[MaxFrenzy]

Hey Chemists!

I'm wondering if there are any organic chemists or graduate students in the Chicago (or surrounding area) who I might be able to chat with to bounce some ideas off of. I'd even be thrilled to have someone I could just talk with on the phone/online to discuss some questions and issues.  It would be nice to have someone in the area as eventually I'd like to have someone walk me through some of the processes that I'm interested in performing.  Unfortunately, my college curriculum didn't contain as much science that in hindsight, I wish I had taken. 

Essentially I'm looking into a variety of procedures to work with plant matter (nothing illegal).  Here are some key notes:

* A concentrated extract of the alkaloids in this plant are often used to decrease the ingestion amount of the raw material.  In studies I see them using a variety of solvents in succession, acidifying and basifying the solution at certain points.  I THINK this might be to address the issues of polarity.  There are many alkaloids in the plant and the best I can figure is that they are covering their bases by using polar/non-polar solvents to make a crude extract that is more likely to contain all the alkaloids. 

* There are specific alkaloids in the plant that are desired for extraction/research purposes.  My understanding is that column chromatography has been used in the past (once again, based on studies), to isolate various alkaloids via fractions.  My confusion is in performing that procedure.  There isn't anything out of the ordinary from what I gather (wet slurry, Silicon Dioxide), but I've only seen a CC performed on a basic lab level involving two very different items (beta-carotene and lycopene, resulting in yellow/red layers) and only 3 fractions (yellow, red/yellow mix, and red).  I think they added dye to make things easier visually.  My specific application with its many constituents makes me think this is going to be a nightmare. 

* I'm questioning the water solubility of certain alkaloids.  Water has been used in the past to make a tea with results, but it is not listed as one of the known solvents for this plant.  It would seem that based on this, steam distillation would be a poor candidate as some of the alkaloids may end up in the oil layer and others in the water layer?

* I'd like to consider supercritical CO2 extraction, but it may or may not be appropriate for this as I think a co-solvent is needed to collect the extract and is seemingly often water/alcohol making it a potentially pointless extraction process.

Thanks for your time.  If anyone would be willing to chat, please let me know.       

[MaxFrenzy]

I've received about 50 views or so, but no responses thus far.  Was I too vague or my questions too simple for a forum of this caliber? All I'm really looking for is to have some discussions with someone who has a little experience in this area.  This isn't limited to individuals in Chicago by any means.  I'd be happy to pick the brain of anyone willing to lend a hand.  Is there potentially a more appropriate avenue to make these requests?

Thanks again

[Borek]

It's Easter. And views are not only by humans, but also by bots.

[orgopete]

Well, if you are have some anxiety about the lack of responses, then I suggest you simply take the bull by the horns, as they say. In the old days, I would have suggested looking at the directory of graduate research to see if there might be someone in your area that you would like to consult with. Since we are in the internet age, I'd look over local or not so local schools to see if anyone is doing research that might have the expertise you are seeking.

Then just try contacting them. Call them on the phone (if they'll answer), and explain what you are looking for. You can specify that a graduate student or post-doc would be preferred. You may find that with some food and drink, you can make a connection.

[Doc Oc]

Understand also, that although you promise it wasn't illegal, isolation/extraction of alkaloids from plants has a nefarious sound as many of these are illicit.  It's also hard to do several of the experiments you discussed without access to proper lab space (where would you plan on doing supercritical CO₂ extraction?  You can't just do this with dry ice as far as I know.  How would you do column chromatography unless you have a glass flash column and access to silica and solvents?)

If you would be willing to post more specific answers (ie; what are you trying to isolate and what plant is it in?) that might go a long way towards getting some help from people here, although it still doesn't address the lab space issue.

[Arkcon]

Furthermore, you seem to almost have a general idea of some of the concepts, but you get some of the specifics wrong.  At the same time, you have diverse and advanced concepts in mine.  It would be a lot of work to correct everything, and bring you up to speed, and I worry if you really want all that, since you have a very specific application in mind.  So I'm left worrying where the thread will end up.

