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Sensors (Basel, Switzerland) Feb 2022The measurement of air quality parameters for indoor environments is of increasing importance to provide sufficient safety conditions for workers, especially in places...
The measurement of air quality parameters for indoor environments is of increasing importance to provide sufficient safety conditions for workers, especially in places including dangerous chemicals and materials such as laboratories, factories, and industrial locations. Indoor air quality index (IAQ-index) and total volatile organic Compounds (TVOC) are two important parameters to measure air impurities or air pollution. Both parameters are widely used in gases sensing applications. In this paper, the IAQ-index and TVOCs have been investigated to identify the best and most flexible solution for air quality threshold selection of hazardous/toxic gases detection and alarming systems. The TVOCs from the SGP30 gas sensor and the IAQ-index from the SGP40 gas sensor were tested with 12 different organic solvents. The two gas sensors are combined with an IoT-based microcontroller for data acquisition and data transfer to an IoT-cloud for further processing, storing, and monitoring purposes. Extensive tests of both sensors were carried out to determine the minimum detectable volume depending on the distance between the sensor node and the leakage source. The test scenarios included static tests in a classical chemical hood, as well as tests with a mobile robot in an automated sample preparation laboratory with different positions.
Topics: Air Pollutants; Air Pollution, Indoor; Environmental Monitoring; Gases; Humans; Laboratories; Volatile Organic Compounds
PubMed: 35214376
DOI: 10.3390/s22041473 -
Data in Brief Dec 2021In the municipal context and depending on the collection scheme, different waste streams are of relevance. This article contains year-round data on the chemical...
In the municipal context and depending on the collection scheme, different waste streams are of relevance. This article contains year-round data on the chemical composition of organic fractions of municipal solid waste (OFMSW) of rural and urban origins. All samples were collected in the municipality of Tübingen, which is located in southern Germany. The sampling procedure was executed in accordance with standard procedures mentioned in the German Biowaste Ordinance. The data presented in this article include (1) sampling area and process specifications (2) organoleptic examinations (3) dry matter and organic dry matter contents (4) impurity concentrations and (5) elemental compositions (major, minor and trace elements). All datasets are presented as a time series for the year 2018. Thus, this article especially presents the influence of season and settlement structure on the physico-chemical characteristics of OFMSW. Researchers, waste management companies and municipalities can compare and expand their own OFMSW data with those presented in this article. The dataset can also be used to calculate energy yields of OFMSW when utilized in anaerobic digestion. Based on the data, it is also possible to discuss and to evaluate the material utilization of OFMSW-based digestates and compost products, especially with regard to concentrations of major, minor and trace elements. For further discussion, please refer to the original scientific article Sailer et al. (2021).
PubMed: 34820489
DOI: 10.1016/j.dib.2021.107543 -
Science Advances May 2021Pure organic persistent room temperature phosphorescence (RTP) has shown great potential in information encryption, optoelectronic devices, and bio-applications....
Pure organic persistent room temperature phosphorescence (RTP) has shown great potential in information encryption, optoelectronic devices, and bio-applications. However, trace impurities are generated in synthesis, causing unpredictable effects on the luminescence properties. Here, an impurity is isolated from a pure organic RTP system and structurally characterized that caused an unusual ultralong RTP in matrix even at 0.01 mole percent content. Inspired by this effect, a series of compounds are screened out to form the bicomponent RTP system by the trace ingredient incorporation method. The RTP quantum yields reach as high as 74.2%, and the lifetimes reach up to 430 ms. Flexible application of trace ingredients to construct RTP materials has become an eye-catching strategy with high efficiency, economy, and potential for applications as well as easy preparation.
PubMed: 33962952
DOI: 10.1126/sciadv.abf9668 -
MSphere Oct 2019Gellan gum is a microbial exopolysaccharide, produced after aerobic fermentation using the Gram-negative bacterium strain ATCC 31461. Due to its unique structure and...
