scholarly journals Development of an online-coupled MARGA upgrade for the 2 h interval quantification of low-molecular-weight organic acids in the gas and particle phases

2019 ◽  
Vol 12 (1) ◽  
pp. 281-298 ◽  
Author(s):  
Bastian Stieger ◽  
Gerald Spindler ◽  
Dominik van Pinxteren ◽  
Achim Grüner ◽  
Markus Wallasch ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Acids ◽  
Gas Phase ◽  
Solid Phase ◽  
Methanesulfonic Acid ◽  
Ambient Air ◽  
Gradient Elution ◽  
Low Molecular Weight ◽  
Gradient System ◽  
Separation Columns

Abstract. A method is presented to quantify the low-molecular-weight organic acids such as formic, acetic, propionic, butyric, pyruvic, glycolic, oxalic, malonic, succinic, malic, glutaric, and methanesulfonic acid in the atmospheric gas and particle phases, based on a combination of the Monitor for AeRosols and Gases in ambient Air (MARGA) and an additional ion chromatography (Compact IC) instrument. Therefore, every second hourly integrated MARGA gas and particle samples were collected and analyzed by the Compact IC, resulting in 12 values per day for each phase. A proper separation of the organic target acids was initially tackled by a laboratory IC optimization study, testing different separation columns, eluent compositions and eluent flow rates for both isocratic and gradient elution. Satisfactory resolution of all compounds was achieved using a gradient system with two coupled anion-exchange separation columns. Online pre-concentration with an enrichment factor of approximately 400 was achieved by solid-phase extraction consisting of a methacrylate-polymer-based sorbent with quaternary ammonium groups. The limits of detection of the method range between 0.5 ng m−3 for malonate and 17.4 ng m−3 for glutarate. Precisions are below 1.0 %, except for glycolate (2.9 %) and succinate (1.0 %). Comparisons of inorganic anions measured at the TROPOS research site in Melpitz, Germany, by the original MARGA and the additional Compact IC are in agreement with each other (R2 = 0.95–0.99). Organic acid concentrations from May 2017 as an example period are presented. Monocarboxylic acids were dominant in the gas phase with mean concentrations of 306 ng m−3 for acetic acid, followed by formic (199 ng m−3), propionic (83 ng m−3), pyruvic (76 ng m−3), butyric (34 ng m−3) and glycolic acid (32 ng m−3). Particulate glycolate, oxalate and methanesulfonate were quantified with mean concentrations of 26, 31 and 30 ng m−3, respectively. Elevated concentrations of gas-phase formic acid and particulate oxalate in the late afternoon indicate photochemical formation as a source.

scholarly journals Development of an online-coupled MARGA upgrade for the two-hourly quantification of low-molecular weight organic acids in the gas and particle-phase

2018 ◽  
Author(s):  
Bastian Stieger ◽  
Gerald Spindler ◽  
Dominik van Pinxteren ◽  
Achim Grüner ◽  
Markus Wallasch ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Acids ◽  
Organic Acid ◽  
Gas Phase ◽  
Solid Phase ◽  
Ambient Air ◽  
Low Molecular Weight ◽  
Gradient System ◽  
Particle Phase ◽  
Separation Columns

Abstract. A method is presented to quantify the low-molecular weight organic acids formic, acetic, propionic, butyric, pyruvic, glycolic, oxalic, malonic, succinic, malic, glutaric, and methanesulfonic acid in the atmospheric gas and particle phase in a two-hourly time resolution, based on a combination of the Monitor for AeRosols and Gases in ambient Air (MARGA) and an additional ion chromatography (IC) instrument. A proper separation of the organic target acids was initially tackled by a laboratory IC optimization study, testing different separation columns, eluent compositions and eluent flow rates both for isocratic and for gradient elution. Satisfactory resolution of all compounds was achieved using a gradient system with two coupled anion exchange separation columns. Online pre-concentration with an enrichment factor of approximately 400 was achieved by solid phase extraction consisting of a methacrylate polymer based sorbent with quaternary ammonium groups. The limits of detection of the method range between 7.1 ng m−3 for methanesulfonate and 150.3 ng m−3 for pyruvate. Precisions are below 1.0 %, except for glycolate (2.9 %) and succinate (1.0 %). Comparisons of inorganic anions measured at the TROPOS research site in Melpitz, Germany, by the original MARGA and the additional organic acid IC systems are in agreement with each other (R2 = 0.95 − 0.99). Organic acid concentrations from May 2017 as an example period are presented. Monocarboxylic acids were dominant in the gas phase with mean concentrations of 553 ng m−3 for acetic acid, followed by formic (286 ng m−3), pyruvic acid (182 ng m−3), propionic (179 ng m−3), butyric (98 ng m−3) and glycolic (71 ng  m−3). Particulate glycolate, oxalate and methanesulfonate were quantified with mean concentrations of 63 ng  m−3, 74 ng m−3 and 35 ng m−3, respectively. Elevated concentrations in the late afternoon of gas phase formic acid and particulate oxalate indicate a photochemical formation.

