the bibliographic search, a total of six pathologies were identified as the focus of the work. They were lung cancer, gastric cancer, chronic kidney diseases, respiratory diseases that involve inflammatory processes of the airways, like asthma and chronic obstructive pulmonary disease, sleep apnoea and diabetes. The achieved results, current development of the sensing sensors, and main limitations or challenges of the field of graphene sensors are discussed throughout the paper, as well as the features of the experiments addressed