scholarly journals Liquid-liquid phase separation in organic particles containing one and two organic species: importance of the average O:C

2018 ◽  
Author(s):  
Mijung Song ◽  
Suhan Ham ◽  
Ryan J. Andrews ◽  
Yuan You ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Cloud Condensation Nuclei ◽  
Experimental Studies ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Organic Species ◽  
Organic Particles ◽  
Almost All ◽  
Liquid Liquid Phase Separation

Abstract. Recently, experimental studies have shown that liquid-liquid phase separation (LLPS) can occur in organic particles free of inorganic salts. Most of these studies used organic particles consisting of secondary organic materials generated in environmental chambers. To gain additional insight into LLPS in organic particles free of inorganic salts, we studied LLPS in organic particles consisting of one and two commercially available organic species. For particles containing one organic species, three out of the six particle types investigated underwent LLPS. In these cases, LLPS was observed when the O:C was ≤ 0.44 and the RH was between ~ 97 and ~ 100 %. The mechanism of phase separation was likely nucleation and growth. For particles containing two organic species, thirteen out of the fifteen particle types investigated underwent LLPS. In these cases, LLPS was observed when the O:C was ≤ 0.58 and mostly when the RH was between ~ 90 and ~ 100 % RH. The mechanism of phase separation was likely spinodal decomposition. In almost all cases when LLPS was observed (for both one-component and two-component particles), the highest RH at which two liquids was observed was 100 ± 2.0 %, which has important implications for the cloud condensation nuclei (CCN) properties of these particles. These combined results provide additional evidence that LLPS needs to be considered when predicting the CCN properties of organic particles in the atmosphere.

scholarly journals Liquid–liquid phase separation in organic particles containing one and two organic species: importance of the average O : C

2018 ◽  
Vol 18 (16) ◽  
pp. 12075-12084 ◽  
Author(s):  
Mijung Song ◽  
Suhan Ham ◽  
Ryan J. Andrews ◽  
Yuan You ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Cloud Condensation Nuclei ◽  
Experimental Studies ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Organic Species ◽  
Organic Particles ◽  
Almost All ◽  
Liquid Liquid Phase Separation

Abstract. Recently, experimental studies have shown that liquid–liquid phase separation (LLPS) can occur in organic particles free of inorganic salts. Most of these studies used organic particles consisting of secondary organic materials generated in environmental chambers. To gain additional insight into LLPS in organic particles free of inorganic salts, we studied LLPS in organic particles consisting of one and two commercially available organic species. For particles containing one organic species, three out of the six particle types investigated underwent LLPS. In these cases, LLPS was observed when the O : C was  ≤ 0.44 (but not always) and the relative humidity (RH) was between  ∼ 97 % and  ∼ 100 %. The mechanism of phase separation was likely nucleation and growth. For particles containing two organic species, 13 out of the 15 particle types investigated underwent LLPS. In these cases, LLPS was observed when the O : C was  ≤ 0.58 (but not always) and mostly when the RH was between  ∼ 90 % RH and  ∼ 100 % RH. The mechanism of phase separation was likely spinodal decomposition. In almost all cases when LLPS was observed (for both one-component and two-component particles), the highest RH at which two liquids was observed was 100±2.0 %, which has important implications for the cloud condensation nuclei (CCN) properties of these particles. These combined results provide additional evidence that LLPS needs to be considered when predicting the CCN properties of organic particles in the atmosphere.

scholarly journals Liquid–liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride

2013 ◽  
Vol 13 (23) ◽  
pp. 11723-11734 ◽  
Author(s):  
Y. You ◽  
L. Renbaum-Wolff ◽  
A. K. Bertram
Keyword(s):  
Phase Separation ◽  
Sodium Chloride ◽  
Liquid Phase ◽  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Inorganic Salt ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Organic Species ◽  
Liquid Liquid Phase Separation

