Quality Monitoring
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2022 ◽  
Vol 9 ◽  
Jinhua Shao ◽  
Chao Wang ◽  
Yiling Shen ◽  
Jinlei Shi ◽  
Dongqing Ding

Tea is a popular beverage all around the world. Tea composition, quality monitoring, and tea identification have all been the subject of extensive research due to concerns about the nutritional value and safety of tea intake. In the last 2 decades, research into tea employing electrochemical biosensing technologies has received a lot of interest. Despite the fact that electrochemical biosensing is not yet the most widely utilized approach for tea analysis, it has emerged as a promising technology due to its high sensitivity, speed, and low cost. Through bibliometric analysis, we give a systematic survey of the literature on electrochemical analysis of tea from 1994 to 2021 in this study. Electrochemical analysis in the study of tea can be split into three distinct stages, according to the bibliometric analysis. After chromatographic separation of materials, electrochemical techniques were initially used only as a detection tool. Many key components of tea, including as tea polyphenols, gallic acid, caffeic acid, and others, have electrochemical activity, and their electrochemical behavior is being investigated. High-performance electrochemical sensors have steadily become a hot research issue as materials science, particularly nanomaterials, and has progressed. This review not only highlights these processes, but also analyzes and contrasts the relevant literature. This evaluation also provides future views in this area based on the bibliometric findings.

Biosensors ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 42
B M Azizur Rahman ◽  
Charusluk Viphavakit ◽  
Ratchapak Chitaree ◽  
Souvik Ghosh ◽  
Akhilesh Kumar Pathak ◽  

The increasing use of nanomaterials and scalable, high-yield nanofabrication process are revolutionizing the development of novel biosensors. Over the past decades, researches on nanotechnology-mediated biosensing have been on the forefront due to their potential application in healthcare, pharmaceutical, cell diagnosis, drug delivery, and water and air quality monitoring. The advancement of nanoscale science relies on a better understanding of theory, manufacturing and fabrication practices, and the application specific methods. The topology and tunable properties of nanoparticles, a part of nanoscale science, can be changed by different manufacturing processes, which separate them from their bulk counterparts. In the recent past, different nanostructures, such as nanosphere, nanorods, nanofiber, core–shell nanoparticles, nanotubes, and thin films, have been exploited to enhance the detectability of labelled or label-free biological molecules with a high accuracy. Furthermore, these engineered-materials-associated transducing devices, e.g., optical waveguides and metasurface-based scattering media, widened the horizon of biosensors over a broad wavelength range from deep-ultraviolet to far-infrared. This review provides a comprehensive overview of the major scientific achievements in nano-biosensors based on optical fiber, nanomaterials and terahertz-domain metasurface-based refractometric, labelled and label-free nano-biosensors.

2022 ◽  
Tatiana Macé ◽  
Maitane Iturrate-Garcia ◽  
Céline Pascale ◽  
Bernhard Niederhauser ◽  
Sophie Vaslin-Reimann ◽  

Abstract. The measurement of ammonia (NH3) in ambient air is a sensitive and priority topic due to its harmful effects on human health and ecosystems. NH3 emissions have continuously increased over the last century in Europe, because of intensive livestock practices and enhanced use of nitrogen-based fertilizers. European air quality monitoring networks monitor atmospheric NH3 amount fractions. However, the lack of stable reference gas mixtures (RGMs) at atmospheric amount fractions to calibrate NH3 analyzers is a common issue of the networks, which results in data that are not accurate, traceable and, thus, geographically comparable. In order to cover this lack, LNE developed, in close collaboration with the company 2M PROCESS, a gas reference generator to generate dynamically NH3 RGMs in air. The method is based on gas permeation and further dynamic dilution to obtain an amount fraction range between 1 and 400 nmol/mol. The calibration of the elements of the generator against LNE primary standards ensures the traceability of the RGMs to the international system of units. Furthermore, the highly accurate flow and oven temperature measurements of the reference generator, together with the associated calibration procedure defined by LNE, guarantee relative expanded uncertainties of the calibration of the NH3 analyzer calibrations lower than 2 % (coverage factor = 2). This result is very satisfactory considering the low NH3 amount fraction levels (1 to 400 nmol/mol) and the phenomena of adsorption and desorption, especially in the presence of traces of water on the surfaces in contact. A bilateral comparison was organized between METAS and LNE, consisting on the calibration of a PICARRO G2103 gas analyzer by both national metrology institutes (NMI). The results highlighted the good agreement between the NH3 reference generators developed by the two institutes and allowed to validate both LNE’s reference generator and calibration procedure. The development of the NH3 reference generator has already raised great interest within the French air quality monitoring networks (AASQA). Since the end of 2020, LNE calibrated several NH3 analyzers of the networks. These requests shows the interest of the AASQA in the development of this new gas reference generator to guarantee the traceability of measurements carried out on the French territory.

