Paper-based analytical devices for environmental analysis.

The increasing demand for fast and on-site information has generated great interest in developing simple and portable analytical devices that provide reliable responses. Electroanalytical devices fit perfectly with these purposes because of their ease of use, low cost and facility of miniaturization. Moreover, the growing interest in the construction of do-it-yourself electronic devices has spread the use of common and mass-produced materials for the development of analytical devices. In this context, it is presented here the use of gold-plated pins, from standard connections, and stainless-steel pins, from needlework, as electrodes in (bio)electroanalytical platforms. Three different analytical platforms combining those pins with paper, transparency sheets or micropipette tips were constructed and applied in food and environmental analyses: glucose determination in beverages and surfactant analysis in water.

Using the Rubik's Cube to directly produce paper analytical devices for quantitative point-of-care aptamer-based assays

This paper describes the development of a low-cost paper-based colorimetric analytical device for the accurate and rapid determination of sulfide. Under optimized conditions, Na2S was dropped in the uptake zone I and the probe in the uptake zone II, they converged to the detection zone via capillary force and formed an intense pink resorufin. Sulfide can be quantified based on the average color intensity values of the product “free resorufin”. The color intensity is recorded using a camera phone, and quantification was made using Adobe Photoshop. The as-developed analytical device detected sulfide in the range of 5–400 μM (R2 = 0.982) with the limit of detection (LOD) 1 μM, and was successfully applied in sulfide assay in spiked water samples including tap water and simulated waste water. Colorimetric results from the proposed paper-based colorimetric analytical device were consistent with that from methylene blue (MB) method.

Rubber concrete reinforced with macro fibers recycled from waste GFRP composites: Mechanical properties and environmental impact analysis

In this article a comprehensive overview of the developments in the field of electrochemical stripping analysis with microelectrode arrays and microfabricated devices is presented. Due to the vastness of the topic, this mini-review deals only with the use of regular microelectrode arrays. After the description of the main fabrication methodologies employed, a large part of the review is dedicated to applications, categorised by the electrode material. Microelectrode arrays have found application in several areas of electroanalytical science including clinical and environmental analysis. They have been used for the detection of heavy metals in waters, soil extracts and blood, proving to be reliable analytical devices and bringing the advantages of low-cost, simplicity of use and easy adaptability to field measurement. In many applications, limits of detection are sub-parts per billion. Finally a short section of the review discusses miniaturised potentiostats.

Catecholamines (epinephrine, norepinephrine, and levodopa) are a kind of neurotransmitter with similar structure, which orchestrates the regulation of emotional balance, stress adaptation, cardiovascular system optimization, and energy metabolism coordination. To satisfy the actual requirements for rapid, accurate, and on-site detection of multiple catecholamines, we propose a programmable paper-based microfluidic chip, which is loaded with diethanolamine as a multifunctional and efficient non-fluorescent detection probe. Specifically, diethanolamine reacts with epinephrine, norepinephrine, and levodopa to generate polymer carbon dots with yellow, green, and blue fluorescence. On this basis, the integration of paper-based microfluidics with smartphone-assisted technology enables the intelligent visual fluorescence detection of multiple catecholamines. The analytical device exhibits a good linear relationship in the detection of epinephrine (0.008 ~ 0.5mM), norepinephrine (0 ~ 0.2mM), and levodopa (0.004 ~ 0.06mM), with lower limits of detection of7.4, 19.6, and 1.6μM, respectively. The practicability and efficiency of the analytical detection device were further demonstrated through the analysis of human serum samples. The intelligent analytical device for the individual quantitative detection and visual differentiation of epinephrine, norepinephrine, and levodopa provides a novel and exciting avenue for accurate detection of multiple catecholamines.

This study examines Shein’s ultra-fast fashion model and its global expansion strategy. The research focuses on how Shein competes with traditional well-established brands like Zara and H&M in the fast fashion industry through digital marketing and cost-effective operations. At the same time, Shein also faces risks related to sustainable development, policy regulations, and brand reputation. This article employs the PESTEL and SWOT frameworks to conduct a systematic analysis of the external environment, internal strengths and weaknesses, and deeper social environmental impacts from different perspectives and disciplinary viewpoints. The final research structure indicates that Shein’s rapid growth has significant advantages in terms of efficiency and market penetration. However, its low-cost production and manufacturing model, as well as its lack of originality, have led to insufficient long-term competitiveness. The research has put forward many strategic suggestions targeting Shein's weaknesses, including accelerating the transformation towards sustainability, ensuring transparency in the supply chain, diversifying the brand, and deepening digital applications. Overall, this article provides a useful reference for ultra-fast fashion e-commerce to achieve sustainable growth under the global environmental, social, governance (ESG) expectations.