[Babcock_Hall]

[Tangential to your main question]  If one separated beta-carotene (yellow-orange) and lycopene (orange-red) on silica, you don't need a dye to visualize them.  These two compounds are chromophores by themselves, and I have separated them on alumina, as opposed to silica.

I don't have any direct experience with alkaloids.  However, if you have protonate an alkaloid under acidic conditions, I expect that it will become much more polar and possibly more difficult to separate on silica.  Do you know whether the compound of interest becomes water soluble upon protonation?

[MaxFrenzy]

Well, if you are have some anxiety about the lack of responses, then I suggest you simply take the bull by the horns, as they say. In the old days, I would have suggested looking at the directory of graduate research to see if there might be someone in your area that you would like to consult with. Since we are in the internet age, I'd look over local or not so local schools to see if anyone is doing research that might have the expertise you are seeking.

Then just try contacting them. Call them on the phone (if they'll answer), and explain what you are looking for. You can specify that a graduate student or post-doc would be preferred. You may find that with some food and drink, you can make a connection.

Thanks for the response, I'll also be looking into this avenue.  The university I attended has a thorough chemistry department and considering I'm alumni, I might be able to make some connections there.

[MaxFrenzy]

Understand also, that although you promise it wasn't illegal, isolation/extraction of alkaloids from plants has a nefarious sound as many of these are illicit.  It's also hard to do several of the experiments you discussed without access to proper lab space (where would you plan on doing supercritical CO₂ extraction?  You can't just do this with dry ice as far as I know.  How would you do column chromatography unless you have a glass flash column and access to silica and solvents?)

If you would be willing to post more specific answers (ie; what are you trying to isolate and what plant is it in?) that might go a long way towards getting some help from people here, although it still doesn't address the lab space issue.

I have access to a lab with a variety of equipment and chemicals available, so from a safety and accessibility standpoint, we'll be using proper equipment, not a kitchen chemist setup   Also, there is funding available to acquire resources that I may be missing.  The reason I'm not mentioning the specific plant out on the board is because I'm trying to protect the client that I'm trying to help out here.  There are people out there selling extracts of these plants, but they are often crude, dirty extracts (as is the case with most work done without the proper tools).  As for super critical CO2.  I haven't abandoned interest in that method for future projects, but this specific application probably won't apply.  There are some cool videos on youtube of an individual who made a supercritical CO2 vessel from machined aluminum and thick acrylic.  He later used it to extract caffeine from green coffee beans.  Neat stuff!

[MaxFrenzy]

[Tangential to your main question]  If one separated beta-carotene (yellow-orange) and lycopene (orange-red) on silica, you don't need a dye to visualize them.  These two compounds are chromophores by themselves, and I have separated them on alumina, as opposed to silica.

I don't have any direct experience with alkaloids.  However, if you have protonate an alkaloid under acidic conditions, I expect that it will become much more polar and possibly more difficult to separate on silica.  Do you know whether the compound of interest becomes water soluble upon protonation?

I believe it does based on what I've read.  When I first posted, I think I misunderstood what was happening.  I later realized that they are doing an acid/base extraction, I think.

Here is a list of the basic steps acquired from a study that already did it:

Plant material extracted into alcohol. 
Alcohol is evaporated leaving crude extract with a bunch of junk + alkaloids.
That extract is dissolved in acetic acid/water mix. 
Acidic mix is washed with pet ether
At this point, I'm assuming a separatory funnel is used and the pet ether layer is discarded.
Remaining acidic solution is then made alkaline to a specific PH.
solution is then extracted with chloroform (once again I think sep. funnel is used and only chloro layer is kept)
chloroform mix is washed with water
water is removed (via drying agent)
chloroform is evaporated leaving all alkaloid salts.

