scholarly journals What have we known so far for fluorescence staining and quantification of microplastics: A tutorial review

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shengdong Liu ◽  
Enxiang Shang ◽  
Jingnan Liu ◽  
Yining Wang ◽  
Nanthi Bolan ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Compositional Analysis ◽  
Optimal Operation ◽  
Spectroscopic Techniques ◽  
Sample Collection ◽  
Fluorescence Staining ◽  
Heating And Cooling ◽  
Staining Methods ◽  
The Stability ◽  
Digestion Step

AbstractUnderstanding the fate and toxicity of microplastics (MPs, < 5 mm plastic particles) is limited by quantification methods. This paper summarizes the methods in use and presents new ones. First, sampling and pretreatment processes of MPs, including sample collection, digestion, density separation, and quality control are reviewed. Then the promising and convenient staining procedures and quantification methods for MPs using fluorescence dyes are reviewed. The factors that influence the staining of MPs, including their physicochemical properties, are summarized to provide an optimal operation procedure. In general, the digestion step is crucial to eliminate natural organic matter (NOM) to avoid interference in quantification. Chloroform was reported to be the most appropriate solvent, and 10–20 μg/mL are recommended as optimal dye concentrations. In addition, a heating and cooling procedure is recommended to maintain the fluorescence intensity of MPs for two months. After staining, a fluorescence microscope is usually used to characterize the morphology, mass, or number of MPs, but compositional analysis cannot be determined with it. These fluorescence staining methods have been implemented to study MP abundance, transport, and toxicity and have been combined with other chemical characterization techniques, such as Fourier transform infrared spectroscopy and Raman spectroscopy. More studies are needed to focus on the synthesis of novel dyes to avoid NOM’s interference. They need to be combined with other spectroscopic techniques to characterize plastic composition and to develop image-analysis methods. The stability of stained MPs needs to be improved.

Optimization of the time the chromatograph thermostats exit to a given temperature

2020 ◽  
pp. 40-45
Author(s):  
Nadezhda O. Vzduleva ◽  
Valery B. Gitlin
Keyword(s):  
Heating Rate ◽  
Entire Range ◽  
Gas Chromatograph ◽  
Heating And Cooling ◽  
Operating Temperatures ◽  
The Stability

The problems of ensuring the stability of the temperature of the chromatographic experiment carried out using a serial gas chromatograph LGH-3000 are considered. Limiting the permissible heating rate of the chromatograph thermostats does not allow a quick transition to the new conditions of the chromatographic experiment in accordance with the requirements of the technical conditions. The processes of heating and cooling the thermostat are analyzed. It is shown that the ratio of the duration of the interval equal to the sum of the durations of the heating and cooling intervals to the duration of the heating interval is inversely proportional to the temperature of the chromatographic experiment. Based on this situation, an empirical algorithm is proposed for heating the thermostat to a given temperature, which made it possible to reduce the time it takes to reach a given temperature in the entire range of operating temperatures.

scholarly journals 3D sub-nanometer analysis of glucose in an aqueous solution by cryo-atom probe tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. M. Schwarz ◽  
C. A. Dietrich ◽  
J. Ott ◽  
E. M. Weikum ◽  
R. Lawitzki ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Density Functional ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Characterization Methods ◽  
Signal Deconvolution ◽  
The Stability ◽  
Frozen Solutions ◽  
3D Volume

AbstractAtom Probe Tomography (APT) is currently a well-established technique to analyse the composition of solid materials including metals, semiconductors and ceramics with up to near-atomic resolution. Using an aqueous glucose solution, we now extended the technique to frozen solutions. While the mass signals of the common glucose fragments CxHy and CxOyHz overlap with (H2O)nH from water, we achieved stoichiometrically correct values via signal deconvolution. Density functional theory (DFT) calculations were performed to investigate the stability of the detected pyranose fragments. This paper demonstrates APT’s capabilities to achieve sub-nanometre resolution in tracing whole glucose molecules in a frozen solution by using cryogenic workflows. We use a solution of defined concentration to investigate the chemical resolution capabilities as a step toward the measurement of biological molecules. Due to the evaporation of nearly intact glucose molecules, their position within the measured 3D volume of the solution can be determined with sub-nanometre resolution. Our analyses take analytical techniques to a new level, since chemical characterization methods for cryogenically-frozen solutions or biological materials are limited.

