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Questions related to Chemical Analysis
I want to estimate freezing point of a mixture made from Ehhanol (H₃CCH₂OH, MW: 46.07 g/mol) , mono propylene glycol (CH₃CH(OH)CH₂OH, MW: 76.1 g/mol) and water. And the ratio of the mixure will vary for example I can start with 1:1:1 and so on. I spent couple of week to google it but not able to figure out how to do that. If someone here have some experience with it or have some suggestion / literature then please help to solve for this problem.
I am trying to obtain chitin by a chemical method. After deproteinization and demineralization processes, the powder obtained after each step is too alkaline or acidic respectively. Then, I spend a lot of deionized water during washing power. Is it acceptable to add something to the deionized water to get neutrality faster?
I know magnetic separation can separate Fe, γ-Fe2O3, Fe3O4. But I don't know how to get Fe powders from residues. Someone say sodium pyrophosphate could remove γ-Fe2O3, Fe3O4, is it a feasible method ? Or other better method?
Thanks very much for your answers!
Excessive use of chemicals in agriculture results in contamination of products with high levels of chemical residues.
Dear Researchers :
I have this question and I have an hypothesis:
Why Natural HDPE, when extruded at temperatures about 100 °C (around) it has a white (but pale white), and then when the polymer cools down it color turns between white an yellow.
I understand that this phenomenon it is a general case of all LLDPE, LDPE and HDPE , and in all fabrication processes : Extrusion, injection, molding, pressing, etc.
So this is fundamentally, a chemical characteristic of the material ...
It has to do with a change in the Oxygen concentration in the material ?
Thank you all in advance,
Best Regards !
I have been trying to detect a compound using a GC-MS system, but the probability is not high enough thanks to a lot of other compounds with similar mass spectra in NIST library. The only way I can think of to distinguish among them is retention index since some of those compounds are hard to obtain. I noticed that temperature programmed retention indices are not really system independent.
Therefore, under what conditions beside same stationary phases (DB-5MS in my case) can I make a comparison? Should the temperature programs and column lengths strictly match?
Thanks in advance for any advice.
Q1: In many articles on jadeite and jadeitite(Shi 2008,CÁRDENAS-PÁRRAGA2021, Meng 2016, Abduriyim2017, et al.), scholars draw spider diagram based on trace element data and REE from LA-CIP-MS. But the number of elements in the horizontal coordinate is often different. What is the principle on which this is selected?
Q2: When some of the results of the test are below the detection limit(bdl) , or the corresponding elements are not detected (nd), how should they be reflected in the diagram?
Hello all,
I am preparing a compilation file for doing MESMER calculations but I am having an issue. I am running some g08 calculations with acetyl and it seems like the transition state from for going to the RO2 to QOOH is unstable as the difference between the target energy and the calculated energy differs by about 0.1 - 1.1. There is too big a difference in the energy barriers between the RO2 and QOOH, but all other energies for the stationary points in the channels are comparative to the expected value. The IRC from the obtained transition state gave a significantly high "jump" in the potential energy graph. Would anyone happen to know what is going on?
What is the approximate COD value of 50 ppm aqueous Acetaminophen solution (C8H9NO2, Mol wt 151.163 g/mol)?
Nbc-Ni Cermets samples are sintered in a vacuum sintering furnace at @1450 degrees. The Samples were placed in the Alumina Piece as shown in the attached pictures. after sintering the color of the alumina piece changes to blue as shown in the picture. what can be the reason behind it? Thanks
I prepared a solution of 100ml THF, 20ml tert-butoxide in THF and 4ml 1,3-propane sultone. To this, I added 11gm of my nanoparticles. Once I receive the result of ICP-AES, how should I calculate the number of particles present? How should I check whether I have achieved proper functionalization of my sample or not?
I have sent 1gm of sample powder for analysis.
Any suggestions will be much appreciated.
Rare-earth halide/Rare-earth oxyhalide + alkali metal oxide = ?
For example, GdX3 + Li2O = ? at high temperature (~1300 C)
Please provide reference on your answer.
Thanks in advance
I was unable to perform the sampling and analysis for 40 surface water and 20 groundwater samples, so I hired an in-country consultant firm to do it. The results that they returned were difficult to interpret and had extremely high levels of iron and manganese. I spoke with a former professor and he expressed concern from his long career of working in SE Asia that the subcontractor/lab might not have filtered the samples. How can I know that the results are for the water and not the particulates?
I measured the particles size (<1000 nm) in aqueous solutions by DLS, but I found these particles can aggregate spontaneously, and it seems that smaller particles aggregate more.
