Ways of supplying free radicals to a solution?

[science726]

Can everyone please add their thoughts on how to supply free radicals to an artificial environment. The experiment is the effects of antioxidants and free radicals on seed germination. I had 10 mL of hydrogen peroxide (free radical), the antioxidant, and thirty radish seeds in a petri dish, and observed the amount of seeds that germinated. Would there be an alternate way to supplying a free radical for this experiment? Doesn't matter if I have to change the environment (petri dish) to something else, as long as I get the free radical. I was thinking possibly electrolysis to obtain the oxygen free radical, but how would I maintain the oxygen free radical in the petri dish with the antioxidant (liquid form) and radish seeds?

 

Thanks everyone.

[hermanntrude]

the phrase free radical covers a wide range of substances. Technically nitrogen monoxide is a free radical but it's stable at room temperatures. other free radicals are so reactive it's hard to know they ever existed because they react so fast.

 

Ideally you need to find out what type of free radical you're investigating, because if you put one type in you'll get one result and if you put another you'll get another.

[Mr Skeptic]

Just so you know, plants and animals have a special enzyme dedicated to breaking down hydrogen peroxide. So my guess is that if you use that as your free radical, you will not notice much difference.

[science726]

I was planning on using the oxygen free radical, but how would I make it present so that it would affect the seeds and solution?

[hermanntrude]

you can make oxygen free radicals from oxygen gas if you shine UV light on it, i think. eventually it forms ozone

[CharonY]

There are a number of possibilities. Paraquat is often used to generate oxygen radicals in tissue tests. You should just keep in mind that different radicals affect tissue differently and are protected by different mechanisms (with major players being SOD and catalase).

 

So my guess is that if you use that as your free radical, you will not notice much difference.

As a side note, every aerobic organism possesses mechanisms to defend against oxidative stress (that is why they can be aerobic to begin with). But it does not mean that it oxidative stress does not influence the organisms. It only means that they can survive a higher amount of it.

[John Cuthber]

You don't need to do anything to oxygen to make a free radical. The triplet ground state has unpaired electrons, is paramagnetic, and reacts readily with other radicals.

It already is a free radical.

You can buy free radicals from chemical suppliers- galvinoxyl is one of the better known ones.

https://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=G307%7CALDRICH&N5=SEARCH_CONCAT_PNO%7CBRAND_KEY&F=SPEC〈=en_US

[science726]

Thanks for the replies.

 

Would paraquat be able to be used in this situation though, where tissue isn't used? I'm using water, the free radical, an antioxidant, and the seeds.

 

John, so I can use any free radicals such as galvinoxyl and it will create oxygen free radicals? Will the free radicals stay in the solution so they'll effect the seeds?

 

Thanks for all the help.