THE DEVELOPMENT OF A METHOD FOR DIRECT MASS SPECTROMETRIC ANALYSIS OF BIOLOGICAL SAMPLES USING POROUS SAMPLERS

2021 ◽  
Vol 55 (1) ◽  
pp. 99-103
Author(s):  
R.E. Levin ◽  
◽  
M.A. Shamraeva ◽  
I.M. Larina ◽  
D.S. Bormotov ◽  
...  
Keyword(s):  
Biological Samples ◽  
Biological Fluids ◽  
Storage Conditions ◽  
Spectrometric Analysis ◽  
Sample Collection ◽  
Mucous Membranes ◽  
The Status ◽  
Direct Mass Spectrometry ◽  
The Stability ◽  
Blood Spot

The paper presents a method for rapid multi-omics investigation of biological samples using polypropylene bulk porous samplers. The use of porous samplers makes it easy to collect samples from the surface of the skin, mucous membranes, and biological fluids even in a field, and the surfaces of wounds and injuries. Collected samples do not require special storage conditions, and the samplers are lightweight and very compact. They can be used to monitor the condition of cosmonauts before, during, and after the spaceflight with the same sample collection method. The analysis of biomaterial applied to the sampler is performed using direct mass spectrometry methods, similar to the dried blood spot technique that is already used in clinical practice. However, bulk porous samplers allow expanding the range of analytes ionization conditions, which increases the stability and reliability of the ionization process, which expands the variety of analyzed molecules. The proposed method can be used to study compounds of various classes, including proteins, lipids, and metabolites, to systematically monitor the status of people in extreme conditions (athletes, astronauts), or to study the condition of patients in the clinic.

scholarly journals Synthesis of Some 3d Metal Complexes of Quinine and their Toxicological Studies

1970 ◽  
Vol 25 ◽  
pp. 19-28 ◽  
Author(s):  
Adedibu C. Tella ◽  
Joshua A. Obaleya
Keyword(s):  
Stability Constant ◽  
Metal Complexes ◽  
Chemical Society ◽  
Cinchona Alkaloids ◽  
Albino Rats ◽  
Spectroscopic Techniques ◽  
Tetrahedral Geometry ◽  
Toxicological Studies ◽  
3D Metal Complexes ◽  
The Stability

Four metal complexes of antimalarials cinchona alkaloids; [Co(Quin)Cl3]-1,[Fe(Quin)Cl2H2O]SO3H2O-2, [Cu(Quin)ClSO4]∞-3 and [Cd(Quin)ClSO4]∞-4 have beensynthesized and characterized by elemental analysis, conductivity, magnetic moment, IR,UV-Vis and mass spectroscopic techniques. The tetrahedral geometry is assigned for all thefour complexes and the quinine ligand is protonated at quinuclidine N atom with thecoordination of the metal at quinoline N atom for all the complexes. Complexes 1 and 2have zwitterionic structures while complexes 3 and 4 are polymeric in nature with zig-zagextended chains (MCl- O -SO2- O -MCl- O –SO2---).Stability constant of the complexes were evaluated for the metal salts. The value of thestability constant (β) was found to be log 10.48, 9.92, 7.98 and 7.81 for Cu(II), Fe(III),Co(II) and Cd(II), respectively and the order of β was found to beCu(II)>Fe(III)>Co(II)>Cd(II). The stability constant data revealed that concomitantlyadministration of quinine with preparation containing these metals may reduce theirefficacy. Toxicological study was carried out by investigating the effect of administration ofthe complexes on alkaline phosphatase activity of kidney, liver and serum of Albino rats. Allthe examined four metal complexes were found to be non-toxic.Keywords: Quinine, stability constant, FTIR, MS, phosphates activity.DOI:  10.3126/jncs.v25i0.3280Journal of Nepal Chemical Society Volume 25, 2010 pp 19-28

scholarly journals Evaluation of Anti-biofilm Potential of Biosurfactant Extracted from Nocardia Species