Gellan gum is a microbial exopolysaccharide, produced after aerobic fermentation using the Gram-negative bacterium strain ATCC 31461. Due to its unique structure and excellent physical characteristics, gellan gum has a broad range of applications in food, pharmaceutical, and other industries where it is used for stabilizing, emulsifying, thickening, and suspending. During the fermentative production of gellan, strain ATCC 31461 also accumulates large amounts of the metabolic by-products yellow carotenoid pigments and poly-β-hydroxybutyrate (PHB), which is decreasing the gellan production and increasing processing costs. A pigment PHB-free mutant was obtained by knocking out the phytoene desaturase gene () in the carotenoid biosynthetic pathway and the gene, encoding a PHB synthase for the polymerization of PHB. Unfortunately, the double gene knockout mutant produced only 0.56 g liter gellan. Furthermore, blocking PHB and carotenoid synthesis resulted in the accumulation of pyruvate, which reduced gellan production. To elevate gellan production, combined UV irradiation and ethyl methanesulfonate (EMS) mutagenesis treatment were used. A mutant strain with the same level of pyruvate as that of the wild-type strain and higher gellan production was isolated (1.35 g liter, 132.8% higher than the double gene knockout mutant and 14.4% higher than the wild-type strain ATCC 31461). In addition, a new gellan gum recovery method based on the new mutant strain was investigated, in which only 30% isopropanol was required, which is twice for the wild-type strains, and the performance of the final product was improved. Thus, the mutant strain could be an ideal strain for the commercial production of gellan. A carotenoid- and PHB-free double gene knockout strain mutant was constructed to simplify the purification steps normally involved in gellan production. However, the production of gellan gum was unexpectedly reduced. A mutant with 14.4% higher gellan production than that of the wild-type strain was obtained and isolated after employing UV and EMS combined mutagenesis. Based on this high-yield and low-impurity-producing mutant, a new recovery method requiring less organic solvent and fewer operating steps was developed. This method will effectively reduce the production costs and improve the economic benefits of large-scale gellan production.
Topics: Carotenoids; Ethyl Methanesulfonate; Fermentation; Gene Knockout Techniques; Hydroxybutyrates; Industrial Microbiology; Mutation; Polyesters; Polysaccharides, Bacterial; Sphingomonas; Ultraviolet Rays
PubMed: 31619503
DOI: 10.1128/mSphere.00668-19 -
Journal of Pharmaceutical Analysis Aug 2022Covalent organic nanospheres (CONs) were explored as a fiber coating for solid-phase microextraction of genotoxic impurities (GTIs) from active ingredients (AIs). CONs...
Covalent organic nanospheres (CONs) were explored as a fiber coating for solid-phase microextraction of genotoxic impurities (GTIs) from active ingredients (AIs). CONs were synthesized by an easy solution-phase procedure at 25 °C. The obtained nanospheres exhibited a high specific surface area, good thermostability, high acid and alkali resistance, and favorable crystallinity and porosity. Two types of GTIs, alkyl halides (1-iodooctane, 1-chlorobenzene, 1-bromododecane, 1,2-dichlorobenzene, 1-bromooctane, 1-chlorohexane, and 1,8-dibromooctane) and sulfonate esters (methyl -toluenesulfonate and ethyl -toluenesulfonate), were chosen as target molecules for assessing the performance of the coating. The prepared coating achieved high enhancement factors (5097-9799) for the selected GTIs. The strong affinity between CONs and GTIs was tentatively attributed to π-π and hydrophobicity interactions, large surface area of the CONs, and size-matching of the materials. Combined with gas chromatography-mass spectrometry (GC-MS), the established analytical method detected the GTIs in capecitabine and imatinib mesylate samples over a wide linear range (0.2-200 ng/g) with a low detection limit (0.04-2.0 ng/g), satisfactory recovery (80.03%-109.5%), and high repeatability (6.20%-14.8%) and reproducibility (6.20%-14.1%). Therefore, the CON-coated fibers are promising alternatives for the sensitive detection of GTIs in AI samples.
