scholarly journals Solid-phase excitation-emission matrix spectroscopy for chemical analysis of combustion aerosols

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251664
Author(s):  
Gaurav Mahamuni ◽  
Jiayang He ◽  
Jay Rutherford ◽  
Byron Ockerman ◽  
Arka Majumdar ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Cigarette Smoke ◽  
Forest Fires ◽  
Solid Phase ◽  
Organic Fraction ◽  
Excitation Light ◽  
Excitation Emission Matrix ◽  
Internal Excitation ◽  
Combustion Aerosols

Exposure to ultrafine combustion aerosols such as particulate matter (PM) from residential woodburning, forest fires, cigarette smoke, and traffic emission have been linked to adverse health outcomes. Excitation-emission matrix (EEM) spectroscopy presents a sensitive and cost-effective alternative for analysis of PM organic fraction. However, as with other analytical chemistry methods, the miniaturization is hindered by a solvent extraction step and a need for benchtop instrumentation. We present a methodology for collecting and in-situ analysis of airborne nanoparticles that eliminates labor-intensive sample preparation and miniaturizes the detection platform. Nanoparticles are electrostatically collected onto a transparent substrate coated with solid-phase (SP) solvent—polydimethylsiloxane (PDMS). The PM organic fraction is extracted into PDMS and analyzed in-situ, thus avoiding liquid-phase extraction. In the SP-EEM analysis, we evaluated external and internal excitation schemes. Internal excitation shows the lowest scattering interference but leads to signal masking from PDMS fluorescence for λ<250nm. The external excitation EEM spectra are dependent on the excitation light incident angle; ranges of 30–40° and 55–65° show the best results. SP-EEM spectra of woodsmoke and cigarette smoke samples are in good agreement with the EEM spectra of liquid-phase extracts. The SP-EEM technique can be used to develop wearable sensors for exposure assessments and environmental monitoring.

Solid Phase Excitation-Emission Matrix Spectroscopy for In-Situ Chemical Analysis of Combustion Aerosols

2020 ◽  
Author(s):  
Gaurav Mahamuni ◽  
Jiayang He ◽  
Jay Rutherford ◽  
Byron Ockerman ◽  
Edmund Seto ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Cigarette Smoke ◽  
Forest Fires ◽  
Solid Phase ◽  
Incident Angle ◽  
Personal Exposure ◽  
Traffic Emission ◽  
Excitation Emission Matrix ◽  
Internal Excitation

<p>Exposure to combustion generated aerosols such as PM from residential woodburning, forest fires, cigarette smoke, and traffic emission have been linked to adverse health outcomes. It is important to assess the chemical composition of PM to examine personal exposure. Excitation-emission matrix (EEM) spectroscopy has been shown as a sensitive and cost-effective technique for evaluation of combustion PM composition and as a source apportionment tool. However, EEM measurements are hindered by a solvent extraction step and a need for benchtop instrumentation. Here, we present a methodology that eliminates this labor-intensive sample preparation and allows to automate and miniaturize the detection platform. A miniature electrostatic collector deposits PM sample onto transparent polydimethylsiloxane (PDMS) coated substrate, where PAH components are extracted into solid-phase (SP) solvent and analyzed using EEM spectroscopy in-situ. We evaluated external and internal excitation schemes to optimized signal to noise ratio. Analysis of woodsmoke and cigarette smoke samples showed good agreement with liquid extraction EEM spectra. Internal excitation is hindered by fluorescent interference from PDMS at λ<250nm. The external excitation EEM spectra are dependent on the incident angle; ranges of 30-40⁰ and 55-65⁰ showed the best results. The proposed SP-EEM technique can be used for development of miniaturized sensors for chemical analysis of combustion generated PM. </p>

Solid Phase Excitation-Emission Matrix Spectroscopy for In-Situ Chemical Analysis of Combustion Aerosols