I sincerely hope you can help me explain this phenomena.
We have now over 350 000 chemicals and mixtures of chemicals registered for production and use, and more are developed constantly. How can we speed up their assessment for safety, to erase the backlog of unexamined ones?
Hello, I have some doubts about DLS measuring the size of the nanoparticles.I hope to get answers from you.
I measure TiO2-NPs(60nm,commercialization ) in 0.01M PBS. But Instrument prompt “sample too polydisperse for cumulant analysis” and “sample too polydisperse for distribution analysis” .Correlation Functions show the picture as followed. Why does this happen and how to avoid it ?
All dispersions were filtered with 0.45um filter. Ultrasonic dispersionwas used.
Hi, could you recommend a software compatible with spectrophotometry from various brands?
P.S: I wash the column with water and methanol when I open and close the HPLC system.
I have modified the graphene surface with copper oxide nanoparticles. so, I need to know whether my modification is correct or not? so what kind of characterization technique do I need to follow? XRD, EDS, AFM, FTIR are accessible for me.
What are the benefits and the disadvantages of those?
what industries use those item beside Textile and paints?
does it have any other uses beside as dispersing agent?
which one gives more water resistance in paint and why?
Palmyrah fruit pulp has a bitter taste due to this saponin, so I have to remove the saponin with a cheaper method which can be applicable to the fruit industry.
Where can I find alagebrium I want to use it in my research ?
And astaxanthin also and is it expensive?
Try to do a research for making a physical or chemical reaction in CO2 to transform it to Carbon and Diamond. What is the possibility for that ?
Why the DNA sample that recovered from urea polyacrylamide gel electrophoresis become iced/solid during the ethanol preparation ?
I would like to analyse monocarboxylic acids higher than C20 (at least up to C30), but I cannot find a company for buying them. I prefer a mixture of more acids in an organic solvent but it can be solid standards. Thank you.
say, when we take a simple titration of any compound to induce some change and study the change what we can see the change if it is faster change in the optical parameter or change in absorption or energy change or when we do its electro chemical analysis the changed species will be faster response as its electron transfer, what will be faster ? or both the methodologies will be different in kinetics due to different technical aspects and parameters? optical corresponds to the technique spectrophotometric methods . and more elaboratively from which technique we can get better electron transfer kinetics or the accurate degree of minimal observable change.
Different results were obtained from both
Dear researchers,
I do not know how to use Origin software to draw a graph with very high (3000) and very low (100) numbers on the vertical axis. Could you please help me?
Dear all,
Would you please help me to find out the best approach to calculate the potential heat recovery from exothermic reactions? Are there any good references to introduce me in order to enhance my knowledge over recovering heat from exothermic reactions. I will be very thankful for your helpful advice and recommendations.
Thanks in Advance for your kind considerations.
Yours faithfully,
Nashmin
C1s peak at 284.8 corresponding to Adventitious Carbon is a reference for the X-ray photoelectron spectroscopy (XPS. However, when using carbon-based support, say Vulcan carbon (rich in graphitic carbon), r-GO and GO for deposition of active catalyst.
The C1s peak in these cases will be dominated by sp2 carbons, not by Adventitious Carbon.
How to calibrate the XPS data in that case?
How to account for the charging problem?
Thanks in advance
Hi, We want to measure the radiation patterns of an implantable antenna. The mimicking gel that we are using has different conductivity than that used for simulations. We want to increase the conductivity of our mimicking gel without increasing the permittivity.
We know that adding sugar and salt will increase the conductivity. However, it decreases the permittivity!!!
Any suggestions?
I am trying to analyse a certain material in a certain food product via HPLC. However, I crossed problems and tried to correct them but problem goes on.
After i see baseline in HPLC, i put standards and then my sample vial.
My sample showed a peak more area than standard peaks area. As first correction, i sent more concentration standard to HPLC column, Then i recognised that my sample peak got increase. As i increase standard concentration, peak of sample getting increase
As second application, i tried diluting sample concentration. Firstly i sent standards then i applied samples which are different concentration. But it didnt work well. For each diluted sample i read two times but machine didnt read peak of sample accurately. While first parallel showed a peak, second parallel didnt show any peak.
I cleaned HPLC column with mobile phase but it didnt change results. After cleaning of column i get a baseline but while reading samples, it doesnt show peak each time.
What is your recommendation for this problem?
Hello everyone
Based on the calculation of the enthalpy peaks of crystallization and melting of the DSC test of the provided PLA sample, the crystallinity degree is 12.2%. I don't know if this achieved percentage is logical or not. Kindly, take a look at the attached result and tell me if my calculation was right or not.
