scholarly journals Thorough Multianalytical Characterization and Quantification of Micro- and Nanoplastics from Bracciano Lake’s Sediments

2020 ◽  
Vol 12 (3) ◽  
pp. 878 ◽  
Author(s):  
Andrea Corti ◽  
Virginia Vinciguerra ◽  
Valentina Iannilli ◽  
Loris Pietrelli ◽  
Antonella Manariti ◽  
...  
Keyword(s):  
1H Nmr ◽  
Average Molecular Weight ◽  
Sampling Site ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Proton Nuclear Magnetic Resonance ◽  
Volcanic Lake ◽  
Chromatographic Detection ◽  
The Impact

Lake basins can behave as accumulators of microplastics released in wastewaters as such or resulting from degradation of larger items before and/or during their journey toward the marine environment as a final sink. A novel multianalytical approach was adopted for the detection and quantification of microplastics with size < 2 mm in the sediments of the volcanic lake of Bracciano, Italy. Simple analytical techniques such as solvent extraction/fractionation (for polyolefins and polystyrene) or depolymerization (for polyethylene terephthalate, PET), along with chromatographic detection (SEC and HPLC), allowed quantitative and qualitative determination of the main synthetic polymer contaminants. In particular, PET microplastic concentrations of 0.8–36 ppm were found, with variability related to the sampling site (exposure to incoming winds and wave action). Proton Nuclear Magnetic Resonance (1H-NMR) and Attenuated Total Reflectance Fourier Transformed InfraRed (ATR-FTIR spectroscopic investigations supported the identification and chemical characterization of plastic fragments and polymer extracts. The average molecular weight of solvent extractable polymers was evaluated from 2D 1H-NMR diffusion ordered spectroscopy (DOSY) experiments. The proposed, easily accessible multianalytical approach can be considered as a useful tool for improving our knowledge on the nature and the concentration of microplastics in sediments, giving insights on the impact of human activities on the health status of aquatic ecosystems.

Morphometric analysis of myofibre development in the adductor femoris muscle of single and twin fetal lambs

2000 ◽  
Vol 12 (6) ◽  
pp. 329 ◽  
Author(s):  
S. A. McCoard ◽  
W. C. McNabb ◽  
S. W. Peterson ◽  
S. N. McCutcheon ◽  
P. M. Harris
Keyword(s):  
Sampling Site ◽  
Muscle Growth ◽  
Morphological Characteristics ◽  
Distal Region ◽  
Fetal Life ◽  
Cross Sectional ◽  
The Impact ◽  
Femoris Muscle ◽  
Selection Of

Cellular development of the adductor femoris muscle from twin and single fetuses was studied at 140 days gestation to evaluate the effect of moderate fetal growth retardation on myofibre development. Twin fetuses had lower bodyweights (13%) and disproportionately small adductor femoris muscle weights (22%) compared with single fetuses. Reduced muscle mass was associated with smaller myofibre cross-sectional areas (CSA) and lower DNA content (22%), indicative of fewer myonuclei and retarded myofibre hypertrophy. Myofibre number and the phenotypic maturation of the myofibres were similar between twins and singletons. These results indicate that even modest growth restriction during fetal life can negatively influence myofibre hypertrophy, highlighting the importance of fetal nutrition for muscle growth. Large muscles, such as the adductor femoris, have intrafascicularly terminating myofibres, which necessitates accurate sampling of the muscle when investigating possible perturbations in morphological characteristics (e.g. between singletons and twins). The second objective of the present study was to investigate the impact of the sampling site on the morphological parameters of the adductor femoris muscle. The apparent total myofibre number decreased from the proximal to the distal region of the adductor femoris muscle. The apparent number of slow-twitch fibres also decreased from the proximal to the medial region, but was not different between the medial and distal regions of the muscle. Similarly, myofibre CSA differed between the medial and distal regions. These results indicate that, particularly with large muscles, such as the adductor femoris, which has intrafascicularly terminating myofibres, single site sampling for the determination of morphological fibre characteristics may generate misleading results and that careful selection of the sampling area may be necessary.

scholarly journals Elemental concentration via portable x-ray fluorescence spectrometry: Assessing the impact of water content

2019 ◽  
Vol 43 ◽  
Author(s):  
Monna Lysa Teixeira Santana ◽  
Geila Santos Carvalho ◽  
Luiz Roberto Guimarães Guilherme ◽  
Nilton Curi ◽  
Bruno Teixeira Ribeiro
Keyword(s):  
Water Content ◽  
Atomic Number ◽  
Certified Reference Materials ◽  
Chemical Characterization ◽  
X Ray ◽  
Influence Of Water ◽  
Corrected Data ◽  
The Impact