2020 ◽  
Author(s):  
Gaurav Mahamuni ◽  
Jiayang He ◽  
Jay Rutherford ◽  
Byron Ockerman ◽  
Edmund Seto ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Cigarette Smoke ◽  
Forest Fires ◽  
Solid Phase ◽  
Incident Angle ◽  
Personal Exposure ◽  
Traffic Emission ◽  
Excitation Emission Matrix ◽  
Internal Excitation

<p>Exposure to combustion generated aerosols such as PM from residential woodburning, forest fires, cigarette smoke, and traffic emission have been linked to adverse health outcomes. It is important to assess the chemical composition of PM to examine personal exposure. Excitation-emission matrix (EEM) spectroscopy has been shown as a sensitive and cost-effective technique for evaluation of combustion PM composition and as a source apportionment tool. However, EEM measurements are hindered by a solvent extraction step and a need for benchtop instrumentation. Here, we present a methodology that eliminates this labor-intensive sample preparation and allows to automate and miniaturize the detection platform. A miniature electrostatic collector deposits PM sample onto transparent polydimethylsiloxane (PDMS) coated substrate, where PAH components are extracted into solid-phase (SP) solvent and analyzed using EEM spectroscopy in-situ. We evaluated external and internal excitation schemes to optimized signal to noise ratio. Analysis of woodsmoke and cigarette smoke samples showed good agreement with liquid extraction EEM spectra. Internal excitation is hindered by fluorescent interference from PDMS at λ<250nm. The external excitation EEM spectra are dependent on the incident angle; ranges of 30-40⁰ and 55-65⁰ showed the best results. The proposed SP-EEM technique can be used for development of miniaturized sensors for chemical analysis of combustion generated PM. </p>

Microstructure and Properties of In Situ Fabricated Al-5wt.%Si-Al2O3 Composites

2012 ◽  
Vol 567 ◽  
pp. 15-20 ◽  
Author(s):  
Ling Cheng ◽  
De Gui Zhu ◽  
Ying Gao ◽  
Wei Li ◽  
Bo Wang
Keyword(s):  
Shear Strength ◽  
Liquid Phase ◽  
Solid Phase ◽  
Hold Time ◽  
Aluminum Matrix ◽  
Liquid Phase Sintering ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
X Ray

Alumina reinforced aluminum matrix composites (Al-5wt.%Si-Al2O3) fabricated by powder metallurgy through hot isotactic pressing were sintered in different processes, i.e. solid and liquid phase sintering. Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) techniques were used to characterize the sintered composites. The effects of solid phase and liquid phase sintering on density, microstructure, microhardness, compression and shear strength were investigated. It was found that in situ chemical reaction was completed in solid phase sintering, but the composites had lower microhardness, comprehension and shear strength due to low density and segregation of alumina and Si particles in microstructure. Segregation of reinforcement particles in solid phase sintering resulted from character of solid reaction and Si diffusion at high temperature over a long hold time.

In Situ Observation of Semisolid Fe-2.5C-1.5Si Gray Cast Iron

2016 ◽  
Vol 256 ◽  
pp. 63-68
Author(s):  
Davi Munhoz Benati ◽  
Kazuhiro Ito ◽  
Kazuyuki Kohama ◽  
Hajime Yamamoto ◽  
Eugênio José Zoqui
Keyword(s):  
Cast Iron ◽  
Liquid Phase ◽  
Laser Scanning ◽  
Gray Cast Iron ◽  
Solid Phase ◽  
Laser Scanning Confocal Microscopy ◽  
Raw Material ◽  
Gray Cast ◽  
Heating Process

