Functional group analysis of high-molecular weight compounds in the water-soluble fraction of organic aerosols

Abstract. A complete size segregated chemical characterisation was carried out for aerosol samples collected in the urban area of Bologna over a period of one year, using five-stage low pressure Berner impactors. An original dual-substrate technique was adopted to obtain samples suitable for a complete chemical characterisation. Total mass, inorganic, and organic components were analysed as a function of size, and a detailed characterisation of the water soluble organic compounds was also performed by means of a previously developed methodology, based on HPLC separation of organic compounds according to their acid character and functional group analysis by Proton Nuclear Magnetic Resonance. Chemical mass closure of the collected samples was reached to within a few percent on average in the submicron aerosol range, while a higher unknown fraction in the coarse aerosol range was attributed to soil-derived species not analysed in this experiment. Comparison of the functional group analysis results with model results simulating water soluble organic compound production by gas-to-particle conversion of anthropogenic VOCs showed that this pathway provides a minor contribution to the organic composition of the aerosol samples in the urban area of Bologna.

Download Full-text

Characterization of the organic composition of aerosols from Rondônia, Brazil, during the LBA-SMOCC 2002 experiment and its representation through model compounds

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-375-2006 ◽

2006 ◽

Vol 6 (2) ◽

pp. 375-402 ◽

Cited By ~ 214

Author(s):

S. Decesari ◽

S. Fuzzi ◽

M. C. Facchini ◽

M. Mircea ◽

L. Emblico ◽

...

Keyword(s):

Chemical Composition ◽

Biomass Burning ◽

Functional Group ◽

Group Analysis ◽

Water Soluble ◽

Total Carbon ◽

Individual Compound ◽

Model Compounds ◽

Functional Group Analysis

Abstract. The chemical composition of carbonaceous aerosols collected during the LBA-SMOCC field experiment, conducted in Rondônia, Brazil, in 2002 during the transition from the dry to the wet season, was investigated by a suite of state-of-the-art analytical techniques. The period of most intense biomass burning was characterized by high concentrations of submicron particles rich in carbonaceous material and water-soluble organic compounds (WSOC). At the onset of the rainy period, submicron total carbon (TC) concentrations decreased by about 20 times. In contrast, the concentration of supermicron TC was fairly constant throughout the experiment, pointing to a constant emission of coarse particles from the natural background. About 6–8% of TC (9–11% of WSOC) was speciated at the molecular level by GC-MS and liquid chromatography. Polyhydroxylated compounds, aliphatic and aromatic acids were the main classes of compounds accounted for by individual compound analysis. Functional group analysis by proton NMR and chromatographic separation on ion-exchange columns allowed characterization of ca. 50–90% of WSOC into broad chemical classes (neutral species/light acids/humic-like substances). In spite of the significant change in the chemical composition of tracer compounds from the dry to the wet period, the functional groups and the general chemical classes of WSOC changed only to a small extent. Model compounds representing size-resolved WSOC chemical composition for the different periods of the campaign are then proposed in this paper, based on the chemical characterization by both individual compound analysis and functional group analysis deployed during the LBA-SMOCC experiment. Model compounds reproduce quantitatively the average chemical structure of WSOC and can be used as best-guess surrogates in microphysical models involving organic aerosol particles over tropical areas affected by biomass burning.

Download Full-text

Characterization of the organic composition of aerosols from Rondônia, Brazil, during the LBA-SMOCC 2002 experiment and its representation through model compounds

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-5687-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 5687-5749 ◽

Cited By ~ 5

Author(s):

S. Decesari ◽

S. Fuzzi ◽

M. C. Facchini ◽

M. Mircea ◽

L. Emblico ◽

...

Keyword(s):

