Chapter 203: Wudu fresh duck blood and red fermented bean curd bibimbap

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After returning to Handan campus in the evening, Xu Qiu went directly to Room 218.
As soon as he walked in, Teacher Wei pointed to the empty utility room next to him, "I have already made room for the instrument."
‘I didn’t expect Teacher Wei to be so proactive. He thought it would take a lot of talking. Xu Qiu nodded repeatedly, walked to Teacher Wei's desk, opened the WeChat chat record between him and Qiu Heming, and said, "This is the description and quotation of the TRPL instrument."
Then he compared the files in the phone and relayed the results of discussions with the senior sisters and senior sisters to Teacher Wei in the afternoon.
Teacher Wei was very satisfied in general, but only mentioned that when designing the sample compartment, an extra interface was needed to connect to the cryogenic device in the laboratory. This cryogenic device was from the laboratory of beautiful country. He brought it back and left it to Tian Qing to take care of it. Xu Qiu had only seen the appearance of the instrument, which was in the shape of a long column, but he had never used it, and naturally he had not considered this.
After the two had communicated, Wei Xingsi nodded: "Okay, then I will call Qiu Heming now and set this matter down."
Qiu Heming answered the phone, and Wei Xingsi went straight to the subject, indicating that he would buy the instrument and hope to get it as soon as possible.
Afterwards, the two talked about other transaction matters. After all, it was about 200,000 instruments. The procedures were quite cumbersome. For example, it was necessary to prepare a formal purchase contract, to file with the department, and to do fixed assets, reimbursement, etc. Yes, of course Xu Qiu doesn't have to worry about these things.
In addition, Mr. Wei also mentioned the modification of the sample cabin and asked for matching optical lenses, dimming mirrors, filters and the like. Although they are all gadgets, Lin Lin always adds up to several thousand yuan.
Qiu Heming hesitated for a while, but still agreed, as if it happened to be stuck on his bottom line.
Xu Qiu watched the whole process. His recent experience has deepened his understanding of Teacher Wei and gave him a shrewd and resolute feeling.
Before that, he actually hadn't had much direct contact with Teacher Wei, and in most cases he would be separated by Senior Sister Chen Wanqing.
After the beginning of this semester, Teacher Wei took him more and more seriously, often communicated directly with him, and handed over the purchase right of such a large instrument to him, as if he had been treated as a doctoral student in advance.
...
The next morning, Zhang Jiang laboratory.
Han Jiaying looked at the indescribably agitated red sticky substance in several reaction flasks, and asked:
"Brother, the reaction time is not enough for 24 hours. I want to shut down the reaction now, or write a summary for a while and talk about it in the afternoon?"
"Shut down now, there are four reactions, maybe there will be four pillars today, I'm afraid that the time will be too late," Xu Qiu made a judgment after thinking for a moment, and then explained:
"Moreover, the reaction we are investing now is not as delicate as the polymerization reaction we did before. This small molecule reaction is reduced by four or five hours, which is only equivalent to shortening the reaction time by about 20%, which may reduce the yield by several percentage points. Rate, it doesn’t matter.
The two shut down the reaction. During the cooling of the reaction vessel, Xu Qiu took the initiative to say: "For safety, I will order a plate to see the purity of the product, and the results of the plate can be used as a reference for waiting to pass the column."
Han Jiaying nodded. She has been on "Organic Chemistry Experiment" and is naturally familiar with the point-and-board method.
The so-called point plate method is a common name, and the name of a written point is thin layer chromatography.
The principle is similar to that of liquid chromatography. It uses a support coated on a support plate as a stationary phase (such as silica gel on a silica gel plate) and a suitable solvent as the mobile phase (chromatographic fluid) to separate mixed samples. A chromatographic separation technique for identification and quantification;
The difference between the two is that in the spot plate method, the chromatography fluid moves from bottom to top, while the liquid chromatography method usually moves from top to bottom.
"Brother, let me prepare the chromatography bottle and the chromatography solution." Han Jiaying paused, "By the way, how do I prepare the chromatography solution?"
"Petroleum ether: dichloromethane 1:1 volume ratio." Xu Qiu said casually, because it is the first time to explore, so he is not very clear.
After speaking, he found the silicone plate in the laboratory, which is a glass plate coated with silicone, and then cut it into a strip of 2 cm by 5 cm with a glass knife, and then used a pencil to move the upper and lower edges of the silicone plate. Use a ruler and pencil to lightly draw a line at a distance of about 1 cm.