PubMed: 36105168
DOI: 10.1016/j.jpha.2021.12.002 -
Biotechnology Progress Jul 2021Cell culture medium (CCM) composition affects cell growth and critical quality attributes (CQAs) of monoclonal antibodies (mAbs) and recombinant proteins. One essential...
Cell culture medium (CCM) composition affects cell growth and critical quality attributes (CQAs) of monoclonal antibodies (mAbs) and recombinant proteins. One essential compound needed within the medium is iron because of its central role in many cellular processes. However, iron is also participating in Fenton chemistry leading to the formation of reactive oxygen species (ROS) causing cellular damage. Therefore, this study sought to investigate the impact of iron in CCM on Chinese hamster ovary (CHO) cell line performance, and CQAs of different recombinant proteins. Addition of either ferric ammonium citrate (FAC) or ferric citrate (FC) into CCM revealed major differences within cell line performance and glycosylation pattern, whereby ammonium was not involved in the observed differences. Inductively coupled plasma mass spectrometry (ICP-MS) analysis identified varying levels of impurities present within these iron sources, and manganese impurity rather than iron was proven to be the root cause for increased cell growth, titer, and prolonged viability, as well as altered glycosylation levels. Contrary effects on cell performance and protein glycosylation were observed for manganese and iron. The use of low impurity iron raw material is therefore crucial to control the effect of iron and manganese independently and to support and guarantee consistent and reproducible cell culture processes.
Topics: Animals; CHO Cells; Cricetinae; Cricetulus; Culture Media; Iron; Recombinant Proteins
PubMed: 33742789
DOI: 10.1002/btpr.3148 -
Molecules (Basel, Switzerland) Oct 2023This critical review points out the most serious and problematic issues to be found in the literature on the adsorption of dyes on clay minerals. The introduction draws... (Review)
Review
This critical review points out the most serious and problematic issues to be found in the literature on the adsorption of dyes on clay minerals. The introduction draws attention to the fundamental problems, namely the insufficient characterization of adsorbents, the influence of impurities on the adsorption of dyes, and the choice of inappropriate models for the description of the very complex systems that clay minerals and their systems represent. This paper discusses the main processes accompanying adsorption in colloidal systems of clay minerals. The relationship between the stability of the colloidal systems and the adsorption of dye molecules is analyzed. The usual methodological procedures for determining and evaluating the adsorption of dyes are critically reviewed. A brief overview and examples of modified clay minerals and complex systems for the adsorption of organic dyes are summarized. This review is a guide for avoiding some faults in characterizing the adsorption of organic dyes on clay minerals, to improve the procedure for determining adsorption, to evaluate results correctly, and to find an appropriate theoretical interpretation. The main message of this article is a critical analysis of the current state of the research in this field, but at the same time, it is a guide on how to avoid the most common problems and mistakes.
PubMed: 37836793
DOI: 10.3390/molecules28196951 -
RSC Advances Feb 2020Analysis of impurities is an important step in the quality control of pharmaceutical ingredients and final products. From drug synthesis or excipients, even in small...
Analysis of impurities is an important step in the quality control of pharmaceutical ingredients and final products. From drug synthesis or excipients, even in small concentrations, impurities may affect efficacy and safety. The method was developed following Quality by Design (QbD) for the analysis of the antidiabetic empagliflozin. The concept of QbD is used as a tool for the development of methods and formulations. Through predefined objectives and risk analysis, robust methodologies and reduced solvent consumption are developed. A simple HPLC method was developed and validated for the quantitative determination of empagliflozin and its organic impurities from the synthesis process. The method was carried out in a Shim-pack phenyl column with a mobile phase consisting of an acetonitrile/water mixture (72 : 28), with isocratic elution and the detector wavelength was 230 nm. The validation process, in accordance with international guidelines, shows that the method was linear, precise and accurate for empagliflozin, impurity 1 and impurity 2. Limits of detection (0.01, 0.02 and 0.01 μg mL) and quantification (0.10, 0.10 and 0.05 μg mL) were determined for EMPA, IMP1 and IMP2, respectively. The HPLC method for impurity determination in empagliflozin was linear, precise, accurate and robust. It can be successfully applied in the quality control of empagliflozin and the synthesis of impurities, being adequate for routine analysis.
