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Proteomes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 3
Author(s):  
Benjamin C. Orsburn ◽  
Sierra D. Miller ◽  
Conor J. Jenkins

Multiplexed proteomics using isobaric tagging allows for simultaneously comparing the proteomes of multiple samples. In this technique, digested peptides from each sample are labeled with a chemical tag prior to pooling sample for LC-MS/MS with nanoflow chromatography (NanoLC). The isobaric nature of the tag prevents deconvolution of samples until fragmentation liberates the isotopically labeled reporter ions. To ensure efficient peptide labeling, large concentrations of labeling reagents are included in the reagent kits to allow scientists to use high ratios of chemical label per peptide. The increasing speed and sensitivity of mass spectrometers has reduced the peptide concentration required for analysis, leading to most of the label or labeled sample to be discarded. In conjunction, improvements in the speed of sample loading, reliable pump pressure, and stable gradient construction of analytical flow HPLCs has continued to improve the sample delivery process to the mass spectrometer. In this study we describe a method for performing multiplexed proteomics without the use of NanoLC by using offline fractionation of labeled peptides followed by rapid “standard flow” HPLC gradient LC-MS/MS. Standard Flow Multiplexed Proteomics (SFloMPro) enables high coverage quantitative proteomics of up to 16 mammalian samples in about 24 h. In this study, we compare NanoLC and SFloMPro analysis of fractionated samples. Our results demonstrate that comparable data is obtained by injecting 20 µg of labeled peptides per fraction with SFloMPro, compared to 1 µg per fraction with NanoLC. We conclude that, for experiments where protein concentration is not strictly limited, SFloMPro is a competitive approach to traditional NanoLC workflows with improved up-time, reliability and at a lower relative cost per sample.


2022 ◽  
Vol 51 (4) ◽  
pp. 723-732
Author(s):  
Lev Oganesyants ◽  
Elena Sevostianova ◽  
Elena Kuzmina ◽  
Mikhail Ganin ◽  
Eugene Chebykin ◽  
...  

Introduction. Due to its natural composition, the deep water of Lake Baikal can be bottled without any conserving agents. The development of large-scale production of bottled Baikal water requires its detailed study in order to protect it from counterfeit and falsification. The purpose of this work was to study the isotopic and chemical composition of the deep water of Lake Baikal and offer indicators for its identification. Study objects and methods. The research included deep water of Lake Baikal, sampled at various points, the water from the Angara River, and the tap water from the cities of Irkutsk and Shelekhov. The tests were performed using a quadrupole ICP-MS mass spectrometer and a Delta V Plus isotope mass spectrometer with a GasBench II module. Results and discussion. All the water samples revealed fresh water with insignificant mineralization. As for salts, the deep water samples had a lower content of sodium and chlorides, as well as a higher content of silicon. As for metals, the deep water samples contained iron, manganese, copper, and zinc; in the tap water samples, these indicators were significantly higher. Unlike that of the Angara water samples, the isotopic profile of the deep water samples was somewhat “lighter”, both in the ratio of oxygen isotopes δ18O – by 0.73‰, and hydrogen δD – by 0.49‰. The tap water samples had a higher deuterium content. The content of oxygen isotopes (δ18O) in the tap water samples was close to that in the Angara samples. Conclusion. The complex physicochemical and isotope analyses expanded the list of identification indicators and made it possible to identify the deep water of Lake Baikal.


Author(s):  
Christian Siemes ◽  
Stephen Maddox ◽  
Olivier Carraz ◽  
Trevor Cross ◽  
Steven George ◽  
...  

AbstractCold Atom technology has undergone rapid development in recent years and has been demonstrated in space in the form of cold atom scientific experiments and technology demonstrators, but has so far not been used as the fundamental sensor technology in a science mission. The European Space Agency therefore funded a 7-month project to define the CASPA-ADM mission concept, which serves to demonstrate cold-atom interferometer (CAI) accelerometer technology in space. To make the mission concept useful beyond the technology demonstration, it aims at providing observations of thermosphere mass density in the altitude region of 300–400 km, which is presently not well covered with observations by other missions. The goal for the accuracy of the thermosphere density observations is 1% of the signal, which will enable the study of gas–surface interactions as well as the observation of atmospheric waves. To reach this accuracy, the CAI accelerometer is complemented with a neutral mass spectrometer, ram wind sensor, and a star sensor. The neutral mass spectrometer data is considered valuable on its own since the last measurements of atmospheric composition and temperature in the targeted altitude range date back to 1980s. A multi-frequency GNSS receiver provides not only precise positions, but also thermosphere density observations with a lower resolution along the orbit, which can be used to validate the CAI accelerometer measurements. In this paper, we provide an overview of the mission concept and its objectives, the orbit selection, and derive first requirements for the scientific payload.


