What chemical do you want to test? Molecular structure? Can be purified to 890%, the higher the better. A small number of impurities can be distinguished by NMR! Too many impurities will interfere with the analysis of NMR spectrum, but it is not serious; It greatly interferes with the carbon spectrum of nuclear magnetic resonance.
There are many nuclear magnetic resonance and carbon spectrum detection methods! It depends on your purpose; It depends on how much you expect to spend on the exam!
The sample is pure and simple enough to test the hydrogen spectrum. This is for organic compounds. For inorganic compounds, nuclear magnetic resonance is not the first choice for detection methods.
For slightly more complicated organic compounds, carbon spectrum can be added.
No matter how complicated it is, it can be measured:
Deep carbon spectrum: CH3, CH2, CH and quaternary carbon can be distinguished.
H-H COSY chemical shift correlation two-dimensional spectrum; Explore the relationship between hydrogen and hydrogen;
C-H COSY or HMQC spectrum and hydrocarbon correlation two-dimensional spectrum to explore the relationship between hydrocarbon bonds;
HMBC spectrum, two-dimensional spectrum of hydrocarbon remote correlation, explores the relationship between two bonds, three bonds, four bonds, ..., seven bonds between hydrocarbons;
These spectrograms are the most effective and cheapest methods to identify and confirm some complex drugs.
If fluorine, phosphorus, nitrogen and other elements are contained, fluorine (F- 19), phosphorus (P-3 1) and nitrogen (N- 15) can be measured by nuclear magnetic resonance.
For research and published papers, there are many multi-pulse spectra and related two-dimensional spectra of NMR.
Mass spectrometry, drugs must be pure! If any small intensity peak near the most important molecular ion peak is disturbed by impurities, the judgment that important conclusions such as molecular formula and molecular weight can be obtained will be lost!
The sample has high purity and can be detected by conventional mass spectrometry. You give the sample to the tester and tell him the possible molecular weight, melting point, boiling point and other information of the sample, and he will help you choose the test spectrum.
If the sample is impure or impure and has a low boiling point, gas chromatography-mass spectrometry can be used;
If the sample is not too pure or pure and has a high boiling point, you can do liquid chromatography-mass spectrometry;
Mass spectrometry, different from sample ionization system:
Electric shock source, EI),
Chemical ionization source (ci),
Field ionization, FI),
Field desorption ionization source (FD),
Fast atomic bombardment,
Liquid secondary ion mass spectrometry (LSI),
Electrospray ionization mass spectrometry (ESI-MS) and thermal spray ionization (HSI-MS),
In addition, there are
Ion trap mass spectrometry (ITMS),
Multistage mass spectrometry (MS~n),
TIC (total ion flow chromatography (TIC) diagram), EIC diagram and multi-stage mass spectrometry combined with liquid chromatography technology,
Time of flight mass spectrometer (tof),
Inductively coupled plasma mass spectrometry (ICP-MS),
Wait,
You can search online to enrich relevant knowledge first, or you can discuss the testing problems related to your samples with professionals when sending samples.