ABSTRACT Portable X-ray fluorescence (pXRF) analysis can be considered one of the main recent advances for chemical characterization of earth materials. The water content of the samples can affect the pXRF performance. As a novelty, we aimed to establish relationships (linear regression) between the effect of water content on pXRF results and atomic number (Z) of the elements. Three certified reference materials (CRM) were investigated: OREAS 100a, OREAS 101a, and OREAS 101b. These materials were saturated (0.68 g g-1) with distilled water and left to air-dry naturally. During the drying, the elemental concentrations (C) were determined at different water contents using a pXRF spectrometer. For each water content, the ratio Cwet/Cdry was determined and plotted against the water content. The attenuation coefficient (σ) was also determined. High σ values mean more influence of water content upon measurement element concentration. The obtained recovery rates allowed a qualitative determination. The concentration for the most elements reduced linearly with increasing water content. A predictable behavior of the water content on pXRF results as function of atomic number was not found. Elements identified by Lα spectral line with highest Z were more impacted by water content than elements identified by Kα line with lowest Z. Ti, Cr and Fe was not significantly influenced by water content, and Sr was the most impacted. Our findings contribute to decision-making before characterization earth materials via pXRF, obliging the use of dry samples for determination of impacted elements or by using moisture-corrected data.

scholarly journals Comparison of Three Methods to Determine the Degree of Substitution of Quinoa and Rice Starch Acetates, Propionates, and Butyrates: Direct Stoichiometry, FTIR, and 1H-NMR

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 83 ◽  
Author(s):  
Nabilah Abdul Hadi ◽  
Berthold Wiege ◽  
Sebastian Stabenau ◽  
Ali Marefati ◽  
Marilyn Rayner
Keyword(s):  
1H Nmr ◽  
Conformational Changes ◽  
Direct Determination ◽  
Reference Method ◽  
Degree Of Substitution ◽  
Proton Nuclear Magnetic Resonance ◽  
Rice Starch ◽  
Acid Anhydrides ◽  
Chain Lengths

Rice and quinoa starch esters were prepared by acylation using short-chain fatty acid anhydrides with different chain lengths (acetic, propionic, and butyric anhydride). A direct stoichiometric method based on the acylation reaction was used to determine the degree of substitution (DS) and acyl content (AC). In addition, Fourier-transform infrared spectroscopy (FTIR) was used to validate the conformational changes of acylated starch and 1H-NMR was used as a DS reference method. DS by stoichiometric calculation was shown to be in agreement with FTIR and was comparable with DS obtained from Proton nuclear magnetic resonance (1H-NMR). Based on this study, stoichiometric calculation allows rapid and direct determination of substitution levels and acyl content without the loss of samples, which provides efficiency and optimization of manufacturing procedures in producing the desired level of esterified starches.

scholarly journals Aqueous phase processing of secondary organic aerosol from isoprene photooxidation

2012 ◽  
Vol 12 (13) ◽  
pp. 5879-5895 ◽  
Author(s):  
Y. Liu ◽  
A. Monod ◽  
T. Tritscher ◽  
A. P. Praplan ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Signal Intensity ◽  
Secondary Organic Aerosol ◽  
Measurement Techniques ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Aging Effect ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
The Impact

Abstract. Transport of reactive air masses into humid and wet areas is highly frequent in the atmosphere, making the study of aqueous phase processing of secondary organic aerosol (SOA) very relevant. We have investigated the aqueous phase processing of SOA generated from gas-phase photooxidation of isoprene using a smog chamber. The SOA collected on filters was extracted by water and subsequently oxidized in the aqueous phase either by H2O2 under dark conditions or by OH radicals in the presence of light, using a photochemical reactor. Online and offline analytical techniques including SMPS, HR-AMS, H-TDMA, TD-API-AMS, were employed for physical and chemical characterization of the chamber SOA and nebulized filter extracts. After aqueous phase processing, the particles were significantly more hygroscopic, and HR-AMS data showed higher signal intensity at m/z 44 and a lower signal intensity at m/z 43, thus showing the impact of aqueous phase processing on SOA aging, in good agreement with a few previous studies. Additional offline measurement techniques (IC-MS, APCI-MS2 and HPLC-APCI-MS) permitted the identification and quantification of sixteen individual chemical compounds before and after aqueous phase processing. Among these compounds, small organic acids (including formic, glyoxylic, glycolic, butyric, oxalic and 2,3-dihydroxymethacrylic acid (i.e. 2-methylglyceric acid)) were detected, and their concentrations significantly increased after aqueous phase processing. In particular, the aqueous phase formation of 2-methylglyceric acid and trihydroxy-3-methylbutanal was correlated with the consumption of 2,3-dihydroxy-2-methyl-propanal, and 2-methylbutane-1,2,3,4-tetrol, respectively, and an aqueous phase mechanism was proposed accordingly. Overall, the aging effect observed here was rather small compared to previous studies, and this limited effect could possibly be explained by the lower liquid phase OH concentrations employed here, and/or the development of oligomers observed during aqueous phase processing.