Strong deviations from thermodynamically expected phase partitioning of organic acids during one year of rural field measurements 

2021 ◽  
Author(s):  
Andreas Tilgner ◽  
Bastian Stieger ◽  
Dominik van Pinxteren ◽  
Gerald Spindler ◽  
Laurent Poulain ◽  
...  
Keyword(s):  
Organic Acids ◽  
Gas Phase ◽  
Methanesulfonic Acid ◽  
Field Measurements ◽  
Ambient Air ◽  
Water Soluble ◽  
Particle Phase ◽  
Organic Salts ◽  
Phase Partitioning ◽  
One Year

<p>Organic acids are ubiquitous compounds in the troposphere and can affect human health, the climate, air quality, and the linked ecosystems. Depending on their solubility and volatility, they can partition in both gas phase and in the particle phase. In the particle phase, organic acids partly represent about 10% of the water-soluble organic matter. However, their partitioning between different phases is not fully understood yet. Therefore, an upgraded monitor for aerosols and gases in ambient air (MARGA) was applied for one year at the Central European TROPOS research site Melpitz to study the gas- and particle-phase partitioning of formic, acetic, propionic, butyric, glycolic, pyruvic, oxalic, malonic, succinic, malic, and methanesulfonic acid (MSA). Measured gas- and PM<sub>10</sub> particle-phase mean concentrations were 12−445 and 7−31 ng m<sup>-3</sup> for monocarboxylic acids (MCAs), between 0.6−8 and 4−31 ng m<sup>-3</sup> for dicarboxylic acids (DCAs), and 2 and 31 ng m<sup>-3</sup> for MSA, respectively. Assuming full dissolution in nonideal aerosol solutions, empirical noneffective Henry’s law constants (H<sub>emp</sub>) were calculated and compared with literature values (H<sub>lit</sub>). Calculated mean H<sub>emp</sub> were 4.5 × 10<sup>9</sup>−2.2 × 10<sup>10</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for MCAs, 3.6 × 10<sup>10</sup>−7.5 × 10<sup>11</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for DCAs, and 7.5 × 10<sup>7</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for MSA and, thus, factors of 5.1 × 10<sup>3</sup>−9.1 × 10<sup>5</sup> and 2.5−20.3 higher than their corresponding H<sub>lit</sub> for MCAs and DCAs, respectively, and 9.0 × 10<sup>−5</sup> lower than H<sub>lit,MSA</sub>. Data analyses and thermodynamic calculations implicate that the formation of chemical association complexes and organic salts inhibits the partitioning of organic acids toward the gas phase and, thus, at least partly explains higher H<sub>emp</sub> values for both MCAs and summertime DCAs. Low H<sub>emp,MSA</sub> are also unexpected because of the high MSA solubility and are reported for the first time in this study. Overall, the results of the present study implicate that processes responsible for the observed stronger partitioning of carboxylic acids toward the particle phase need to be further investigated and accounted for in complex multiphase chemistry models as they affect the contribution of organic acids to secondary organic aerosol mass, their chemical processing, and lifetime.</p> <p> </p> <p> </p>

Effective solid phase extraction using centrifugation combined with a vacuum-based method for ambient gaseous PAHs

2019 ◽  
Vol 43 (47) ◽  
pp. 18726-18740
Author(s):  
Wittaya Tala ◽  
Somporn Chantara
Keyword(s):  
Molecular Weight ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Ambient Air ◽  
Low Molecular Weight ◽  
Phase Extraction ◽  
Air Samples ◽  
Conventional Procedure

The developed SPE clean-up procedure provides much better efficiency for a group of low molecular weight PAHs than the conventional procedure. It is therefore appropriate for extraction of gaseous PAHs from ambient air samples.

scholarly journals INFLUENCE OF VARIOUS FEED ADDITIVES ON THE ACTIVITY OF CHYME AND BLOOD PLASMA ENZYMES OF YOUNG MEAT CHICKEN OF ORIGINAL LINE

THE BULLETIN ◽  
2021 ◽  
Vol 2 (390) ◽  
pp. 12-17
Author(s):  
A. Grozina
Keyword(s):  
Molecular Weight ◽  
Organic Acids ◽  
Blood Plasma ◽  
Digestive Enzymes ◽  
Feed Additives ◽  
Pancreatic Enzymes ◽  
Control Group ◽  
Physiological Status ◽  
Low Molecular Weight ◽  
Original Line

The research aimed to determine the effect of a mixture of low molecular weight organic acids and complex phytobiotics when replacing a feed antibiotic with them on the activity of digestive enzymes in the duode-nal chyme and the activity of pancreatic enzymes in the blood plasma of young stock B5 and B9 meat chicken lines. The experiments were carried out on the original lines of meat poultry lines B5 (Cornish) and B9 (Plymouth rock). There was an operation to insert a cannula into the duodenum at the age of 6 weeks. The enzymatic activity of the duodenum chyme and the content of pancreatic enzymes in the blood plasma in the groups of chickens receiving antibiotics, low molecular weight organic acids, and phytobiotics with the diet. The data showed that the influence of feed additives on the physiological status of poultry was different. The use of low molecular weight organic acids of the B5 and B9 chicken lines had a significant effect on the production of digestive enzymes due to an increase in the activity of chyme lipase (by 98.3%) and blood plasma lipase (by 26.6%) in B9 chickens and an increase in chyme proteases (by 30.9%) in B5 chickens compared with the control group, where the antibiotic was used. The introduction of complex phytobiotics into the diet had a negative effect on chickens of the B5 line (Cornish), reducing the activity of amylase and lipase of the duodenal chyme (by 29.2 and 26.9%) compared with the control group. In B9 (Plymouth rock) chickens, only the chyme amylase activity increased by 30.8% that indicates an improvement in the availability of feed carbohydrates. These data confirm the need to take into account the different effects of feed additives on the digestion processes in different poultry crosses.

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