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 120
Haoran Zhai ◽  
Jiaqi Yao ◽  
Guanghui Wang ◽  
Xinming Tang

Based on measurement data from air quality monitoring stations, the spatio-temporal characteristics of the concentrations of particles with aerodynamic equivalent diameters smaller than 2.5 and 10 μm (PM2.5 and PM10, respectively) in the Beijing–Tianjin–Hebei (BTH) region from 2015 to 2018 were analysed at yearly, seasonal, monthly, daily and hourly scales. The results indicated that (1) from 2015 to 2018, the annual average values of PM2.5 and PM10 concentrations and the PM2.5/PM10 ratio in the study area decreased each year; (2) the particulate matter (PM) concentration in winter was significantly higher than that in summer, and the PM2.5/PM10 ratio was highest in winter and lowest in spring; (3) the PM2.5 and PM10 concentrations exhibited a pattern of double peaks and valleys throughout the day, reaching peak values at night and in the morning and valleys in the morning and afternoon; and (4) with the use of an improved sine function to simulate the change trend of the monthly mean PM concentration, the fitting R2 values for PM2.5 and PM10 in the whole study area were 0.74 and 0.58, respectively. Moreover, the high-value duration was shorter, the low-value duration was longer, and the concentration decrease rate was slower than the increase rate.

2022 ◽  
Vol 7 ◽  
R. S. McLeod ◽  
M. Mathew ◽  
D. Salman ◽  
C. L. P. Thomas

Young people spend extended periods of time in educational buildings, yet relatively little is known about the air quality in such spaces, or the long-term risks which contaminant exposure places on their health and development. Although standards exist in many countries in relation to indoor air quality in educational buildings, they are rarely subject to detailed post-occupancy evaluation. In this study a novel indoor air quality testing methodology is proposed and demonstrated in the context of assessing the post-occupancy performance of a recently refurbished architecture studio building at Loughborough University, United Kingdom. The approach used provides a monitoring process that was designed to evaluate air quality in accordance with United Kingdom national guidelines (Building Bulletin 101) and international (WELL Building) standards. Additional, scenario-based, testing was incorporated to isolate the presence and source of harmful volatile organic compounds, which were measured using diffusive sampling methods involving analysis by thermal desorption - gas chromatography - mass spectrometry techniques. The findings show that whilst the case-study building appears to perform well in respect to existing national and international standards, these guidelines only assess average CO2 concentrations and total volatile organic compound limits. The results indicate that existing standards, designed to protect the health and wellbeing of students, are likely to be masking potentially serious indoor air quality problems. The presence of numerous harmful VOCs found in this study indicates that an urgent revaluation of educational building procurement and air quality monitoring guidelines is needed.

2022 ◽  
Vol 5 ◽  
Rhys Manners ◽  
Julius Adewopo ◽  
Marguerite Niyibituronsa ◽  
Roseline Remans ◽  
Aniruddha Ghosh ◽  

Diet quality is a critical determinant of human health and increasingly serves as a key indicator for food system sustainability. However, data on diets are limited, scattered, often project-dependent, and current data collection systems do not support high-frequency or consistent data flows. We piloted in Rwanda a data collection system, powered by the principles of citizen science, to acquire high frequency data on diets. The system was deployed through an unstructured supplementary service data platform, where respondents were invited to answer questions regarding their dietary intake. By combining micro-incentives with a normative nudge, 9,726 responses have been crowdsourced over 8 weeks of data collection. The cost per respondent was < $1 (system set-up, maintenance, and a small payment to respondents), with interactions taking <15 min. Exploratory analyses show that >70% of respondents consume tubers and starchy vegetables, leafy vegetables, fruits, legumes, and wholegrains. Women consumed better quality diets than male respondents, revealing a sex-based disparity in diet quality. Similarly, younger respondents (age ≤ 24 years) consumed the lowest quality diets, which may pose significant risks to their health and mental well-being. Middle-income Rwandans were identified to have consumed the highest quality diets. Long-term tracking of diet quality metrics could help flag populations and locations with high probabilities of nutrition insecurity, in turn guiding relevant interventions to mitigate associated health and social risks.

Chemosensors ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 22
Sue-Yuan Fan ◽  
Sucharita Khuntia ◽  
Christine Heera Ahn ◽  
Bing Zhang ◽  
Li-Chia Tai

Recent advances in electrochemical devices have sparked exciting opportunities in the healthcare, environment, and food industries. These devices can be fabricated at low costs and are capable of multiplex monitoring. This overcomes challenges presnted in traditional sensors for biomolecules and provides us a unique gateway toward comprehensive analyses. The advantages of electrochemical sensors are derived from their direct integration with electronics and their high selectivity along with sensitivity to sense a wide range of ionic analytes at an economical cost. This review paper aims to summarize recent innovations of a wide variety of electrochemical sensors for ionic analytes for health care and industrial applications. Many of these ionic analytes are important biomarkers to target for new diagnostic tools for medicine, food quality monitoring, and pollution detection. In this paper, we will examine various fabrication techniques, sensing mechanisms, and will also discuss various future opportunities in this research direction.

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