Abstract. As the relative humidity varies from high to low values in the atmosphere, particles containing organic species and inorganic salts may undergo liquid–liquid phase separation. The majority of the laboratory work on this subject has used ammonium sulfate as the inorganic salt. In the following we studied liquid–liquid phase separation in particles containing organics mixed with the following salts: ammonium sulfate, ammonium bisulfate, ammonium nitrate and sodium chloride. In each experiment one organic was mixed with one inorganic salt and the liquid–liquid phase separation relative humidity (SRH) was determined. Since we studied 23 different organics mixed with four different salts, a total of 92 different particle types were investigated. Out of the 92 types, 49 underwent liquid–liquid phase separation. For all the inorganic salts, liquid–liquid phase separation was never observed when the oxygen-to-carbon elemental ratio (O : C) &amp;geq; 0.8 and was always observed for O : C < 0.5. For 0.5 &amp;leq; O : C < 0.8, the results depended on the salt type. Out of the 23 organic species investigated, the SRH of 20 organics followed the trend: (NH4)2SO4 &amp;geq; NH4HSO4 &amp;geq; NaCl &amp;geq; NH4NO3. This trend is consistent with previous salting out studies and the Hofmeister series. Based on the range of O : C values found in the atmosphere and the current results, liquid–liquid phase separation is likely a frequent occurrence in both marine and non-marine environments.

scholarly journals Liquid-liquid phase separation in particles containing secondary organic material free of inorganic salts

2017 ◽  
Author(s):  
Mijung Song ◽  
Pengfei Liu ◽  
Scot T. Martin ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Organic Material ◽  
Water Saturation ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Photo Oxidation ◽  
Condensation Nucleation ◽  
The Difference ◽  
Liquid Liquid Phase Separation

Abstract. Particles containing secondary organic material (SOM) are ubiquitous in the atmosphere and play a role in climate and air quality. Recently, research has shown that liquid-liquid phase separation (LLPS) occurs at high relative humidities (RH) (greater than ~ 95 %) in α-pinene-derived SOM particles free of inorganic salts while LLPS does not occur in isoprene-derived SOM particles free of inorganic salts. We expand on these findings by investigating LLPS in SOM particles free of inorganic salts produced from ozonolysis of β-caryophyllene, ozonolysis of limonene, and photo-oxidation of toluene. LLPS was observed at greater than ~ 95 % RH in the biogenic SOM particles derived from β-caryophyllene and limonene while LLPS was not observed in the anthropogenic SOM particles derived from toluene at 290 ± 1 K. This work combined with the earlier work on LLPS in SOM particles free of inorganic salts suggests that the occurrence of LLPS in SOM particles free of inorganic salts is related to the average oxygen-to-carbon elemental ratio (O : C) of the organic material. When the average O : C is between 0.25 and 0.60, LLPS was observed, but when the average O : C was between 0.52 and 1.3, LLPS was not observed. These results help explain the difference between the hygroscopic parameter k of SOM particles measured above and below water saturation in the laboratory and field, and have implications for predicting the cloud condensation nucleation properties of SOM particles.

scholarly journals PhaSePro: the database of proteins driving liquid–liquid phase separation

2019 ◽  
Author(s):  
Bálint Mészáros ◽  
Gábor Erdős ◽  
Beáta Szabó ◽  
Éva Schád ◽  
Ágnes Tantos ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Ribosome Biogenesis ◽  
Weak Interactions ◽  
Experimental Studies ◽  
Rna Degradation ◽  
Liquid Phase Separation ◽  
General Mechanism ◽  
Open Questions ◽  
Liquid Liquid Phase Separation

Abstract Membraneless organelles (MOs) are dynamic liquid condensates that host a variety of specific cellular processes, such as ribosome biogenesis or RNA degradation. MOs form through liquid–liquid phase separation (LLPS), a process that relies on multivalent weak interactions of the constituent proteins and other macromolecules. Since the first discoveries of certain proteins being able to drive LLPS, it emerged as a general mechanism for the effective organization of cellular space that is exploited in all kingdoms of life. While numerous experimental studies report novel cases, the computational identification of LLPS drivers is lagging behind, and many open questions remain about the sequence determinants, composition, regulation and biological relevance of the resulting condensates. Our limited ability to overcome these issues is largely due to the lack of a dedicated LLPS database. Therefore, here we introduce PhaSePro (https://phasepro.elte.hu), an openly accessible, comprehensive, manually curated database of experimentally validated LLPS driver proteins/protein regions. It not only provides a wealth of information on such systems, but improves the standardization of data by introducing novel LLPS-specific controlled vocabularies. PhaSePro can be accessed through an appealing, user-friendly interface and thus has definite potential to become the central resource in this dynamically developing field.