PubMed: 35493885
DOI: 10.1039/c9ra08442h -
Membranes Dec 2020Membrane technology is a simple and energy-conservative separation option that is considered to be a green alternative for CO capture processes. However, commercially...
Membrane technology is a simple and energy-conservative separation option that is considered to be a green alternative for CO capture processes. However, commercially available membranes still face challenges regarding water and chemical resistance. In this study, the effect of water and organic contaminants in the feed stream on the CO/CH separation performance is evaluated as a function of the hydrophilic and permselective features of the top layer of the membrane. The membranes were a commercial hydrophobic membrane with a polydimethylsiloxane (PDMS) top layer (Sulzer Chemtech) and a hydrophilic flat composite membrane with a hydrophilic [emim][ac] ionic liquid-chitosan (IL-CS) thin layer on a commercial polyethersulfone (PES) support developed in our laboratory. Both membranes were immersed in NaOH 1M solutions and washed thoroughly before characterization. The CO permeance was similar for both NaOH-treated membranes in the whole range of feed concentration (up to 250 GPU). The presence of water vapor and organic impurities of the feed gas largely affects the gas permeance through the hydrophobic PDMS membrane, while the behavior of the hydrophilic IL-CS/PES membranes is scarcely affected. The effects of the interaction of the contaminants in the membrane selective layer are being further evaluated.
PubMed: 33302433
DOI: 10.3390/membranes10120405 -
Sensors (Basel, Switzerland) Nov 2022When developing methods for diagnosing pathologies and diseases in humans and animals using electronic noses, one of the important trends is the miniaturization of...
When developing methods for diagnosing pathologies and diseases in humans and animals using electronic noses, one of the important trends is the miniaturization of devices, while maintaining significant information for diagnostic purposes. A combination of several sorbents that have unique sorption features of volatile organic compounds (VOCs) on one transducer is a possible option for the miniaturization of sensors for gas analysis. This paper considers the principles of creating polycomposite coatings on the electrodes of piezoelectric quartz resonators, including the choice of sorbents for the formation of sensitive layers, determining the mass and geometry of the formation of sensitive layers in a polycomposite coating, as well as an algorithm for processing the output data of sensors to obtain maximum information about the qualitative and quantitative composition of the gas phase. A comparative analysis of the efficiency and kinetics of VOC vapor sorption by sensors with polycomposite coatings and a set of sensors with relevant single coatings has been carried out. Regression equations have been obtained to predict the molar-specific sensitivity of the microbalance of VOC vapors by a sensor with a polycomposite coating of three sorbents with an error of 5-15% based on the results of the microbalance of VOC vapors on single coatings. A method for creating "visual prints" of sensor signals with polycomposite coatings is shown, with results comparable to those from an array of sensors. The parameters A are proposed for obtaining information on the qualitative composition of the gas phase when processing the output data of sensors with polycomposite coatings. A biochemical study of exhaled breath condensate (EBC) samples, a microbiological investigation of calf tracheal washes, and a clinical examination were conducted to assess the presence of bovine respiratory disease (BRD). An analysis of the gas phase over EBC samples with an array of sensors with polycomposite coatings was also carried out. The "visual prints" of the responses of sensors with polycomposite coatings and the results of the identification of VOCs in the gas phase over EBC samples were compared to the results of bacteriological studies of tracheal washes of the studied calves. A connection was found between the parameters A of a group of sensors with polycomposite coatings and the biochemical parameters of biosamples. The adequacy of replacing an array of piezoelectric sensors with single coatings by the sensors with polycomposite coatings is shown.
Topics: Humans; Cattle; Animals; Volatile Organic Compounds; Electronic Nose; Gases; Quartz; Electrodes
PubMed: 36366226
DOI: 10.3390/s22218529