Next, he took several disposable centrifuge tubes, each filled with about 1 ml of dichloromethane, and then used a clean capillary tube, which is a thin tube with an inner diameter of 1 mm or less, to take out an appropriate amount of product in the reaction flask, and It is dissolved in a centrifuge tube, and then the sample name is marked with a marker.
After completing these two steps, the school girl has also prepared two chromatography bottles and chromatography solutions.
The cost of this plate method is very low. Compared with the 100,000 yuan instrument of liquid chromatography, it looks a little bit worse, but the doorway inside is not small.
If the polarity of the chromatography solvent is too high, the sample will climb too fast and it is difficult to separate;
If the polarity of the solvent is too low, the sample will not climb and it will be difficult to separate;
If the sample concentration is too high, tailing will be formed, which will affect the judgment;
If the sample concentration is too low, it may not be detected, which will also affect the judgment.
In short, it is a craft.
Fortunately, Xu Qiu deliberately went to the aging building before and found Associate Professor Qian Xingquan who taught him "Organic Chemistry Experiment". He copied 50% of the other's fifth-level organic chemistry experiment skills. This is the highest level of skill he has seen so far. Teacher.
Teacher Qian is now more than 50 years old. He has very good people. At least he is very responsible in teaching. Perhaps he knew that his scientific research ability was insufficient. He did not insist on doing scientific research on the front line. Instead, he switched to teaching experimental courses. Just over ten years.
With the fifth-level 50% proficiency system teaching, Xu Qiu didn't panic in the face of small experiments such as point board.
Everything was ready, he used a clean capillary tube to the sample solution in the centrifuge tube, then used the capillary tube to vertically place samples on the previously drawn pencil line, and finally put the silica gel plate into the chromatography solution vertically.
The chromatography fluid contacts the silica gel plate and starts to climb from bottom to top. After the underdraw, the solvent drives the sample in the upper sample point to climb.
"Not bad, the chromatography solution is just right." Looking at the preliminary results, Xu Qiu nodded in satisfaction.
"Okay, I'll try it too." Han Jiaying also followed Xu Qiu's way, picked a piece of silica gel, and started to sample.
When the chromatographic solution reached the upper drawing, Xu Qiu immediately took out the silica gel plate, and after the solvent adsorbed on it evaporates, irradiated the surface of the silica gel plate with a UV lamp, and then marked the place where fluorescence was generated with a pencil.
Aromatic compounds such as benzene rings, large conjugated systems, and nitro-containing substances will all develop color under ultraviolet light.
Although it can sometimes be judged with the naked eye, some colorless samples with less content can also be detected with ultraviolet light.
The final result is two sample points, one deep and one shallow, one in front and one behind.
It shows that there is one main product and one by-product, and the yield is not low, and the separation effect is also good.
Soon, the results of the four reaction products came out. Except for Xu Qiu, the other three are:
One deep and one shallow, one after the other;
One is deep and the other is shallow, but the two points rise slowly and partially overlap;
Two deep, one after the other.
Obviously, the results of the last two points are problematic.
It’s okay to say that the one that rises slowly, just increase the polarity of the chromatography solution. Xu Qiu prepared a petroleum ether:dichloromethane 1:2 volume ratio chromatography solution. , The result becomes one deep and one shallow again, one after another.
The two-deep one is more difficult to handle, which means that there are two main products of the reaction. Although it is not difficult to separate, the yield may be worrying, perhaps less than 50%.
This is a school girl's system. Obviously she also knows what it means, and said bitterly, "Brother, what should I do?"
"Don't worry, there is still a chance." Xu Qiu comforted, and then analyzed: "Perylenetetracarboxylic dianhydride and imidazole raw materials should not be a big problem, because other reactions use the same raw materials but it is normal. Then there is a problem. The local probability is the amine molecule."
"Yeah, it's probably because the amine molecules have been added," Han Jiaying nodded, and then fell into thinking: "But I didn't have any mistakes in the experimental operation at the time."
"I thought of two possibilities. One is that the materials you mentioned are less added, and the other is that the molecular structures of different amines are different, and the reactivity will be slightly different." Xu Qiu suggested:
"On the one hand, add some amine molecules in, and on the other hand, increase the reaction temperature to 160 degrees Celsius. The two proceed simultaneously. Before leaving tonight, I will check the board. Anyway, small molecules can withstand the toss."
"Okay, it's still the brother's thoughtfulness." Han Jiaying nodded happily.