Chemical Composition ◽

Biomass Burning ◽

Functional Group ◽

Group Analysis ◽

Water Soluble ◽

Total Carbon ◽

Individual Compound ◽

Model Compounds ◽

Functional Group Analysis

Abstract. The chemical composition of carbonaceous aerosols collected during the LBA-SMOCC field experiment, conducted in Rondônia, Brazil, in 2002 during the transition from the dry to the wet season, was investigated by a suite of advanced analytical techniques. The period of most intense biomass burning was characterized by high concentrations of submicron particles rich in carbonaceous material and water-soluble organic compounds (WSOC). At the onset of the rainy period, submicron total carbon (TC) concentrations had decreased by about 20 times. In contrast, the concentration of supermicron TC was fairly constant throughout the experiment, pointing to a constant emission of coarse particles from the natural background. About 6–8% of TC (9–11% of WSOC) was speciated at the molecular level by GC-MS and liquid chromatography. Poly-hydroxylated compounds, aliphatic and aromatic acids were the main classes of compounds accounted for by individual compound analysis. Functional group analysis by proton NMR and chromatographic separation on ion-exchange columns allowed characterization of ca. 50–90% of WSOC into broad chemical classes (neutral species/light acids/humic-like substances). In spite of the significant change in the chemical composition of tracer compounds from the dry to the wet period, the functional groups and the general chemical classes of WSOC changed only to a lesser extent. Model compounds representing size-resolved WSOC chemical composition for the different periods of the campaign are then proposed in this paper, based on the chemical characterization by both individual compound analysis and functional group analysis deployed during the LBA-SMOCC experiment. Model compounds reproduce quantitatively the average chemical structure of WSOC and can be used as best-guess surrogates in microphysical models involving organic aerosol particles over tropical areas affected by biomass burning.

Download Full-text

Molecular Weight and Degree of Methoxylation in Cell Wall Polyuronide during Softening in Pear and Apple Fruit

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.117.4.600 ◽

1992 ◽

Vol 117 (4) ◽

pp. 600-606 ◽

Cited By ~ 52

Author(s):

H. Yoshioka ◽

K. Aoba ◽

Y. Kashimura

Keyword(s):

Molecular Weight ◽

Cell Wall ◽

Cell Walls ◽

Soluble Fraction ◽

Apple Fruit ◽

Water Soluble ◽

Pear Fruit ◽

Water Soluble Fraction ◽

High Degree ◽

Soluble Fractions

The concentrations of water-soluble polyuronides in apples [Malus domestica Borkh.) and pears (Pyrus communis L.) increased, but those of EDTA- and HCl-soluble polyuronides decreased during softening. Total polyuronide content decreased slightly during softening in both fruits. Depolymerization of polyuronides was observed only in the water-soluble fraction in pear fruit during softening, concomitant with an increase in polygalacturonase (PG) activity. No detectable depolymerization was observed in any of the polyuronide fractions during softening of apple fruit nor was any PG activity detected. The polyuronide fractions extracted from pear and apple cell walls contained various amounts of methoxyl groups. Polyuronides with a high degree of methoxylation were preferentially lost from EDTA- and HCl-soluble polyuronides during softening of both fruit. The water-soluble polyuronide had a lower degree of methoxylation than those lost in the EDTA- and HCl-soluble fractions. These results suggest de-esterification of polyuronides with a high degree of methoxylation rather than the depolymerization of polyuronides in the solubilization of polyuronides during ripening of apples and pears.

Download Full-text

Degradation of Pectic Polysaccharides in Pickled Green Olives

Journal of Food Protection ◽

10.4315/0362-028x-61.1.78 ◽

1998 ◽

Vol 61 (1) ◽

pp. 78-86 ◽

Cited By ~ 9

Author(s):

CORAL SÁNCHEZ-ROMERO ◽

RAFAEL GUILLÉN ◽

ANTONIA HEREDIA ◽

ANA JIMÉNEZ ◽

JUAN FERNÁNDEZ-BOLAÑOS

Keyword(s):