scholarly journals Chemical Characterization of Vitreous Finds from Cosenza Cathedral (Calabria – Italy) by the Combined Use of Analytical Techniques

2020 ◽  
Vol 6 (1) ◽  
pp. 63-85 ◽  
Author(s):  
Donatella Barca ◽  
Franca C. Papparella
Keyword(s):  
Inductively Coupled Plasma ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Soda Lime ◽  
13Th Century ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Combined Use ◽  
Plasma Mass Spectrometry

AbstractThis article presents an archaeometrical research carried out on twenty-six vitreous finds collected in the Cosenza Cathedral (Calabria, Italy). The glasses have been subdivided in two typo-chronological groups. The first group is composed of 14 vitreous samples dating to the 4th–6th century AD. The second group includes twelve samples; seven are stems of funnel-shaped hanging lamps which date between the 12th and the 13th century AD, two are bottlenecks of balsamaria and three are concave bases. The aims of this study were the determination of the chemical composition of vitreous finds and the individuation of the primary glass sources. The samples were characterized through Electron Probe Micro Analyser with Wavelength Dispersive Spectrometer (EPMA-WDS) and Laser Ablation with Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The data confirm that all the finds of the first group are “silica-soda-lime” type glasses characterized by a high content of Na2O and a low content of K2O and MgO. On the contrary, the samples of the second group, showing higher contents of K2O and MgO, are vegetable silica-soda-lime glasses. Their composition confirms the typological attribution to the medieval period.

scholarly journals Characterizing source fingerprints and ageing processes in laboratory-generated secondary organic aerosols using proton-nuclear magnetic resonance (<sup>1</sup>H-NMR) analysis and HPLC HULIS determination

2017 ◽  
Vol 17 (17) ◽  
pp. 10405-10421 ◽  
Author(s):  
Nicola Zanca ◽  
Andrew T. Lambe ◽  
Paola Massoli ◽  
Marco Paglione ◽  
David R. Croasdale ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Flow Reactor ◽  
Analytical Techniques ◽  
Water Soluble ◽  
Proton Nuclear Magnetic Resonance ◽  
Aerosol Mass ◽  
Polycarboxylic Acids ◽  
Nuclear Magnetic

Abstract. The study of secondary organic aerosol (SOA) in laboratory settings has greatly increased our knowledge of the diverse chemical processes and environmental conditions responsible for the formation of particulate matter starting from biogenic and anthropogenic volatile compounds. However, characteristics of the different experimental setups and the way they impact the composition and the timescale of formation of SOA are still subject to debate. In this study, SOA samples were generated using a potential aerosol mass (PAM) oxidation flow reactor using α-pinene, naphthalene and isoprene as precursors. The PAM reactor facilitated exploration of SOA composition over atmospherically relevant photochemical ageing timescales that are unattainable in environmental chambers. The SOA samples were analyzed using two state-of-the-art analytical techniques for SOA characterization – proton nuclear magnetic resonance (1H-NMR) spectroscopy and HPLC determination of humic-like substances (HULIS). Results were compared with previous Aerodyne aerosol mass spectrometer (AMS) measurements. The combined 1H-NMR, HPLC, and AMS datasets show that the composition of the studied SOA systems tend to converge to highly oxidized organic compounds upon prolonged OH exposures. Further, our 1H-NMR findings show that only α-pinene SOA acquires spectroscopic features comparable to those of ambient OA when exposed to at least 1  ×  1012 molec OH cm−3  ×  s OH exposure, or multiple days of equivalent atmospheric OH oxidation. Over multiple days of equivalent OH exposure, the formation of HULIS is observed in both α-pinene SOA and in naphthalene SOA (maximum yields: 16 and 30 %, respectively, of total analyzed water-soluble organic carbon, WSOC), providing evidence of the formation of humic-like polycarboxylic acids in unseeded SOA.

scholarly journals Characterizing source fingerprints and ageing processes in laboratory-generated secondary organic aerosols using proton-nuclear magnetic resonance (<sup>1</sup>H-NMR) analysis and HPLC HULIS determination