2022 ◽  
Author(s):  
Subasri Mani ◽  
Gomathi Veu ◽  
Kavitha Mary Jackson

Abstract The present study was aimed to explore the characterization of polyhydroxy butrate extracted from the bacterial strain under optimized conditions for the production of bioplastic. Under optimized fermentation conditions, Polyhydroxy butrate (PHB) was extracted and subjected to examine their properties via Thin Layer Chromotogram (TLC), Gas Chromotogram- Mass Spectrometer (GC-MS), Fourier Transform Infrared spectrum (FTIR). The presence of a brown spot in the TLC plate indicates the presence of hydroxylgroup which is similar to the polymer group. GC-MS analysis of extracted PHB shows peaks at the retention time of 3.8, 11.6 which is corresponding to octadecanoic acid, hexadecanoic acid, butyl -2-ethylester confirms the presence of polymeric nature in the extracted PHB. The absorption bands of FTIR at 1719–1720 cm −1 indicate the presence of C=O group of PHB. The absorption peaks at wave numbers 500-1000 cm -1 , 1055 cm -1 and 1230 cm -1 denotes (OH) group, (C–O) stretch and (C=O) ester group. From these results, it was confirmed that the extracted PHB is having the potential to replace petroleum plastic.


Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 86
Author(s):  
Luyang Jiao ◽  
Mengying Du ◽  
Yameng Hou ◽  
Yuan Ma ◽  
Xianglei Kong

The strong chiral preferences of some magic clusters of amino acids have attracted continually increasing interests due to their unique structures, properties and possible roles in homochirogenesis. However, how chirality can influence the generation and stability of cluster ions in a wild range of cluster sizes is still unknown for most amino acids. In this study, the preference for threonine clusters to form homochiral and heterochiral complex ions has been investigated by electrospray ionization (ESI) mass spectrometry. Abundant cluster [Thrn+mH]m+ ions (7 ≤ n ≤ 78, 1 ≤ m ≤ 5) have been observed for both samples of enantiopure (100% L) and racemic (50:50 L:D) threonine solutions. Further analyses of the spectra show that the [Thr14+2H]2+ ion is characterized by its most outstanding homochiral preference, and [Thr7+H]+ and [Thr8+H]+ ions also clearly exhibit their homochiral preferences. Although most of the triply charged clusters (20 ≤ n ≤ 36) are characterized by heterochiral preferences, the quadruply charged [Thrn+4H]4+ ions (40 ≤ n ≤ 59) have no obvious chiral preference in general. On the other hand, a weak homochiral preference exists for most of the quintuply charged ions observed in the experiment.


2022 ◽  
Author(s):  
Siman Ren ◽  
Lei Yao ◽  
Yuwei Wang ◽  
Gan Yang ◽  
Yiliang Liu ◽  
...  

Abstract. The volatility of organic aerosols plays a key role in determining their gas-particle partitioning, which subsequently alters the physicochemical properties and atmospheric fates of aerosol particles. Nevertheless, an accurate estimation of the volatility of organic aerosols (OA) remains challenging. Because most standard particulate organic compounds are scarce, on the other hand, their vapor pressures are too low to estimate by most traditional methods. Here, we deployed an iodide-adduct Long Time-of-Flight Chemical Ionization Mass Spectrometer (LToF-CIMS) coupled with a Filter Inlet for Gases and AEROsols (FIGAERO) to probe the relationship between the molecular formulas of atmospheric organic aerosol’s components and their volatilities. A number of Tmax (i.e., the temperature corresponding to the first signal peak of thermogram) were abstracted and validated from the desorption thermograms of mixed organic and inorganic calibrants which were atomized and then collected onto a Teflon filter. Besides, 30 filter samples of ambient air were collected in winter 2019 at Wangdu station in Beijing-Tianjin-Hebei region, and analyzed by FIGAERO-LToF-CIMS, leading to the identification of 1,448 compounds dominated by the CHO (containing carbon, hydrogen, and oxygen atoms) and CHON (containing carbon, hydrogen, oxygen, and nitrogen atoms) species. Among them, 181 organic formulas including 91 CHO and 90 CHON compounds were then selected since their thermograms can be characterized with clear Tmax values in more than 20 out of 30 filter samples and subsequently divided into two groups according to their O / C ratios. The mean O / C of these two groups are 0.56 ± 0.35 (average ± one standard deviation) and 0.18 ± 0.08, respectively. We then obtained the correlation functions between volatility and elemental composition for the two group compounds. Compared with previous volatility parameterizations, our correlation functions provide a better estimation of the volatility of semi-volatility organic compounds (SVOCs) and low-volatility organic compounds (LVOCs) in the ambient organic aerosols. Furthermore, we suggest that there should be specialized volatility parameterizations for different O / C organic compounds.