"I am also to blame, I still have less experience," Xu Qiu reproached himself: "If you clicked the board before leaving yesterday, you might be able to discover the problem in time and remedy it in advance."
"Senior brother, don't think so," Han Jiaying explained: "It's already very good now, at least there is a possibility of remedy, I just planned to respond directly again."
...
Han Jiaying completely referred to Xu Qiu's suggestion, and dealt with the response of the double-deep result.
Subsequently, the two post-processed the other three normal reactions.
"Remember the post-processing method."
"Of course I remember, first add water, then extract with dichloromethane, finally separate the liquids, and spin down... Well, it's written in the literature."
"That's right, adding water is mainly to remove imidazole, and dichloromethane can extract the product." Although Xu Qiu knew that the school girl should be familiar with these safety knowledge, he still subconsciously reminded:
"If you want to use dichloromethane, let's operate it in a fume hood. Take care to protect yourself. Don't get the solvent in your hands. Dichloromethane can't stop it."
"Okay." Han Jiaying nodded seriously.
The toxicity of methylene chloride is much lower than that of chloroform, so Xu Qiu did not choose to wear a gas mask.
If possible, he is reluctant to use these toxic solvents. Most solvents have potential carcinogenic risks.
However, their performance is really good, and there are no substitutes.
This is also a risk that must be taken in the field of organic synthesis.
However, at least the reagents used in the experiment can be checked for their physical and chemical properties through MSDS, and various protective equipment has been developed. The safety of experimenters can be guaranteed to a great extent.
In the early days of research, for example, in Madame Curie’s time, radioactive elements were just discovered, and they didn’t know anything about their properties.
Wealthy people even carry radioactive substances as "amulets" and other things close to their bodies, or as "luxuries" everywhere.
These behaviors really caused the birthday star to hang his neck—too much life.
Xu Qiu added about 150 ml of water and 150 ml of dichloromethane to the two reaction flasks, and then poured the mixed liquid into a 500 ml separatory funnel.
Shake slightly a few times, then open the stopper above the separatory funnel to deflate.
After all, the boiling point of dichloromethane is too low. If it is shaken for many times without degassing, the pressure inside the separatory funnel is too high, which may cause the liquid inside to directly open the plug and spray out.
After mixing well several times, he put the separatory funnel on the shelf and let it stand still.
After the solution is separated, the upper part is a slightly yellow transparent aqueous solution, and the lower part is a red dichloromethane solution.
The reaction product is mainly dissolved in methylene chloride, so he opens the valve under the separatory funnel to collect the solution.
After washing twice with water again, pour it into an eggplant-shaped bottle for later use.
Han Jiaying only had one reaction, so after the early end, she ran to Xu Qiu to watch.
"Wait for me, my second reaction will be handled immediately." Xu Qiu took the initiative.
"Brother~EbookFREE.me~ Your solution is so bright red, a bit like..." Han Jiaying paused, "It looks like duck blood in the fog."
Xu Qiu was taken aback, she could even think of food.
"By the way, brother," Han Jiaying raised her hand and raised the sleeve of the lab coat, "I just accidentally got PDI on the lab coat a little bit, it shouldn't have any effect."
Xu Qiu glanced at it and said,
Fortunately, it’s a lab coat. If you get it on, the clothes are basically useless. This is a dye intermediate with strong adhesion, but very low toxicity.

"Um... this way, that's good."
Before long, Xu Qiu transferred the extracted and washed solution to the eggplant-shaped bottle and said, "The second one is done, too. Let's prepare to mix the sample."
"Hey, what is the dressing?" Han Jiaying curiously asked, "Don't we get the product by spinning directly?"
Xu Qiu didn't know this operation before, but he knew it after seeing the system's video. He explained patiently:
"After passing through the column, the sample needs to be evenly distributed, and the sample that is directly steamed may not be uniform. If a certain proportion of silica gel is mixed, then the sample can be evenly distributed in the silica gel."
"It turns out that this is the case, so how much do you want to add?" Han Jiaying nodded.
"We calculate according to 5 grams of product, the general mixing ratio is 1:1 to 1:2, the middle value is to add 7.5 grams of silica gel, and use 100-200 mesh silica gel." Xu Qiu took out the silica gel from the reagent cabinet. After weighing, add to eggplant-shaped bottle.
Rotary steaming is then performed to obtain a red solid powder.
"Does it look like red fermented bean curd bibimbap?" Xu Qiu was suddenly inspired.
"As expected, brother, what a real image!"
"You two, that's enough, I have to eat later."