P.s = the cooling rate was 30˚ C/min.
Best regards.
Is it possible that the mechanism of stress corrosion cracking(SCC), in PLA is related to factors such as the crystallinity of the polymer, the pH of simulated body fluid, and the magnitude of the applied load?
Best regards.
Hello everyone
I use a metal powder as the filler to a thermoplastic polymer matrix. Therefore, I wonder if there are any changes such as the molecular weight distribution, occurring in the structure by adding the filler metal powder?
My regards.
Hello everyone
I have done a DSC test on the poly-lactic acid by Mettler DSC set-up. As the result shows, there are three endothermic peaks in the red curve that I marked by the black color. It is obvious that peak number one belongs to the glass transition temperature, and peak number three is the melting temperature, but I don't know exactly what is the type of peak number two. I have this concern that the second peak might be the effect of impurity or a metastable modification in the polymer tested.
Any guidance, suggestion, or opinion would be helpful.
Best regards.
More Questions: 2. In what form do the Chemical species reside in the Chromite? Why does the nominal composition of Chromite differ from its Chemical analysis? 3. Chemical species that do not occur in Chromite will occur in other valuable minerals or in gangue. Which Chemical species might these be? 4. What valuable minerals might these be? 5. What is gangue? 6. Is Chromite a mineral or a phase in this instance? If it is a mineral, what is its stoichiometry? If it is a phase, what is its stoichiometry? 7. At what temperature would you need to run the furnace so that the Chromite concentrate (the "charge ") drops into a liquid bath? 8. Is this the temperature at which Chromite furnaces typically run?
Question Guidance:
You are an engineer assigned to a ferrochrome smelter. The principal feed to the furnace is a concentrate of Chromite (nominally FeCr2O4). Once a week the concentrator sends through a chemical analysis of the Chromite concentrate. The following summaries that analysis (in mass %) for one week in the year. Cr2O3 46.3, FeO 20.2, Fe2O3 4.0, SiO2 1.1, CaO 0.2, MgO 11.5, Al2O3 14.5.
Acetaminophen has a λmax of 243 nm. Why is detection λ of HPLC set at 254 nm?
Environmental Earth Sciences (2020) 79:457
I am doing an assay in which Dextran molecules are dissolved in cell culture media (Endothelium growth media - Plus) and the project is being conducted within a BSL3 lab. In order to remove things from the BSL 3 lab, they have to undergo 1 of 3 inactivation processes (Chemical, UV-inactivation, or Heat inactivation). I am reading my dextran molecules via fluorescence so UV will likely ruin the dextran molecules, and heat inactivation is also likely to ruin the dextran fluorescence.
My question: Is there a viral/BS3 chemical inactivation technique that will leave my dextran molecules intact? Formalin? Paraformaldehyde? Methanol?
hi
i want to use sodium borohydride (NaBH4) as the agent for reducing metal ions on CNT and obtain metal-coated CNTs. i have a few questions:
1. if my solvent is ethylene glycol, can i use the same for NaBH4 solution or can i add NaBH4 as powder?
2. how can i calculate the right amount of NaBH4 required to perform this reaction?
Cheers
Hello,
I am looking for chitin reference material for chemical analysis. I found this reference material:
However, I am looking for a second one similar to this one. Does anyone know of a producer/company selling those?
Clement
I used used 1 mmol chloramphenicol as template, 5 mmol MAA and 25 mmol of EGDMA. First I tried in 5 ml of chloroform, it formed partly hard solid and partly slurry after 2 hours.. then I used same mixture but in 50 ml of chloroform, it form slurry.. even I used more chloroform as porogen and solvent, I couldn't get the spericals MIP as mention in some journal.
Why it form slurry and why it form hard solid as I used same amount of chloramphenicol, MAA, and crosslinker?
Whst should I do to get the spericals MIP in large amount so no need to crushed it?
I am looking for bio-based Succinic acid pricing information and would also like to know a few companies interested in buying-selling it.
There is bound to be disparity in the chemical content of ores tested using wet analysis and electronic device placed in direct contact with the dry ores. Do you agree? Let's have your views.
Is it possible to calculate entalphy of LiBr/H2O or another solution if we know correlation of specific heat without using any software?
Why is the enthalpy and entropy values of aspen plus different from engineering equation solver? Are there any conversion methods?
why NIST database in ASPEN PLUS have not LIBR+H2O for experimental data ?
I am trying to model a single-effect absorption refrigeration system using LiBr/H2O in Aspen Plus. Who can help me model the absorption cooling system? Please send a private message.