Fe-2.5C-1.5Si gray cast iron evaluated in previous works exhibited promising potential as semisolid raw material presenting low levels of maximum stress and viscosity, similar to Al-Si alloys. This work is intended to investigate phase transformations and liquid phase formation for the Fe-2.5C-1.5Si gray cast iron in order to understand the performance of the alloy during the semisolid processing. Thus in situ heating experiments via high temperature laser scanning confocal microscopy were performed to analyze the solid-to-liquid transition. At room temperature alloy presented a matrix of pearlite and ferrite with type D flake graphite. During the heating process the main transformations observed were graphite precipitation on the austenite grain boundaries, graphite precipitates and flakes graphite growing and coarsening with the increasing of temperature and the beginning of melt around 1140°C. Coarsened flakes at high temperatures resulted in a liquid continuous network after melting, thereby the liquid phase was formed surrounding and wetting homogeneously the solid phase. This favors the detachment of grains from each other and leads to the intended solid globules immersed in liquid.

scholarly journals Removal of Pb from Water: the Effectiveness of Gypsum and Calcite Mixtures

2020 ◽  
Author(s):  
Ana Roza Llera ◽  
Amalia Jimenez ◽  
Lurdes Fernández-Díaz
Keyword(s):  
Liquid Phase ◽  
Solid Phase ◽  
Mineral Surfaces ◽  
Atmospheric Conditions ◽  
Long Term Effects ◽  
Anthropogenic Lead ◽  
Living Organisms

Anthropogenic lead pollution is an environmental problem that threatens the quality of soils and waters and endangers living organisms in numerous surface and subsurface habitats. Lead coprecipitation on mineral surfaces through dissolution-recrystallization processes has long term effects on lead bioavailability. Gypsum and calcite are among the most abundant and reactive rock forming minerals present in numerous geological settings. In this work, we study the interaction of slightly acidic (pHi = 5.5) Pb-bearing aqueous solutions ([Pb]i = 1 mM and 10 mM) with crystals of gypsum and /or calcite under atmospheric conditions. This interaction results in a reduction of the concentration of lead in the liquid phase due to the precipitation of newly formed Pb-bearing solid phases. The extent of this Pb removal mainly depends on the nature of the primary mineral phase involved in the interaction. Thus, when gypsum is the only solid phase initially present in the system the Pb-bearing liquid-gypsum interaction results in Pb removals in the 98-99.8 % range, regardless of [Pb]i. In contrast, when the interaction takes place with calcite, Pb removal strongly depends on [Pb]i. It reaches 99% when [Pb]i = 1 mM while it is much more modest (⁓13%) when [Pb]i = 10 mM. Interestingly, Pb-removal is maximized for both [Pb]i (99.9 % for solutions with [Pb]i = 10 mM and 99.7% for solutions with [Pb]i = 1 mM) when Pb-polluted solutions simultaneously interact with gypsum and calcite crystals. Despite the large Pb removals found in most of the cases studied, the final Pb concentration ([Pb]f) in the liquid phase always is well above the maximum permitted in drinking water (0.1 ppm), with the minimum ([Pb]f = 0.7 ppm) being obtained for solutions with [Pb]i =1 mM after their interaction with mixtures of gypsum and calcite crystals. This result suggests that integrating the use of mixtures of gypsum-calcite crystals might help to develop more efficient strategies for in-situ decontaminating Pb-polluted waters through mineral coprecipitation processes.

scholarly journals Removal of Pb from Water: The Effectiveness of Gypsum and Calcite Mixtures

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 66
Author(s):  
Ana Roza Llera ◽  
Amalia Jimenez ◽  
Lurdes Fernández-Díaz
Keyword(s):  
Liquid Phase ◽  
Solid Phase ◽  
Mineral Surfaces ◽  
Atmospheric Conditions ◽  
Long Term Effects ◽  
Anthropogenic Lead ◽  
Living Organisms