2017 ◽  
Author(s):  
Nicola Zanca ◽  
Andrew T. Lambe ◽  
Paola Massoli ◽  
Marco Paglione ◽  
David R. Croasdale ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Flow Reactor ◽  
Maximum Yield ◽  
Analytical Techniques ◽  
Proton Nuclear Magnetic Resonance ◽  
Aerosol Mass ◽  
Polycarboxylic Acids ◽  
Nuclear Magnetic

Abstract. The study of secondary organic aerosol (SOA) in laboratory settings has greatly increased our knowledge of the diverse chemical processes and environmental conditions responsible for the formation of particulate matter starting from biogenic and anthropogenic volatile compounds. However, characteristics of the different experimental setups and the way they impact the composition and the timescale of formation of SOA are still subject to debate. In this study, SOA samples were generated using a Potential Aerosol Mass (PAM) oxidation flow reactor using alpha-pinene, naphthalene and isoprene as precursors. The PAM reactor facilitated exploration of SOA composition over atmospherically-relevant photochemical aging time scales that are unattainable in environmental chambers. The SOA samples were analyzed using two state-of-the-art analytical techniques for SOA characterization – proton nuclear magnetic resonance (1H-NMR) spectroscopy and HPLC determination of humic-like substances (HULIS). Results were compared with previous Aerodyne aerosol mass spectrometer (AMS) measurements. The combined 1H-NMR, HPLC, and AMS datasets show that the composition of the studied SOA systems tend to converge to highly oxidized organic compounds upon prolonged OH exposures. Further, our 1H-NMR findings show that only α-pinene SOA acquire spectroscopic features comparable to those of ambient OA when exposed to at least 1*1012 molec OH /cm3*s OH exposure, or multiple days of equivalent atmospheric OH oxidation. Over multiple days of equivalent atmospheric OH exposure, the formation of HULIS is observed in both α-pinene SOA (maximum yield = 16 %) and in naphthalene SOA (maximum yield = 30 %), providing evidence of the formation of humic-like polycarboxylic acids in unseeded SOA.

scholarly journals Chemical characterization and source apportionment of submicron aerosols measured in Senegal during the 2015 SHADOW campaign

2017 ◽  
Author(s):  
Laura-Hélèna Rivellini ◽  
Isabelle Chiapello ◽  
Emmanuel Tison ◽  
Marc Fourmentin ◽  
Anaïs Féron ◽  
...  
Keyword(s):  
West Africa ◽  
Source Apportionment ◽  
Sampling Site ◽  
Chemical Characterization ◽  
Sea Breeze ◽  
Saharan Dust ◽  
High Time Resolution ◽  
Organic Fraction ◽  
Air Masses ◽  
The Impact

Abstract. The present study offers the first chemical characterization of the submicron (PM1) fraction in West Africa at a high time resolution, thanks to collocated measurements of non-refractory (NR) species with an Aerosol Chemical Speciation Monitor (ACSM), black carbon and iron concentrations derived from absorption coefficient measurements with a 7-wavelength aethalometer, and total PM1 determined by a TEOM-FDMS for mass closure. The field campaign was carried out during four months (March to June 2015) as part of the SHADOW (SaHAran Dust Over West Africa) project at a coastal site located in the outskirts of the city of M'Bour, Senegal. With an average mass concentration of 5.4 µg m−3, levels of NR-PM1 in M'Bour were three to ten times lower than cities like Paris or Beijing. Nonetheless the first half of the observation period was marked by intense but short pollution events (concentrations higher than 15 µg m−3), sea breeze phenomena and Saharan desert dust outbreaks (PM10 up to 900 µg m−3). During the second half of the campaign, the sampling site was mainly under the influence of marine air masses. The air masses on days under continental and sea breeze influences were dominated by organics (36–40 %), whereas sulfate particles were predominant (40 %) for days under oceanic influence. Overall, measurements showed that about 3/4 of the total PM1 were explained by NR-PM1, BC and Fe (a proxy for dust) concentrations, leaving ~ 1/4 for other refractory species. A mean value of 4.6 % for the Fe / PM1 ratio was obtained. Source apportionment of the organic fraction, using Positive Matrix Factorization (PMF) highlighted the impact of local combustion sources, such as traffic and residential activities, which contribute on average to 52 % of the total organic fraction. A new organic aerosol (OA) source, representing on average 3 % of the total OA fraction, showed similar variation as non-refractory particulate chloride. Its rose plot and daily pattern pointed out to local combustion processes, that is to say two open waste burning areas located about 6 and 11 km away from the receptor site and to a lesser extent a traditional fish smoking place. The remaining fraction was identified as oxygenated organic aerosols (OOA), a factor that prevailed regardless of the day type (45 %) and was representative of regional but also local sources due to enhanced photochemical processes.

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