How can I define the following mixture in Aspen Plus:
"Potassium formate-Water-AL2O3"
If you know, could you please explain step by step via some screenshots from Aspen Plus ?
Although there are already studies in the literature but not much , the use of potassium formate/water or potassium formate+LiBr/Water are not available in the commercial sector for absorption refrigeration systems? what is the actual reason ?
We doubt that some people add urea in fish based food item, any one can suggest some method by which we can detect the uear qualitative and quantitativly.
I am interested in post-synthethic methods of this material, and would like to know the chemical stability of Bi3Te2 (particularly nanotubes) in water, acid o alkaline media.
Any literature regarding this aspect (no matter if it's in bulk) is much appreciated.
Thank you.
How can i increase the pH of sea water to 12? Because when i adding NaOH to seawater the pH does not go above 10 and begins to precipitate.
Hello,
I am having a debate with some colleagues about how we believe a non-stoichiometric oxide would be observed in XPS. Let's say we have an oxide in the form of AB2-x (A = transition metal, B = oxygen), in which x = 0 - 0.5. The sesquioxide AB1.5 has the oxidation state of A(III), and the dioxide AB2 would be the A(IV) state. Would an intermediate phase in a graded stoichiometry (e.g. AB1.75) appear as a superposition of A(III) & A(IV) chemical states, or would it appear as its own intermediate doublet pair? This would mean it has a binding energy for each main line that falls between the A(III) & A(IV) binding energy values, not necessarily being attributed to either of them.
Would the lack of oxygens atoms in the coordination lead to an intermediate mixed oxidation state with A(III) & A(IV) states both present in an amorphous oxide?
My thinking is that even for an intermediate non-stoichiometric oxide, you would still be able to construct a fit from the A(III) and A(IV) chemical species. The contrary thinking is that each non-stoichiometric oxide would be shifted in binding energy position between the A(III) and A(IV) main lines.
Please let me know if I can clarify this question.
Thank you.
I and my friend was conducted a research about primary productivity in fish pond using dark and light bottle. However, we got some problems because dissolved oxygen (DO) in dark bottle after incubation (approx 12 hours) is higher than initial DO. Could someone give us explanation why it happens?
Thank you
The third rotation allegedly leaves the molecule unchanged no matter how much it is rotated, but is it really okay to assume this? A response in mathematics is welcomed, but if you can explain it in words that would be good, too.
I have metal matrix composite containing some unknown amount of hBN. I want to know the amount (wt%) of hBN. Can anyone please suggest the technique like spectroscopy or chemical analysis?
I will be thankful for guidance.
Thanks
How can concentration in terms of rich and poor be affected by adding nanoparticles to LiBr-Water?
what are the drawbacks of using R744 in cascade refrigeration systems compared to R41?
I'm performing a electrochemical experiment, which should produce hydrogen peroxide, what techniques should I employ to reliably detect it from the solution, also what will be the best way to quantify the production?
I would like to analyse monocarboxylic acids higher than C20 (at least up to C30), but I cannot find a company for buying them. I prefer a mixture of more acids in an organic solvent but it can be solid standards. Thank you
I Have directed a doctorate thesis on trials of cultiva tion of Pelargonium graveolens in order tout optimize yields and a quality of chemical compounds of this plant extraits. I need scientific collaboration in chemical analysis and their application on cosmetic or food chemistry, the doctorant Can beneficied a short course. Please to purpose us a laboratory to complete study and prepar a scientific paper.
Thank you vert much.
1.Looking for easy comprehensive and authentic books on analytical chemistry
I am already using
G.D christian
Harris Quantitative chemical analysis
Skoog and west
I just want to explore some book other than these!
2. Do tell me some good precise and easy to understand books on spectroscopy?
Chemical analysis of layers of ice (arctic, antarctic) revealed evidence of climatic changes occurring long before human started polluting our planet-
Recently my supplier delivered steel with the composition 0.04 C, 0.7 Si, 4.7 Mn, 21.8 Cr, 0.5 Cu, 0.45 Mo, 0.3N, 0.7618Ni, 70.2381Fe (chemical analysis report attached ), I am not sure about the grade of the steel as it is magnetic.
I have had great success with Tasmota firmware on a dozen Sonoff basic devices and a couple of TH16s.
I'm looking to go deeper and if possible create code for a chlorine level capacitive level detector.
