Chemical Analysis - Science topic

Hi. Now I need to get the SMILES of ~1000 chemicals but I only have their names (e.g., ethanol). The only way I know to generate SMILES is from PubChem but I can only make 1 query at a time. Doing 1000 queries one by one is time-consuming. Is there any tool to batch convert chemical names to SMILES? Thank you!

I've been trying to make a solution out of DMF, Fmoc-osu and Glycine. For protection of glycine. I have a hot plate with a magnet and an ultrasonic machine. But nothing is working! I have also been trying to slowly add water to the mixture but Fmoc-osu precipitates as soon as i mix it. And it turns into a big mess. Please help me!

I have a question about chemical analysis ICP sample preparation.

A 16g liquid sample was evaporated on a hot plate to obtain 0.9409g of salt.

Here, 4g of 2% HNO3 was added to completely dissolve the salt obtained from IPA, and analysis was performed.

At this time, the final concentration calculation must be multiplied by

Is the dilution factor 4.3042 correct? or is 0.2129 correct?

used to calculate

The density of the sample is 0.785g/ml

The density of 2% HNO3 is 1.01 g/ml.

Since the sample is reduced from 16 g to 0.8g, is 0.2129 correct considering the initial volume?

Or is 4.3042 correct by calculating the sample volume after digestion?

How can I calculate the molar ratio of Mg:P and N:P from the concentrations available in the attached table? Thank you

My question about the struvite precipitation (MgNH4PO4): Is the molar ratio of Mg:P the same as Mg: PO4, and N:P the same as NH4:PO4? Otherwise, Do I have to make any calculations when I convert from one form to another, like Mg:P to Mg: PO4? Thanks!

If the Molar Ratio of struvite Mg2+:NH4+:PO4 is (1.6:1:1.2), how can I calculate the molar ratio of Mg:P and N:P? Thank you very much

I'm looking for something that can inhibit the reduction of FeIII for experimental research. Please help me if you know it.

I want finding metallurgical length of high alloy steel in continuous casting.

what is difference between living and non living ?life and death?#molecular concept

I wanted to know the AoAC protocol for analysis of the p-anisidine value of fish oil.

Hi dear colleagues, I am a highway consultant and I have no knowledge to understand the results in the attached file, so please, I want to interpret the results of the chemical analysis of rock asphalt which I used in my research paper. with my regards

What type of chemical interaction can occur if more than 2 pollutants are present in the ambient air, which can affect the human health, especially in pregnant women?

Quantification of EDX spectra of Al-based casting alloys it was found certain intensity of Zr (up to 0.7 wt. percent) whereas the chemical analysis showed only very little Zr content (0.05). EDX were performed using Talos 120 TEM. Any Zr-enriched precipitates were not observed. I am looking for an answer why Zr intercity appeared in the aluminium matrix whereas it can't be. Many thanks in advance

I am searching for papers to get an overview of different approaches on longitudinal sampling strategies. For me, it would be important to know how they deal with wastewater treatment plants, inlets from other streams and urban areas. I want to identify differences in chemical pollution within one stream.

Hello everyone,

I want to calculate a ratio, but for some measurements, I have <LOD in the denominator

There is actually a range of possible numbers <LOD

One solution could be to consider: =LOD, or LOD/2, etc. ?

Are there methodological references which I can confront?

Thank you in advance

Hello everyone,

I want to calculate a ratio, but for some measurements, I have <LOD in the denominator

There is actually a range of possible numbers <LOD

One solution could be to consider: =LOD, or LOD/2, etc. ?

Are there methodological references which I can confront?

Thank you in advance

The demand for ready- to- eat food is increasing worldwide. Fresh foods are facing challenges in terms of their limited shelf life, association with food borne diseases and outbreak. This results in commercial pressure from consumers on the use of synthetic chemicals as food preservatives. A wide range of synthetic additives are used as preservatives in food industries in order to increase their shelf life and inhibit bacterial growth. However, use of these synthetic chemicals is causing health threats to consumers. Plant antimicrobials are getting into potential interest as a good alternative over synthetic food additives. Limited research has been done on the use of pine antimicrobials in food industry. This research will focus on the use of chemical analysis by qualitative and quantitative techniques in extracting plant antimicrobials (the phytochemicals) from Pinus caribaea needles var. hondurensis, in order to shed light on its potential usage in food industry as a natural food preserving additive. Pinus caribaea needles will be collected from Fiji Pines forest stations (Lololo, Ra, Nabou, Nai, Bua, and Maduata forest stations, and nurseries: Ra, Nabou, and Nadi) of different ages (3 weeks- 6 months, and 5, 10, 15, and 20 years) of the tree. Chemical analysis will be conducted via qualitative (use of chemicals), and quantitative (UV Spectrometry and Gas chromatography, Gas chromatography/ Mass spectrometry) techniques. The effect of the age of the pine needles and its environmental factors on the quantity of phytochemical extraction will be considered. This finding will assist in potential usage of plant antimicrobials extracted from Pinus caribaea needles var. hondurensis in food industry as a food ingredient, and further in- depth research can be continued on this limited research present in literature.

looking for collaborations in writing review papers and ideas in doing this project. Thankyou

thank you

What are the factors that increase the thickness of the chemical coating with nickel. In Standard about 20 micrometers. I have to aim for a coating thickness of 80-100 micrometer. Any suggestions

Hello friends

Iam doing a project based on chemical analysis of Pinus Caribaea leaves and the potential uses for tea consumption

Looking for some collaboration for writing review papers and project

Vinaka

I want to check the presence of cadmium ions in a complex by doing a Chemical analysis, kindly suggest a method.

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

The idea is to relate the analysis with different urbanization indicators and land uses.

Hi there,

I'm currently doing research on the compsition of the liquid phase generated by thermal degradation of Poly(methyl methacrylate) (PMMA).

In my group we are especally interested in finding the monomer methyl methacrylate (MMA).

But from literature I have kind of a clue what else I can expect to be in the mixture,

like methyl propionate, methyl isobutyrate and other carbonyl-, ester- and diester-compounds.

Their boiling points should range between 50 °C and 270 °C and I consider them themally stabel.

Now I thouhgt on first analyzing the samples with GC-MS, because the GC allows to seperate the different compunds and MS will help me to characterize those compounds.

The problem is, that I've never done GC-MS before and I'm a bit puzzled if I have to dissolve my sampels or if I can probe them directly?

Is there a benefit in using a solvent?

And what requiremnets should a solvent fullfil, apart form dissolving my sample and beeing thermally stable, especally regarding the boiling point?

Thanks already for your suggestions!

It is known that essential oil yielding plants belong to some specific families such as Lamiaceae, Lauraceae and so on. Is there any specific criteria to identify such oil yielding plants in field without chemical analysis? For survey of such plants?

FT- IR can be used as an advanced analyser for chemical analysis,

So which parameters do I detect for the chemical analysis of mustard oils?

Hi Everyon,

We are using ionic deposition to coat a mix of metals on a plate. We like to map the metal compositions on different parts of the plate or at least before they hit the plat (ionic form). What’s the best way to do this without taking off the coating from the plate as we want it to stay intact…

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

chemical analysis

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

How do you calculate fixed carbon in biomass?

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

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.