Barcelona

19 hours ago, hypervalent_iodine said:

It was over 2 years ago, there’s really no point. 

 

I more meant why do need this specific chemical in such amounts?

There are certainly cheaper and easier ways of learning about synthesis.

Should it because I think chemical synthesis forums be more practical than books, some issues mentioned in forums may not contain in the books.

1 hour ago, hypervalent_iodine said:

No point. I have no idea why they did it. 

You mean like a discussion forum like this one? Chemical forums is good. Can I ask what you're needing this stuff for? 

you should ask them about it if it is really important, maybe they thought it was nothing, but I also disagree their ignorance of the label and package without any reasons.

I want to know more about chemical synthesis, and collecting as many as sources is what  I usually do when I began to start a learning project.  haha

On 1/7/2020 at 3:45 PM, hypervalent_iodine said:

I wouldn’t call 5 kg a small scale by any stretch. I can have a look tomorrow, but you could try Oakwood if you’re located in the US. There are other companies that specialise in small heterocycles that might be worth looking at, but 5 kg is quite a bit and I wouldn’t expect it to be cheap. Maybe not sigma prices, but not too much under that. You can sometimes find random Chinese companies that will do it for much cheaper, but you pay for that at your own risk. 

If you have access to SciFinder, the supplier search function can be useful.

and do you know any other forums containing chemical synthesis, I cannot find more, I want to know more about this , I am just a beginner. Thanks!

34 minutes ago, hypervalent_iodine said:

过去，我是从随机的中国公司订购产品的，实际上我确实收到了我想要的东西，但是它们的包装和标签还有很多不足之处。我在一个拉链锁袋（!!）中收到10克米色粉末，上面带有完全不同的标签。海关申报表说这不是事实，这显然是非法的。价格绝对值得（600美元而不是3k美元），但是我们不会再向他们订购。我有朋友从那里的其他公司订购抗体，并收到了罚款，但包装上说他们正在运送空管。就像我说的，您可以向他们订购，后果自负。 

okay, thanks. ::)

6 minutes ago, Barcelona said:

and do you know any other forums containing chemical synthesis, I cannot find more, I want to know more about this , I am just a beginner. Thanks!

okay, thanks. ::)

have you asked them why they used different label? was that because the powder looks like hard drugs?

On 1/7/2020 at 3:45 PM, hypervalent_iodine said:

I wouldn’t call 5 kg a small scale by any stretch. I can have a look tomorrow, but you could try Oakwood if you’re located in the US. There are other companies that specialise in small heterocycles that might be worth looking at, but 5 kg is quite a bit and I wouldn’t expect it to be cheap. Maybe not sigma prices, but not too much under that. You can sometimes find random Chinese companies that will do it for much cheaper, but you pay for that at your own risk. 

If you have access to SciFinder, the supplier search function can be useful.

Thanks. I made a mistake, not 5kg, but 500g. Thanks for your advice. And SciFinder is of great help. Have you ever outsourced your project to a Chinese company since you said it may take a risk?

6 hours ago, hypervalent_iodine said:

There are plenty, but it depends a bit on what exactly you need, why you need it, and who you are / who you are affiliated with.

Yeah, you are right, I should list  the info you mentioned, and choose the most suitable company to work on my project. 

I need the chemical (CAS NO: 871836-51-0) for 5 kg, and need the price lower than sigma aldrich.

Attached is the chemical structure.

Can someone recommend a trustworthy company that provides synthesis service of small scale.
I have asked several companies, but they only do larger scale synthesis. 
Any comment or recommendation will be highly appreciated.
Thanks!

20 hours ago, chenbeier said:

For this issue there are different analytical machines available, like gas chromatography, UV, IR spectroskopie, nuclear magnetic resonance and others.

To remove the pesticides there is only one way, they shouldnt bring induring growing and harvest of the fruits.

I know HPLC columns, SPE cartridge, and flash columns. If I want to detect pesticide residue in bananas, I should chose SPE., right? Do you know QuEChERS.. does it work fot the detect process?

5 hours ago, chenbeier said:

I think here kitchen work was meant. Of course this will not remove pesticides in the fruits.

Put some salt into water and wash the fruits, we ususlly do in this way in China.

19 hours ago, Sensei said:

I already explained my idea how to not have to use pesticides at all, in couple other threads.

https://www.google.com/search?q=scienceforums.net+sensei+farmer+skyscrapers

Basically there are needed hermetic farmer skyscrapers. If bugs, fungi, microbes get in some floor, just one floor must be decontaminated.

They could also reduce needed water and power usage. Reduce to zero losses caused by flooding, hail or ground frost.

 

Pesticides kill not just unwanted organisms but also kill bees and other insects required for reproduction of plants.

This caused major issues in e.g. China.

https://www.chinadialogue.net/article/show/single/en/5193-Decline-of-bees-forces-China-s-apple-farmers-to-pollinate-by-hand

 

I feel the same way,, but in China, pesticides are still popular. Farmers are less here, they all go to the city for living. It is a trend. and may continue for several years..People use pesticides as a quick fix, but it is against the nature. 

17 hours ago, nevim said:

To remove the residue on fruits and vegetables add apple cider vinegar to a bowlful of cold water and submerge for 10 mins, then brush fruits/veg gently and rinse well. Obviously not with bananas though...

yeah. right, sometimes we use salt, but I cannot taste the difference, hahah....

7 hours ago, John Cuthber said:

And how did you come to the conclusion that such a process would work?

Is it because vinegar is magical?

A placedo., sometimes you feel  the food is safe and it really becomes safe to your body. But such a process can remove some iinsolvables.

4 minutes ago, chenbeier said:

For this issue there are different analytical machines available, like gas chromatography, UV, IR spectroskopie, nuclear magnetic resonance and others.

To remove the pesticides there is only one way, they shouldnt bring induring growing and harvest of the fruits.

Thanks, really helpful, thanks for the quick reply, 

Hi, everyone, new to this forum. First I should  indicate that I am no scientist nor do some work related to science. I just have great interest in science. And recently, I have a question, how to detect how much pesticide residue is remained in our food,, like banana, and how can we remove the residue?

Thanks!