Using a concept I have used in the past, with a 32 bit 8 core microcontroller, of applying a voltage momentarily to a capacitor to an output Pin, while simultaneously starting a counter, switching that pin from output to input, then when the voltage on that same pin falls to 1/2 VCC the counter stops and that count value is compared. The 1/2 VCC threshold was simply when the state of the now input pin transitioned from on to off.
I'd like to do a similar thing using the ESP 8266 with a couple of large plates on the outside of a plastic chlorine tank and determine the approximate level based on how long it takes to charge this crude capacitor which should vary via tank level.
I'm not looking for super high accuracy like +/- .1" but something +/- .5" would be sufficient.
While I am quite adept at programming in Assembly, my C skills are standard & basic in python.
I'd like to make this part of my Node Red Home Automation system running on a Raspberry Pi so as to monitor the tank's chlorine level via my cell phone.
Anyone use the ESP8266 for this or similar purpose? Ideally I'd like to use a Sonoff Basic as it has the power supply and is self contained. I'd obviously have to add some external leads to the tank's capacitor plates.
I have seen recent papers about this technology. However, the great majoritty these don´t explain the concept in depth. Can anyone help me? Can anyone indicate some reviews about this subject?
Through casual conversation at the Practical Surface Analysis (PSA) meeting this week in Japan, I have become aware that there is still confusion on the availability and accessibility to terms and definitions in surface chemical analysis. While the ASTM E42 vocabulary document, E673, was widely available through most research libraries in the annual volume of ASTM standards, keeping the document consistent with the ISO vocabulary standard for surface chemical analysis, 18115-1, was difficult, particularly since the ISO document was adopting many more terms and growing quickly. It was decided to withdraw the ASTM document and make normative reference to the ISO vocabulary document in ASTM standards.
As part of this change, several people (Don Baer at PNNL and Cedric Powell at NIST in particular) made great effort in getting ISO to agree to make these terms free and readily accessible. They were very successful in getting this cooperation, and now all of the surface analysis vocabulary terms are readily accessible through the IOS Online Browsing Platform (https://www.iso.org/obp/ui). Now there are several sites also hosting links to this, in order to make these terms and definitions accessible. This is a valuable resource, and is freely accessed to check terminology to be used in publications.
This ISO vocabulary document (18115-1) is also being revised, adding new terms and clarifying those that have been found to be lacking information or that are confusing. Please use this resource, and if you find that there are necessary terms missing , or if there is confusion in any of the existing terms, please contact Dr. Alex Shard at NPL, who is the chair of TC201/SC1 and is currently actively revising this document. There is also a companion document (18115-2) for terms used in scanning probe microscopy, and these are also available through the ISO Online Browsing Platform.
Hello everyone,
I'm having some issues with lead acetate solutions for some zebrafish toxicity testing. I'm preparing a stock solution highly concentrated in miliQ water. Then I dilute it to 25ppm (our highest tested concentration) in zebrafish medium (E3, pH 7.2) and the solution looks fine. However, after 24h, when I'm changing the larvae to fresh medium, I have these white precipitates all over on the 24h-old solution. My issue is that I'm not sure my larvae are really exposed to 25ppm Pb. And I can't perform chemical analysis to confirm it.
I wonder if someone else got these issues and what's causing these precipitates? I've also realized the pH decreased which is quite bad for zebrafish larvae (lower than 7.2 is not good for their health).
This is the type of troubleshooting problems that aren't explicit in published papers, so I have no clue if other people are going through the same?
Thank you in advance!
In the framework of the ongoing research project, we will sample pore water from sediments in the mesocosms to investigate on carbon cycling within the system.
Dear Dr. Posz, we are currently working on a project to characterize various Euphrasia spp. chemically by HPTLC, and microscopically, to see if these species can be distinguished by chemical analysis. We are looking for additional samples of Euphrasia, in particular from Eastern Europe since this is where most of the commercial material is collected. In addition, we are interested in authenticated samples of Odontites species, since these are often sold labeled as "Euphrasia".
Please let me know if you are willing to help
Thank you so much for considering this
Stefan
I have made a steel composition and after chemical analysis i found the carbon is beyond acceptable limit however, other elements are within the limit. Is there any way I can remelt the cast structure and add something to bring down the carbon % in steel or may be any other way ?
Lot of research is going on to invent an alternative source of conventional fuel in place of Diesel because petroluem fuels are depleting. Out of which, biodiesels are found to be reliable source of fuel however, this suffers with high NOx emissions. Exhaust gas recirculation has been used to reduce the same. Various forms of biodiesels are prepared and tested (performance wise, exhaust gases and chemical analysis) and found suitable to use in diesel engine. However, there is a limited usage. What could be its limitations in brief?