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Identification of cement in atmospheric particulate matter using the hybrid method of laser diffraction analysis and Raman spectroscopy
摘要： The production of cement is associated with the emissions of dust and particulate matter, nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO), heavy metals, and volatile organic compounds into the environment. People living near cement production facilities are potentially exposed to these pollutants, including carcinogens, although at lower doses than the factory workers. In this study we focused on the distribution of fine particulate matter, the composition, size patterns, and spatial distribution of the emissions from Spassk cement plant in Primorsky Krai, Russian Federation. The particulate matter was studied in wash-out from vegetation (conifer needles) using a hybrid method of laser diffraction analysis and Raman spectroscopy. The results showed that fine particulate matter (PM10 fraction) extended to the entire town and its neighbourhood. The percentage of PM10 in different areas of the town and over the course of two seasons ranged from 34.8% to 65% relative to other size fractions of particulate matter. It was further shown that up to 80% of the atmospheric PM content at some sampling points was composed of cement-containing particles. This links the cement production in Spassk-Dalny with overall morbidity of the town population and pollution of the environment.
关键词： Laser diffraction analysis,Atmospheric particulate matter,Ecology,Environmental chemistry,Environmental science,Atmospheric science,Environmental pollution,Raman spectroscopy,PM10
更新于2025-09-16 10:30:52
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Detecting and Quantifying Microplastics in Bottled Water using Fluorescence Microscopy: A New Experiment for Instrumental Analysis and Environmental Chemistry Courses
摘要： Microplastics (MPs) are small plastic particles (<5 mm in size) that are ubiquitous in the environment and have even been detected in bottled water. In this laboratory experiment, suited for instrumental or environmental chemistry classes, students detect and quantify MPs in bottled water by filtering and staining them with Nile red dye prior to utilizing fluorescence microscopy. Instrumental concepts in fluorescence spectroscopy are reinforced as students build a low-cost fluorescence microscope and use it to collect images of the fluorescing MPs for counting purposes and assessing morphology. The exercise introduces students to MP pollution, an emerging field of chemical research, and motivates and engages them helping to form connections beyond the classroom. Each group detected MPs in their bottled water, and many were surprised by how many they found. Overall, the hands-on experiment received positive feedback from students, and postexperiment assessments showed marked improvement in their understanding of the principles of fluorescence and of the growing problem of MP pollution.
关键词： Analytical Chemistry,Upper-Division Undergraduate,Collaborative/Cooperative Learning,Water/Water Chemistry,Instrumental Methods,Environmental Chemistry,Hands-On Learning/Manipulatives
更新于2025-09-12 10:27:22
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Reactive Species Detection in Biology || UV–Vis Absorption and Chemiluminescence Techniques
摘要： Spectrophotometric techniques involving ultraviolet and colorimetric detection offer a convenient way of detecting reactive species (RS) formation due to the prevalence of UV-Vis spectrophotometer in research laboratories. Conventional spectrophotometric measurement of RS exploits their unique chemical reactivity with a small organic molecule and/or enzyme that has specificity to these RS where formation (or disappearance) of absorption peak/s at a particular wavelength is observed at the UV to the visible region of the electromagnetic spectrum. Direct detection of O2 from xanthine oxidase in the past involves rapid-freeze technique using electron paramagnetic resonance (EPR) spectroscopy. At the same time, spectrophotometric detection of O2 generated from xanthine oxidase/xanthine system was also employed for the investigation of the enzymatic property of superoxide dismutase (SOD) where the O2 levels were measured through reduction of ferricytochrome c, tetranitromethane, or oxidation of epinephrine to adenochrome. Several approaches have been developed since then to improve sensitivity with the use of submicromolar probe concentration thus allowing minimal interferences of the probe on the biological process being investigated. Specificity has also been improved to increase the reaction rate of probes to certain RS through synthesis of new and innovative analogues that exploit the unique chemistry between the probe and RS. Chromophore stability was also achieved through improved molecular design, optimized experimental conditions, or addition of supramolecular reagents since chromophores impart inherent thermodynamic stability as a function of its chemical structure, solvent polarity, pH, temperature, or due to presence of oxido-reductants or other reactive substances. Improved sample preparation and high-throughput analysis were also developed in order to maximize efficiency in the measurement markers of oxidative stress and determination of antioxidant capacity (AOC) of known molecules, food, biological fluid, or tissue. Therefore, spectrophotometric techniques for RS measurement have found broad application in the fields of biomedical research, clinical chemistry, plant biology, food chemistry, environmental chemistry, radiation chemistry, pharmaceuticals, toxicology, or material science to name a few, or just simply for the investigation of RS production in simple chemical systems. However, unlike the fluorescence probes, spectrophotometric as well as most applications of chemiluminescence probes do not provide spectrospatial image of the RS localization in cells, hence, one cannot deduce the site of radical production unless multiple probes and/or inhibitors are used with varying compartmentalization property (i.e., extracellular or intracellular). For example, in the investigation of radical production in cellular NADPH oxidase, several methods had been suggested such as measurement of O2 consumption, use of SOD-ferricytochrome c and horseradish peroxidase (HRP)/inhibitable probe such as Amplex Red for extracellular O2 and H2O2, respectively, and the HPLC analysis of the 2-OH-E marker for the quantification of intracellular O2.
关键词： Clinical Chemistry,Oxidative Stress,Spectrophotometric Techniques,Environmental Chemistry,Reactive Species,Antioxidant Capacity,Biomedical Research,Chemiluminescence,Superoxide Dismutase,UV-Vis Absorption
更新于2025-09-04 15:30:14