Anthropogenic lead pollution is an environmental problem that threatens the quality of soils and waters and endangers living organisms in numerous surface and subsurface habitats. Lead coprecipitation on mineral surfaces through dissolution-recrystallization processes has long-term effects on lead bioavailability. Gypsum and calcite are among the most abundant and reactive rock forming minerals present in numerous geological settings. In this work, we studied the interaction of slightly acidic (pHi = 5.5) Pb-bearing aqueous solutions ([Pb]i = 1 and 10 mM) with crystals of gypsum and/or calcite under atmospheric conditions. This interaction resulted in a reduction of the concentration of lead in the liquid phase due to the precipitation of newly formed Pb-bearing solid phases. The extent of this Pb removal mainly depended on the nature of the primary mineral phase involved in the interaction. Thus, when gypsum was the only solid phase initially present in the system, the Pb-bearing liquid-gypsum interaction resulted in Pb removals in the 98–99.8% range, regardless of [Pb]i. In contrast, when the interaction took place with calcite, Pb removal strongly depended on [Pb]i. It reached 99% when [Pb]i = 1 mM, while it was much more modest (~13%) when [Pb]i = 10 mM. Interestingly, Pb-removal was maximized for both [Pb]i (99.9% for solutions with [Pb]i = 10 mM and 99.7% for solutions with [Pb]i = 1 mM) when Pb-polluted solutions simultaneously interacted with gypsum and calcite crystals. Despite the large Pb removals found in most of the cases studied, the final Pb concentration ([Pb]f) in the liquid phase was always well above the maximum permitted in drinking water (0.01 ppm), with the minimum ([Pb]f = 0.7 ppm) being obtained for solutions with [Pb]i = 1 mM after their interaction with mixtures of gypsum and calcite crystals. This result suggests that integrating the use of mixtures of gypsum-calcite crystals might help to develop more efficient strategies for in-situ decontaminating Pb-polluted waters through mineral coprecipitation processes.

Preparation and Properties of Injectable Hydroxyapatite for Bone Repair Materials

2010 ◽  
Vol 434-435 ◽  
pp. 590-593
Author(s):  
Hua Liu ◽  
Xiao Feng Chen ◽  
Chang Ren Zhou
Keyword(s):  
Liquid Phase ◽  
Bone Repair ◽  
Solid Phase ◽  
Setting Time ◽  
Chitosan Solution ◽  
Hydration Reaction ◽  
Liquid Ratio ◽  
Repair Materials ◽  
Bone Repair Materials

The aim of this study was to develop a novel injectable hydroxyapatite for bone repair materials. This study was based on the in situ setting properties of calcium phosphate cement (CPC), which properties were improved. The solid phase consisted of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA). The liquid phase was the weak acidic solution of chitosan. The CPC powder was mixed with the chitosan solution to form a paste that could conform to the bone cavity even for irregularly shaped cavities. All the by-production disappeared by neutralization reaction. The CPC paste could then set in situ to form hydroxyapatite (HA) as the final product. The chemical process of CPC hydration was studied. The process was controlled by dissolution and precipitation chemical reaction. The kinetic model of hydration reaction was established. The effects of preparing conditions, such as powder to liquid ratio and particle size, on setting time and compressive strength were investigated systematically. The optimal condition was that the liquid phase contained 3% chitosan, 5% citric acid and 15% glucose (wt%), powder to liquid ratio was 0.8 g/ml, and powders were respectively ground for 40 hours.

Identification of hepatitis a virus in cell cultures by solid phase immune electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 238-239
Author(s):  
C.D. Humphrey ◽  
T.L. Cromeans ◽  
E.H. Cook ◽  
D.W. Bradley
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
Cell Cultures ◽  
Rapid Detection ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Immune Electron Microscopy ◽  
Detection And Identification

There is a variety of methods available for the rapid detection and identification of viruses by electron microscopy as described in several reviews. The predominant techniques are classified as direct electron microscopy (DEM), immune electron microscopy (IEM), liquid phase immune electron microscopy (LPIEM) and solid phase immune electron microscopy (SPIEM). Each technique has inherent strengths and weaknesses. However, in recent years, the most progress for identifying viruses has been realized by the utilization of SPIEM.

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