Answer:
① There are many test methods: many kinds of NMR test methods, including one-dimensional and two-dimensional, have been widely used in structural analysis and material identification; quantitative analysis is no longer limited to 1H NMR experiment, and quantitative analysis of heteronuclear and even two-dimensional NMR appears frequently;
② There are many calibration targets: most compounds have multiple sets of NMR lines, which can be used as calibration targets for quantitative analysis theoretically, which undoubtedly provides convenience for the processing of test data;
③ There are many types of quantitative information: in the literature reports, not only the integral area or intensity of the resonance spectral line is used as the data parameter of NMR quantitative analysis, but also the change value of chemical displacement under specific conditions can be used as the parameter of content determination;
④ There are many reference modes: nuclear magnetic resonance obtains the data information of quantitative analysis through direct comparison of signals. In the experiment, multiple modes such as internal standard, external standard, solvent calibration and physical calibration can be used to provide reference signals. In the determination of relative content, the mode of sample self-standard can also be used.
In a word, NMR is a mature analytical and testing method with distinct technical characteristics, multiple means, flexible methods and rich information, which has a strong competitiveness in drug analysis and identification.
Explanation:
http://www.creative-biostructure.com/nmr-services_28.htm
Answer:
We can look in the sky in the west in the evening or it will rise before the sun in the East.
Around 6am
Answer:
The answer is A
Explanation:
There are certain types of proteins that need to be sinthesized in the rough ERC in order to reach its final destination. These proteins are:
- Proteins that need to be exported from the cell.
- Proteins that need to be docked to either endomembranes or the plasma membrane.
- Hydrolytic lysosomal enzimes.
- Proteins that have a function in the lumen of certain organelles such as the endoplasmic reticulum, golgi or the nuclear envelope.
Hemoglobin doesn't fit in any of these cateogories, given that it is a cytoplasmic protein. Therefore, its synthesis begins and ends in the cytoplasm, where the protein performs its function.
Two atoms that contain the same number of protons but different neutrons are isotopes of the same element.their masses are different but they react the same way chemically