Folia Medica ◽  
2021 ◽  
Vol 63 (3) ◽  
pp. 392-399
Author(s):  
Ali Javadi ◽  
Mohamad Reza Pourmand ◽  
Javad Hamedi ◽  
Fatemeh Gharebaghi ◽  
Zohre Baseri ◽  
...  
Keyword(s):  
Agar Plate ◽  
Compositional Analysis ◽  
16S Rrna Gene Sequencing ◽  
Hydrocarbon Chain ◽  
Laboratory Method ◽  
Rrna Gene ◽  
Surface Active Agents ◽  
Rrna Gene Sequencing ◽  
The Stability ◽  
Spreading Test

Introduction: Bacterial natural products such as biosurfactants and surface-active agents are important compounds which exhibit many applications in the &#64257;elds of medicine.Aim: The aim of the present study was to isolate and identify Nocardia strains with high biosurfactant production and antibiofilm ability.Materials and methods: In the present study, a biosurfactant producing Nocardia species was isolated and identi&#64257;ed by a laboratory method. Nocardia species were initially screened and then tested for their ability to produce biosurfactant. The oil spreading test and the surface tension measurements showed that one strain was a biosurfactant producer. The strain with the best surface activity results was selected for further studies and identified by 16S rRNA gene sequencing method. Fourier transform infrared spectroscopy (FTIR) and compositional analysis proved a biosurfactant structure.Results: Oil spreading test and blue agar plate test confirmed biosurfactants and extracellular anionic glycolipids. E24% assay using olive oil revealed strong emulsifying characteristic of the extracted biosurfactant with 100% emulsifying strength. FTIR spectrum indicated the presence of aliphatic hydrocarbon chain (lipid) along with the polysaccharide portion, confirming the glycolipid nature of the biosurfactant. The stability of the biosurfactant produced in different conditions was significant. Increasing concentration of BS significantly inhibited Pseudomonas aeruginosa biofilm.Conclusions: N. coubleae can be a representative of the genus Nocardia for the production of biosurfactants with beneficial physicochemical properties.

scholarly journals Inactivation of SARS-CoV-2 virus in saliva using a guanidium based transport medium suitable for RT-PCR diagnostic assays

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252687
Author(s):  
Sukalyani Banik ◽  
Kaheerman Saibire ◽  
Shraddha Suryavanshi ◽  
Glenn Johns ◽  
Soumitesh Chakravorty ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Viral Rna ◽  
Clinical Samples ◽  
Sample Collection ◽  
Rt Pcr ◽  
Diagnostic Assays ◽  
Guanidinium Thiocyanate ◽  
Upper Respiratory ◽  
Polymerase Chain ◽  
The Stability

Background Upper respiratory samples used to test for SARS-CoV-2 virus may be infectious and present a hazard during transport and testing. A buffer with the ability to inactivate SARS-CoV-2 at the time of sample collection could simplify and expand testing for COVID-19 to non-conventional settings. Methods We evaluated a guanidium thiocyanate-based buffer, eNAT™ (Copan) as a possible transport and inactivation medium for downstream Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) testing to detect SARS-CoV-2. Inactivation of SARS-CoV-2 USA-WA1/2020 in eNAT and in diluted saliva was studied at different incubation times. The stability of viral RNA in eNAT was also evaluated for up to 7 days at room temperature (28°C), refrigerated conditions (4°C) and at 35°C. Results SARS-COV-2 virus spiked directly in eNAT could be inactivated at >5.6 log10 PFU/ml within a minute of incubation. When saliva was diluted 1:1 in eNAT, no cytopathic effect (CPE) on VeroE6 cells was observed, although SARS-CoV-2 RNA could be detected even after 30 min incubation and after two cell culture passages. A 1:2 (saliva:eNAT) dilution abrogated both CPE and detectable viral RNA after as little as 5 min incubation in eNAT. SARS-CoV-2 RNA from virus spiked at 5X the limit of detection remained positive up to 7 days of incubation in all tested conditions. Conclusion eNAT and similar guanidinium thiocyanate-based media may be of value for transport, stabilization, and processing of clinical samples for RT-PCR based SARS-CoV-2 detection.