scholarly journals Effects of molecular weight and temperature on liquid–liquid phase separation in particles containing organic species and inorganic salts

2015 ◽  
Vol 15 (3) ◽  
pp. 1351-1365 ◽  
Author(s):  
Y. You ◽  
A. K. Bertram
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Liquid Phase ◽  
Ammonium Sulfate ◽  
Atmospheric Particles ◽  
Liquid Phase Separation ◽  
Organic Species ◽  
Diffusion Rates ◽  
Measured Liquid ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric particles containing organic species and inorganic salts may undergo liquid–liquid phase separation when the relative humidity varies between high and low values. To better understand the parameters that affect liquid–liquid phase separation in atmospheric particles, we studied the effects of molecular weight and temperature on liquid–liquid phase separation in particles containing one organic species mixed with either ammonium sulfate or ammonium bisulfate. In the molecular-weight-dependent studies, we measured liquid–liquid phase separation relative humidity (SRH) in particles containing ammonium sulfate and organic species with large molecular weights (up to 1153 Da). These results were combined with recent studies of liquid–liquid phase separation in the literature to assess if molecular weight is a useful parameter for predicting SRH. The combined results, which include results from 33 different particle types, illustrate that SRH does not depend strongly on molecular weight (i.e., a clear relationship between molecular weight and SRH was not observed). In the temperature-dependent studies, we measured liquid–liquid phase separation in particles containing ammonium sulfate mixed with 20 different organic species at 244 ± 1 K, 263 ± 1 K, and 278 ± 1 K; a few particles were also studied at 290 ± 1 K. These new results were combined with previous measurements of the same particle types at 290 ± 1 K. The combined SRH data illustrate that for the organic–ammonium sulfate particles studied, the SRH does not depend strongly on temperature. At most the SRH varied by 9.7% as the temperature varied from 290 to 244 K. The high SRH values (> 65%) in these experiments may explain the lack of temperature dependence. Since water is a plasticizer, high relative humidities can lead to high water contents, low viscosities, and high diffusion rates in the particles. For these cases, unless the temperature is very low, liquid–liquid phase separation is not expected to be kinetically inhibited. The occurrence of liquid–liquid phase separation and SRH did depend strongly on temperature over the range of 290–244 K for particles containing α,4-dihydroxy-3-methoxybenzeneacetic acid mixed with ammonium bisulfate. For this particle type, a combination of low temperatures and low water content likely favored kinetic inhabitation of the liquid–liquid phase separation by slow diffusion rates in highly viscous particles. The combined results suggest that liquid–liquid phase separation is likely a common occurrence in atmospheric particles at temperatures from 244–290 K, although particles that do not undergo liquid–liquid phase separation are also likely common.

scholarly journals Liquid–liquid phase separation in particles containing secondary organic material free of inorganic salts

2017 ◽  
Vol 17 (18) ◽  
pp. 11261-11271 ◽  
Author(s):  
Mijung Song ◽  
Pengfei Liu ◽  
Scot T. Martin ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Organic Material ◽  
Water Saturation ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Photo Oxidation ◽  
Condensation Nucleation ◽  
The Difference ◽  
Liquid Liquid Phase Separation

