actually It's depend on the type of your unknown ? is it solid , liquid or gas phase . organic , inorganic or bio-organic molecule .clarify the physical properties of the unknown that will help. generally .FT-IR + H-NMR+ C-NMR , HPLC, GC and Mass analysis ...etc all of these technique will help to elucidation your unknown product .
actually It's depend on the type of your unknown ? is it solid , liquid or gas phase . organic , inorganic or bio-organic molecule .clarify the physical properties of the unknown that will help. generally .FT-IR + H-NMR+ C-NMR , HPLC, GC and Mass analysis ...etc all of these technique will help to elucidation your unknown product .
Most journal accept the following:
H NMR, C13 NMR, High Res Mass, Elemental Analysis, Melting Point, IR. IF you have all these you are good to go. This is speaking from a molecular organic perspective of course.
if your compound is unknown better you will go step by step such take HPLC report( for purity) along with UV spectra and then predict which type compound ( aromatic or non aromatic ) after that sample send for 1NMR and MASS (tentative chemical str and mass of compound ) this data compare with literature. if sample don't match with report data again you will take 13CNMR, 2DNMR and HRMS interpretation of stra nd compile data.
Of course, 2D NMR is standard these days and should be done at the same time as C13 NMR. Of course, a crystal structure is most convincing, but remember it doesn't prove purity only that the crystals came out of solution in that particular structure. However, if you can get enough single crystals and perform the rest of the characterization from them, you have it. Also, these days I am all on about how elemental analysis doesn't always work. For Chemcomm, you can substitute analytical HPLC and high res mass for EA. I consider this a journal of record for chemistry. So follow those requirements.
X-ray crystallography?
If your compound can crystallize and have access to this facility, X-ray crystallography is the ultimate technique to determine the structure.
The (viscous) compound's solubility need to be checked in different solvents such as methanol, chloroform, water, dimethyl sulfoxide, dichloromethane, acetonitrile. Accordingly, the sample can be submitted to NMR data acquisitions in appropriate solvents. Initially, one dimensional (1D) proton (1H) NMR needs to be acquired. Depending on the data quality of 1D 1H-NMR, a few other NMR experiments can be carried out, such as 1D 13C-NMR, 2D 1H-1H COSY, 2D 1H-13C HSQC or 2D 1H-15N HSQC. Mass spectrometric data also will be useful, from which it may be possible to know intact molecular mass. From high resolution mass spectrometric data, molecular formula (elemental composition) can be shortlisted. The shortlisted molecular formula can be correlated with NMR data, i.e., no. of carbon atoms, hydrogen atoms, nitrogen atoms or phosphorous atoms. To verify the presence of phosphorous, 31P- NMR experiments may also be planned. Did you do TLC? From TLC, the level of purity of the compound may be known? If the sample is not pure, then NMR data have to be interpreted carefully because the signals in NMR spectrum can be contributions from more than one molecule.
In my view kindly follow the techniques such as TLC, Melting/Boiling Points (compare with Literature Value), IR, GC/HPLC, Mass, NMR.
Kindly know purity of your compounds on some primary techniques as subsequently mentioned above.
Spectroscopic methods (UV-VIS, IR, NMR, Raman, Mass spec) can give you structural information on your sample. Elemental techniques, such as atomic emission, graphite furnace AAS, ICP, X-ray etc, could give an indication to a wide variety of elements within a sample. Once you have some idea about your sample from spectroscopy, maybe then consider moving into separation techniques such as HPLC, TLC, GC etc, whatever your sample allows.
X-ray crytallography does not characterize your sample, it only gives information on a component of your sample that forms single crystals. You may have a mixture of diasteriomers where only one crystallizes, for example. ITs either a strong lead or a final conclusion in conjunction with NMR and MS, but on its own, not complete.
Identification techniques are FT-IR, NMR and MS.
In case of the biosurfactant I would go with MS.
Dear Bharadwaj madam: I do not know from which field of engineering you are . However, let me explain, From your hypothesis, you will have some tentative compounds that you expect to get during your research. Keep this list always in from of you. Draw the structures of each of these compounds too. Now to start with if these are solid compounds, simply run a TLC or if you have HPTLC then run it too. In case it is a liquid compound, you may need to run a HPLC. Do not use GC alone. It will not only give you the RF / RT value but also the UV absorption peak. Now run a simple GCMS. In case you are not satisfied with it the see if can run a LCMS or MS-MS. It will throw some light on the molecular weight of the compound. In case it is not possible to purify it very well, then I would recommend that you use any of the MS but with TOF. After this run FTIR of the compound to confirm the functional groups that might be present in the compound. Your search should end here. However, if it still doesn't answer your question the run FTPMR, FT13CNMR and if required the other NMRs like FT19FNMR etc. Interpret all the data and you should get the desired answer. Good luck.
Dear madam pls find out the which methods is suitable for unknown sample analysis in the method of HMBC-FITR it is better method.
Dear madam pls find out the which methods is suitable for unknown sample analysis in the method of HMBC-NMR it is better method
I think best way to elucidate the structure of an unknown compound is through X-ray diffraction analysis if compound is either amorphous or in crystalline state.In case of liquid UV, IR, Mass and NMR combined are are best to solve the structure of a compound
If it is a solid, then, XRD would be one of the best to start with. Otherwise, for liquid: IR, UV, NMR etc are good enough.
For complete characterization of an unknown compound, many techniques will have to be used. We need to pool the data from different equipments to get a complete answer. Both Chromatography and Spectroscopy equipments will have to be used. Some of the important equipments will include UV, FTIR, LC, LCMSMS, NMR, XRD etc
Your going to be analysis to the unknown compound. The characterization of an unknown compound to use techniques for XRD and NMR techniques HMBC-NMR.
If your material is biosurfactant: There are some ways:
1: If you have LC-MS system, you can easily get the structure.
2: If not, you first have to purify the material with for example TLC or column chromatography. Then analyse the pure sample with FTIR, CNMR and HNMR. In this way you can get the structure. If you can get Mass spectra the result is more reliable.
If unknown compound is crystalline solid,X-ray diffraction technique is best for elucidating the structure. In case the compound is liquid, use of combind IR, UV, Mass and NMR techniques are sufficient in solving the structure.
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