Molecular Weight ◽

Potassium Hydroxide ◽

Soluble Fraction ◽

Water Soluble ◽

Low Molecular Weight ◽

Pectic Polysaccharides ◽

Water Soluble Fraction ◽

Molecular Weights ◽

Extraction Agent ◽

Soluble Fractions

The changes that occur in the pectic fractions in the cell wall of olives of the Manzanilla variety (Olea europaea pomiformis) during processing (initial treatment at high pH and subsequent lactic fermentation) have been researched. After studying various conditions for fractionating the pectic polysaccharides, the most adequate were chosen, involving sequential extraction with water, imidazole-hydrochloric acid buffer, sodium carbonate, 1 M potassium hydroxide, and 4 M potassium hydroxide. In the unprocessed fruit, the fractions studied consist mainly of high-molecular-weight acidic polysaccharides (70 to 250 kDa): homogalacturonans, rhamnogalacturonans, and branched arabinans. These were found in different proportions depending on the extraction agent used. At the same time, significant amounts of relatively low-molecular-weight (10 to 10.5 kDa) neutral branched arabinans were found in the water-soluble fraction. As a result of the processing, changes occurred in the proportions of the different groups of polysaccharides in accordance with changes in their solubility characteristics. These changes were reflected in the processed fruit by (i) an increase in the neutral branched arabinans in the water-soluble fraction due to the increased presence of such polysaccharides originally found in the carbonate and 4 M KOH-soluble fractions; (ii) an increase in homogalacturonans and rhamnogalacturonans, without significant changes in molecular weights, in the imidazole-soluble fraction as a result of the increased presence of corresponding polysaccharides originally found in the carbonate-soluble and water-soluble fractions; (iii) a substantial increase in uronic acids in the 1 M potassium hydroxide-soluble fraction, preferentially as low-molecular-weight polysaccharides; and (iv) a solubilization of arabinans in the 4 M potassium hydroxide-soluble fraction.

Download Full-text

Chemical mass balance of size-segregated atmospheric aerosol in an urban area of the Po Valley, Italy

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-2-2167-2002 ◽

2002 ◽

Vol 2 (6) ◽

pp. 2167-2208 ◽

Cited By ~ 5

Author(s):

E. Matta ◽

M. C. Facchini ◽

S. Decesari ◽

M. Mircea ◽

F. Cavalli ◽

...

Keyword(s):

Urban Area ◽

Organic Compounds ◽

Functional Group ◽

Group Analysis ◽

Water Soluble ◽

Proton Nuclear Magnetic Resonance ◽

Po Valley ◽

Functional Group Analysis ◽

One Year ◽

A Minor

Abstract. A complete size segregated chemical characterisation was carried out for aerosol samples collected in the urban area of Bologna over a period of one year, using five-stage low pressure Berner impactors. An original dual-substrate technique was adopted to obtain samples suitable for a complete chemical characterisation. Total mass, inorganic, and organic components were analysed as a function of size, and a detailed characterisation of the water soluble organic compounds was also performed by means of a previously developed methodology, based on HPLC separation of organic compounds according to their acid character and functional group analysis by Proton Nuclear Magnetic Resonance. Chemical mass closure of the collected samples was reached to within a few percent on average in the submicron aerosol range, while a higher unknown fraction in the coarse aerosol range was attributed to soil-derived species not analysed in this experiment. Comparison of the functional group analysis results with model results simulating water soluble organic compound production by gas-to-particle conversion of anthropogenic VOCs showed that this pathway provides a minor contribution to the organic composition of the aerosol samples in the urban area of Bologna.

Download Full-text

CHITOSAN-BASE COAGULANTS IN COAGULATION-FLOCCULATION OF KAOLIN SUSPENSION

JURNAL KIMIA MULAWARMAN ◽

10.30872/jkm.v16i1.668 ◽

2019 ◽

Vol 16 (1) ◽

pp. 16

Author(s):

Bambang Piluharto ◽

Mufrihah Nurhayati ◽

Asnawati Asnawati

Keyword(s):

Molecular Weight ◽

Functional Group ◽

Group Analysis ◽

Natural Polymers ◽

Amino Groups ◽

Environment Friendly ◽

Kaolin Suspension ◽

Functional Group Analysis ◽

Water Treatments ◽

Different Molecular Weight

Coagulation-flocculation is one of the waste water treatments using coagulant/flocculants agent. Using coagulant/flocculants based on natural polymers were many used due to many available, renewable source, and environment friendly. One of that coagulant/flocculants was chitosan that can be produced through deacetylation of chitin. Amino groups in the chitosan structure play important role in the coagulant/flocculants process. The aim of research is using chitosan-based coagulants in the coagulation-flocculation of kaolin suspension. In here, there were two coagulants type, first, single coagulant which chitosan with different molecular weight added alone in kaolin suspension. Second, mix coagulants which chitosan aid with alum in kaolin suspension. As the result, functional group analysis showed that chitosan with different molecular weight have the same functional groups. Increasing molecular weight of chitosan increase NH2 groups and degree of deacetylation. The removing turbidity of kaolin suspension showed that increasing molecular weight chitosan increase removing turbidity of kaolin suspension. Using double coagulant (chitosan and tawas) have the removing turbidity greater than single coagulant.

Download Full-text