Abstract. Particles containing secondary organic material (SOM) are ubiquitous in the atmosphere and play a role in climate and air quality. Recently, research has shown that liquid–liquid phase separation (LLPS) occurs at high relative humidity (RH) (greater than  ∼  95 %) in α-pinene-derived SOM particles free of inorganic salts, while LLPS does not occur in isoprene-derived SOM particles free of inorganic salts. We expand on these findings by investigating LLPS at 290 ± 1 K in SOM particles free of inorganic salts produced from ozonolysis of β-caryophyllene, ozonolysis of limonene, and photo-oxidation of toluene. LLPS was observed at greater than  ∼  95 % RH in the biogenic SOM particles derived from β-caryophyllene and limonene while LLPS was not observed in the anthropogenic SOM particles derived from toluene. This work combined with the earlier work on LLPS in SOM particles free of inorganic salts suggests that the occurrence of LLPS in SOM particles free of inorganic salts is related to the oxygen-to-carbon elemental ratio (O : C) of the organic material. These results help explain the difference between the hygroscopic parameter κ of SOM particles measured above and below water saturation in the laboratory and field, and have implications for predicting the cloud condensation nucleation properties of SOM particles.

scholarly journals Effects of molecular weight and temperature on liquid–liquid phase separation in particles containing organic species and ammonium sulfate

2014 ◽  
Vol 14 (16) ◽  
pp. 23341-23373
Author(s):  
Y. You ◽  
A. K. Bertram
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Liquid Phase ◽  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Atmospheric Particles ◽  
Liquid Phase Separation ◽  
Organic Species ◽  
Measured Liquid ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric particles containing organic species and inorganic salts may undergo liquid–liquid phase separation when the relative humidity varies between high and low values. To better understand the parameters that affect liquid–liquid phase separation in atmospheric particles, we studied the effects of molecular weight and temperature on liquid–liquid phase separation in particles containing one organic species mixed with ammonium sulfate. In the molecular weight dependent studies, we measured liquid–liquid phase separation relative humidity (SRH) in particles containing ammonium sulfate and organic species with large molecular weights (up to 1153 Da). These results were combined with recent studies of liquid–liquid phase separation in the literature to assess if molecular weight is a useful parameter for predicting SRH. The combined results, which include results from 33 different particle types, illustrate that SRH does not depend strongly on molecular weight (i.e. a clear relationship between molecular weight and SRH was not observed). In the temperature dependent studies, we measured liquid–liquid phase separation in 20 particle types at 244 ± 1 K, 263 ± 1 K, and 278 ± 1 K, as well as 290 ± 1 K for a few of these particle types. These new results were combined with previous measurements of the same particle types at 290 ± 1 K. The combined SRH data illustrate that for the particle types studied the SRH does not depend strongly on temperature. At most the SRH varied by 9.7% as the temperature varied from 290 to 244 K. In addition, for all the particle types studied and at all the temperatures studied, liquid–liquid phase separation was always observed when the O : C < 0.57, frequently observed when 0.57 ≤ O : C < 0.8, and never observed when O : C ≥ 0.8. These combined results suggest that liquid–liquid phase separation is likely a common occurrence in the atmospheric particles at temperatures from 244–290 K. Additional studies at temperatures < 244 K and with other organic species are still needed.

scholarly journals Water uptake of subpollen aerosol particles: hygroscopic growth, cloud condensation nuclei activation, and liquid–liquid phase separation

2021 ◽  
Vol 21 (9) ◽  
pp. 6999-7022
Author(s):  
Eugene F. Mikhailov ◽  
Mira L. Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey S. Vlasenko ◽  
Ovid O. Krüger ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Cloud Condensation Nuclei ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Differential Mobility Analyzer ◽  
Condensation Nuclei ◽  
Differential Mobility ◽  
Liquid Liquid Phase Separation

Abstract. Pollen grains emitted from vegetation can release subpollen particles (SPPs) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPPs. A high-humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both subsaturated and supersaturated conditions, effective hygroscopicity parameters, κ, were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPPs from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited a sharp increase of water uptake and κ above ∼95 % RH, suggesting a liquid–liquid phase separation (LLPS). The HHTDMA measurements at RH >95 % enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when hygroscopicity tandem differential mobility analyzer (HTDMA) measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPPs.

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