The Influence of Heating and Cooling on the Stability of a Liquid Layer

1980 ◽  
Vol 23 (176) ◽  
pp. 224-230 ◽  
Author(s):  
Yasuo IWASAKI ◽  
Eiji HASEGAWA
Keyword(s):  
Liquid Layer ◽  
Heating And Cooling ◽  
The Stability

scholarly journals Etazene (N,N-diethyl-2-{[(4-ethoxyphenyl)methyl]-1H-benzimidazol-1-yl}-ethan-1-amine (dihydrochloride)): a novel benzimidazole opioid NPS identified in seized material: crystal structure and spectroscopic characterization

2020 ◽  
Author(s):  
Marta Siczek ◽  
Marcin Zawadzki ◽  
Miłosz Siczek ◽  
Agnieszka Chłopaś-Konowałek ◽  
Paweł Szpot
Keyword(s):  
Crystal Structure ◽  
Analytical Data ◽  
Chemical Characterization ◽  
Drug Market ◽  
Spectroscopic Characterization ◽  
Illegal Drug ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Full Characterization

Abstract Purpose The aim of the study was to present the spectroscopic characteristics and crystal structure of the etazene—a benzimidazole opioid, which appeared on the illegal drug market in Poland in the last weeks. Methods The title compound was analyzed by X-ray crystallography as well as gas and liquid chromatography combined with mass spectrometry. Spectroscopic techniques have also been used, such as nuclear magnetic resonance, infrared and ultraviolet-visible spectroscopies. Results We presented the identification and the broad chemical characterization of etazene, a synthetic opioid that has recently been introduced on the illegal drug market. Conclusions In this paper, we described single-crystal X-ray, chromatographic and spectroscopic characterization of a synthetic opioid that emerged on the new psychoactive substance (NPS) market in Poland. To the best of our knowledge, this is the first full characterization of etazene. Analytical data presented in the work can be helpful in identification and detection of the NPS in forensic and clinical laboratories.

Short-term stability of free metanephrines in plasma and whole blood

2020 ◽  
Vol 58 (5) ◽  
pp. 753-757 ◽  
Author(s):  
Elisa Danese ◽  
Martina Montagnana ◽  
Claudio Brentegani ◽  
Giuseppe Lippi
Keyword(s):  
Whole Blood ◽  
Repeated Measures ◽  
Sample Collection ◽  
Short Term ◽  
Total Change ◽  
Term Stability ◽  
Before And After ◽  
Liquid Chromatography Tandem Mass ◽  
The Mean ◽  
The Stability

AbstractBackgroundAnalysis of plasma metanephrine (MN) and normetanephrine (NMN) with liquid chromatography tandem mass spectrometry (LC-MS/MS) is the gold standard for the screening of pheochromocytomas and paragangliomas (PPGLs). As scarce information is available on the stability of MNs in diagnostic samples, this study was aimed at analyzing the short-term stability of plasma free MNs in whole blood and plasma, using LC-MS/MS.MethodsThe stability of plasma MNs was evaluated after sample collection at 1, 2 and 3 h in whole blood, and at 2, 4 and 6 h in centrifuged samples. Both studies were performed while maintaining the samples at room temperature (RT) and at 4 °C. The ClinMass Complete Kit (Recipe, Munchen, Germany) was used for measuring MNs with LC-MS/MS (Nexera X2 UHPLC-4500MD Sciex). Differences from the baseline (T0) were assessed using repeated measures one-way ANOVA, Students’ paired t-test and a comparison of the mean percentage changes with the total change limit (TCL).ResultsStatistically significant differences from T0 were found for both MNs (p < 0.001) in whole blood stored at RT, and for NMN (p = 0.028) but not MN (p = 0.220) at 4 °C. The mean difference exceeded the TCL after 1 h and 3 h at RT for MN, and after 1 h at RT for NMN. Statistically significant differences from T0 were only observed in the plasma samples for NMN at RT (p = 0.012), but the variation was within the TCL.ConclusionsMN and NMN displayed different patterns of stability before and after centrifugation. Even short-time storage at RT in whole blood should hence be avoided.

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