I Have a Research Support System

There are two main reasons for using deuterated chloroform as a solvent for NMR testing:

On the one hand, it has good solubility to the sample; on the other hand, its residual signal peak in the NMR test will not interfere with the signal peak of the sample.

Before testing, the sample in the NMR tube must be completely dissolved without solid residues.

Therefore, the polymer sample cannot be added too much. It is best to set the solution concentration first, then weigh and confirm the sample quality before adding.

Otherwise, once more samples are added and the concentration of the solution is too high, you have to reopen a bottle of deuterated chloroform to dilute the solution.

Xu Qiu first weighed his five samples, about 4 mg each, and added them to five NMR tubes, then numbered them on the upper wall of the NMR tubes with a marker pen, and finally added 1 ml of deuterated chloroform to each, and capped the bottle stuffed.

One milliliter of solvent can only hold about one-third of the volume of the NMR tube, and the dissolution rate is not fast.

Xu Qiu looked at the dissolving process and found that it was a bit like adding potassium permanganate to the bathtub before taking a bath at home in the early years. The process of dissolving potassium permanganate, the solid materials gradually dispersed in the solution.

After observing for a while, he pressed the bottle stopper and shook the NMR tube back and forth with the force of his wrist to speed up the dissolution of the sample.

A few minutes later.

After all the samples were processed, even the most insoluble P2FBT4T-2BO sample could be completely dissolved, and a total of five sets of dark blue solutions were obtained.

However, the solution concentration of about 4 mg/ml is relatively low.

It is more than enough to test the hydrogen nuclear magnetic resonance spectrum. As for whether the signal of the carbon spectrum can be detected, it can only be resigned to fate.

In addition, when he checked the polymer material he synthesized in the glove box, he discovered a problem.

For the reactions submitted before, because the optimal reaction conditions were not clear, we did not dare to submit too many materials for a single reaction, and the product of each reaction was only tens of milligrams.

Usually, to prepare a solution, several milligrams of materials are consumed.

To do a test, consume a few more milligrams of material.

A piece of polymer was dropped during weighing and a few milligrams of material were still consumed.

Therefore, except for the P2FBT4T-2OD material that has been reacted several times later, there is still ample surplus, and there are not many other materials left.

It seems that in the future it is still necessary to go to Zhang Jiang to do synthesis, but Han Jiaying can be brought along to train this little helper as soon as possible.

...

The two prepared a total of 8 NMR samples.

Chen Wanqing brought a stack of sticky notes, wrote the sample number, solvent, test category, research group, contact number and other information on the sticky notes, and then inserted them into the NMR tube like skewers.

Xu Qiu also followed her example and wrote his sample information on the label paper, then poked a hole in the note paper with an NMR tube, and slipped it on.

This method of labeling is quite unique, where did you learn it from? Xu Qiu teased.

You discovered all of this. When I made an appointment for NMR, I observed the way other people sent samples. Chen Wanqing said:

This kind of NMR tube will not be polluted, and the sticky note is not easy to fall off, and it can leave enough information.

Xu Qiu nodded and said:

Will you send the samples directly to the aging building later?

That's right, send the samples to the MRI room. After registration, they will arrange the tests in the order in which the samples were sent. Chen Wanqing said.

In this case, how do we get the sample data? They will notify them specially, and then we will go to get it? Xu Qiu asked:

There will be no special notification, Chen Wanqing said:

We need to log in to an FTP address on the campus network and find the folder corresponding to the research group we filled in when we sent the samples. The specific address and operation method are posted outside their MRI test room.

If the test is completed, they will name the data file after the test time and upload it in the compressed rar format. We can find the corresponding file and download it. It usually takes about a week.

Xu Qiu subconsciously thought:

Such data transfers are not very secure, since everyone else can see their test data.

After thinking about it, I was worrying too much.

First of all, the files they upload are read-only, and other people can only download them and cannot modify them, so there is no need to worry about the data being tampered with by boring people.

Secondly, the samples tested are all numbered, and others do not know what the samples are.

Moreover, the importance of the NMR test is average, with almost no commercial value, and even if other people get the data, it is meaningless.

After the preparations were completed, the two brought eight nuclear magnetic resonance tubes to the nuclear magnetic resonance test room of the aging building, put them into a beaker specially used to collect samples, registered with the teacher on duty, and completed the sample delivery.

...

A few days later, 216 laboratory.

Besides the light source test, today's elemental analysis is our last characterization test. Chen Wanqing said.

I remember that there are also transient optical absorption spectroscopy and transient fluorescence spectroscopy. Don't we do these characterizations? Xu Qiu said.

You're talking about TA and TRPL. These two devices are relatively expensive. Mr. Wei doesn't have any connections in Shanghai to test them. Chen Wanqing spread her hands and said:

TRPL, nanosecond level response, equipped with a 515nm wavelength monochromatic laser device, about 200,000 is enough, which is still cheap.

And TA is expensive. The nanosecond-level response costs about one million, and the femtosecond-level response costs several million. There are not many places in China that can do TA testing.

Several million, it's so expensive, it's almost the same as the price of a electron microscope. Xu Qiu said with emotion:

I feel that it is not worthwhile to buy an instrument like TA for a research group in the direction of materials. For example, a research group related to optical research in the Department of Physics is not too bad.

That's right, except for those who specialize in TA research, people in other fields will buy one and turn it on once or twice a month, and they will die. Chen Wanqing said:

A key project of the National Natural Science Foundation of China only has a funding of 3 million yuan. The general project funding is 600,000 yuan, and the time is four years. Before the completion of the project, you cannot apply for projects in the same field.

3 million yuan seems like a lot for key projects, but it is extremely difficult to apply for. They are all academicians and Changjiang. It is difficult for ordinary people to beat them, and not all the funds in it can be used to buy equipment.

Relatively speaking, the price of TRPL instruments is relatively affordable.

I heard from Mr. Wei before that a friend of Su University has one. They mainly make perovskite quantum dots. If we want to test it, we have to go there by ourselves.

Junior, are you interested in going to Sioux City for a business trip?

Xu Qiu thought about the documents he read before, thought for a moment, and said:

Let's forget it, I feel that there should be no need to test TRPL for the time being, and I won't get much useful information.

Fluorescence spectroscopy is used in the field of organic photovoltaics, mainly to calculate the fluorescence quenching efficiency of donor and acceptor blend films, and ordinary steady-state fluorescence spectroscopy is currently sufficient.

That's true.

Thanks to Lan Shiyu for rewarding 500 starting coins, and Apple Fighter and Ye Ziluo for rewarding 100 starting coins.