Paper-based optical nanosensors – A review

Borax, salicylic acid, nitrite, and nitrate have been used as food additives during processing for preserving, coloring, and stabilizing food. These four chemical food additives impact consumer health, e.g., liver cancer and gastric cancer. To maintain the high quality of food and to comply with food safety, a paper-based analytical device (PAD) coupled with a colorimetric method is proposed to simultaneously determine these four chemical food additives in this work. The Griess reaction can be used for the determination of nitrite, and nitrate was reduced to nitrite on the PAD in the section with a hydrophilic channel coated with zinc dust prior to detection by the Griess reaction. Borax and salicylic acid were determined using the complexation reactions with curcumin and FeCl₃, respectively. This work presents the development of colorimetric methods on a PAD for the simultaneous determination of borax, salicylic acid, nitrite and nitrate in food samples. Limits of detection were (mg/L) 10 for borax, 35 for salicylic acid and 0.4 for nitrite and nitrate. Our PAD with a colorimetric method was also used for the determination of borax, salicylic acid, nitrite and nitrate in real food samples. Our detection limits were 3−5 times lower than those of commercial test kits, and the results from the real food samples were not statistically significantly different from those obtained via UV-Vis spectrophotometry at the 95% confidence level (t-test paired samples). Our proposed PAD can rapidly determine four chemical food additives in food with a high sensitivity and is an instrument-free technique.

The rapid growth and development of artificial intelligence (AI) in the way people live, work and interact has brought a number of benefits. But at the same time, it also generates debate from an ethical, social or environmental perspective and in relation to its evolution, expansion and adoption. Artificial intelligence (AI) is a powerful tool that is revolutionising many sectors, including the environment. Through advanced algorithms and machine learning capabilities, AI offers innovative solutions to address environmental challenges, from natural resource management to climate change mitigation. We will explore how AI can improve the environment in some of the most high-profile areas: biodiversity monitoring and conservation, sustainable agriculture, waste management, renewable energy and environmental data analysis. In short, to seek and analyse solutions to overcome the challenges of the future that climate change may bring. Solutions that involve governments, non-governmental organisations, local communities, scientists and the private sector.

A paper-based colorimetric assay with non-instrumental detection for determination of boron in water samples

In recent years, the development of colorimetric methods has gained attention again. This is due to the popularization of electronic devices for digital images acquisition, these devices are shown to be promising substitutes for the spectrophotometer, classic equipment used for colorimetric measurements. The use of digital images to perform colorimetric measurements enables the development of low-cost methods. To enable the miniaturization and development of portable platforms, it is possible to employ paper-based analytical devices as a reaction platform. The development of analytical methods for food quality control is very important to ensure quality parameters and detect possible contaminants. In this sense, the proposed work aims to develop two low-cost analytical methods to assess the presence of contaminants and ensure quality parameters in beverages. The first method aims to determine copper in sugarcane spirits samples using paper-based analytical devices. The use of paper as a reaction platform made it possible to use the Na-DDTC reagent, which in solution would need an extraction step with the appropriate solvent. The proposed method has a limit of quantification of 3 mg L-1, linear range 3 – 25 mg L-1 with R2 >0.99, precision (n = 10) 2.9%. When the method was applied to sugarcane spirit samples, it presented recovery values from 90.1 to 109.5%, showing that it is possible to apply the proposed method in samples of cachaça. The second method aims to determine sulfite in concentrated juice samples using paper based analytical devices, in addition to using the 3D printing technique to enable the construction of a platform to carry out the gas diffusion micro extraction (GDME) step. digital images to evaluate the colorimetric reaction were obtained by applying a smartphone (Galaxy S20+). The method has a quantification limit of 5 mg L-1, linear range 5 – 90 mg L-1 with R2>0.99; precision (n = 5) 2.2%. And when applied to analysis of concentrated juice samples, it showed excellent recovery value of 106.9%. Showing that it is possible to apply the proposed method to perform sulfite measurements in concentrated juice samples.

Automation Highlights from the Literature

The rapid economic growth of China in the last twenty years has caused a commensurate rise in atmospheric pollution which has had an impact on both the environment and public health. Since 2013, SO2, CO2 and nitrogen oxide levels have reached a level that may cause climate change and have adverse effects on the health of the local residents. Past environmental efficiency analyses have rarely examined economic development, air pollution and health as interacting systems; therefore, this study used a new two-stage DEA model, the Modified Undesirable EBM Two Stage DEA (Epsilon-Based Measure) to explore the environmental, economic and health efficiencies in thirty-one major cities in China. The results were as follows: while all cities needed to improve their GDP, the environmental efficiencies were continuing to rise in most cities. The health efficiency index indicated that disease efficiency had increased in most cities but declined in one third; therefore, it is necessary to strengthen treatment. The respiratory disease treatment efficiency in most cities was rising, and the room for improvement had significantly reduced. There were improvements in the mortality rate in 15 cities; however, the mortality rate treatment efficiency declined in 11 cities.

Microfluidic paper-based analytical devices (μPADs) are the newest generation of lab-on-a-chip devices and have made significant strides in both our understanding of fundamental behavior and performance characteristics and expansion of their applications. μPADs have become useful analytical techniques for environmental analysis in addition to their more common application as medical point-of-care devices. Although the most common method for device fabrication is wax printing, numerous other techniques exist and have helped address factors ranging from solvent compatibility to improved device function. This review highlights recent reports of fabrication and design, modes of detection, and broad applications of μPADs. Such advances have enabled μPADs to be used in field and laboratory studies to address critical needs in fast, cheaper measurement technologies.