2022 ◽  
Vol 15 (1) ◽  
pp. 11-19
Author(s):  
Dina Alfaouri ◽  
Monica Passananti ◽  
Tommaso Zanca ◽  
Lauri Ahonen ◽  
Juha Kangasluoma ◽  
...  

Abstract. Sulfuric acid and dimethylamine vapours in the atmosphere can form molecular clusters, which participate in new particle formation events. In this work, we have produced, measured, and identified clusters of sulfuric acid and dimethylamine using an electrospray ionizer coupled with a planar-differential mobility analyser, connected to an atmospheric pressure interface time-of-flight mass spectrometer (ESI–DMA–APi-TOF MS). This set-up is suitable for evaluating the extent of fragmentation of the charged clusters inside the instrument. We evaluated the fragmentation of 11 negatively charged clusters both experimentally and using a statistical model based on quantum chemical data. The results allowed us to quantify the fragmentation of the studied clusters and to reconstruct the mass spectrum by removing the artifacts due to the fragmentation.


2022 ◽  
Vol 17 (01) ◽  
pp. C01031
Author(s):  
C. Vogl ◽  
M. Schwarz ◽  
X. Stribl ◽  
J. Grießing ◽  
P. Krause ◽  
...  

Abstract Liquid argon (LAr) is a common choice as detection medium in particle physics and rare-event searches. Challenges of LAr scintillation light detection include its short emission wavelength, long scintillation time and short attenuation length. The addition of small amounts of xenon to LAr is known to improve the scintillation and optical properties. We present a characterization campaign on xenon-doped liquid argon (XeDLAr) with target xenon concentrations ranging from 0 to 300 ppm by mass encompassing the measurement of the photoelectron yield Y, effective triplet lifetime τ 3 and effective attenuation length λ att. The measurements were conducted in the Subterranean Cryogenic ARgon Facility, Scarf, a 1 t (XeD)LAr test stand in the shallow underground laboratory (UGL) of TU-Munich. These three scintillation and optical parameters were observed simultaneously with a single setup, the Legend Liquid Argon Monitoring Apparatus, Llama. The actual xenon concentrations in the liquid and gaseous phases were determined with the Impurity DEtector For Investigation of Xenon, Idefix, a mass spectrometer setup, and successful doping was confirmed. At the highest dopant concentration we find a doubling of Y, a tenfold reduction of τ 3 to ∼90 ns and a tenfold increase of λ att to over 6 m.


Author(s):  
Yi-Hsin Chen ◽  
Chia-Yu Liu ◽  
Zachary J. Devereaux ◽  
Chia-Yun Wang ◽  
Sarah Trimpin ◽  
...  

2022 ◽  
Vol 34 (2) ◽  
pp. 429-431
Author(s):  
A.I. Kozhushkevich ◽  
E.S. Kozeicheva ◽  
A.M. Lebedev ◽  
V.V. Ovcharenko ◽  
A.M. Kalantaenko

Due to the increasing globalization of food markets, there are evolving new challenges for maintaing food safety. The current problem is the development of analytical methods for 3-monochloropropanediol ester and glycidol ester, which are food contaminants of concern for the scientific community. The levels of 3-monochloropropanediol ester and glycidol ester in certain food products are controlled by the European legislation. However, the maximum allowed concentrations and uptake limits for various food products are permanently revised. Therefore, we aimed to determine 3-monochloropropanediol ester and glycidol ester in various food products, which may contain vegetable oils. We analyzed food samples obtained from local food shops, predominantly low-priced products, which are more likely to contain vegetable oils, and adulterated milk fat. The levels of 3-monochloropropanediol ester and glycidol ester were determined indirectly by analyzing free 3-monochloropropanediol and glycidol ester obtained by hydrolysis and derivatized with phenylboronic acid. Samples were analyzed by GC-MS/MS on a triple-quad mass spectrometer.


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