From here, a column chrom. would be used to further isolate/examine.

Thoughts? 

 

[Babcock_Hall]

This sounds like a fairly typical acid-base extraction.  If there are no carboxylic acid groups on your molecule of interest, then it should not be in the form of a salt in chloroform, but rather in the form of a free base.  It seems reasonable in theory, but again, I am not an alkaloid chemist.

[Extracted]

I have access to a lab with a variety of equipment and chemicals available, so from a safety and accessibility standpoint, we'll be using proper equipment, not a kitchen chemist setup  Also, there is funding available to acquire resources that I may be missing.

You mean 'funding' for a paid consultant?  Many of us get paid to perform the service you expect for free.  

 The reason I'm not mentioning the specific plant out on the board is because I'm trying to protect the client that I'm trying to help out here.  There are people out there selling extracts of these plants, but they are often crude, dirty extracts (as is the case with most work done without the proper tools).

This doesn't make sense to me.  If people are already doing it, what's the big secret?  We don't need the plant's name but the name of alkaloid or at least the family of alkaloids is a definite requirement.  I once spent over a year isolating a smallish alkaloid that required extracting in the presence of acid and acetone to make an acetonide.  Purification required multiple flash columns followed ultimately by deprotection under Birch reduction conditions.  It wasn't straightforward at all and certainly required some $$$ to perform on a large scale.  You have a written procedure which is certainly no worse that you will get from us, so why don't you just use the published procedure?

[Borek]

Many of us get paid to perform the service you expect for free.

Oh come on. You don't have to help him, but don't blame someone for trying to save some bucks  

[Doc Oc]

Thanks for the clarification MaxFrenzy.  I will agree that if you need more hands-on help reaching out to grad students at a local university will probably be your best bet.  Offer them a good lunch or a 6-pack of beer, you'd be surprised how far that can go for students.

Alkaloids can be tricky in my opinion; the amines are very polarizable, but they are generally surrounded by so much hydrocarbon that they often slide into the organic layer very easily.  From the procedure you listed, it sounds like the alkaloids of interest are easier to keep in the aqueous layer.

I'm assuming you have some of the pure alkaloid available as a reference standard, right?  If I were you, I'd track its progress by TLC at various phases, including the extractions/washings.  If you find that during the acetic acid/pet ether or neutralized aqueous/chloroform extraction that your compound is staying behind in the wrong layer, try playing around with alternate solvents.  I also think that a lot of the purity issues are going to stem from how good of a flash column you run, so after the chloroform extraction, try to get as clean of a TLC as possible.  If it looks like a bar code, you're going to have to run a tedious/long column to get good pure product (although this is possible, I've done it a couple of times, but don't want to again).  A lot of times, this can be handled with a good extraction/wash procedure though, so that's why I say you want to optimize those conditions before you get to the flash column.

[MaxFrenzy]

I have access to a lab with a variety of equipment and chemicals available, so from a safety and accessibility standpoint, we'll be using proper equipment, not a kitchen chemist setup  Also, there is funding available to acquire resources that I may be missing.

You mean 'funding' for a paid consultant?  Many of us get paid to perform the service you expect for free.  

 The reason I'm not mentioning the specific plant out on the board is because I'm trying to protect the client that I'm trying to help out here.  There are people out there selling extracts of these plants, but they are often crude, dirty extracts (as is the case with most work done without the proper tools).

This doesn't make sense to me.  If people are already doing it, what's the big secret?  We don't need the plant's name but the name of alkaloid or at least the family of alkaloids is a definite requirement.  I once spent over a year isolating a smallish alkaloid that required extracting in the presence of acid and acetone to make an acetonide.  Purification required multiple flash columns followed ultimately by deprotection under Birch reduction conditions.  It wasn't straightforward at all and certainly required some $$$ to perform on a large scale.  You have a written procedure which is certainly no worse that you will get from us, so why don't you just use the published procedure?

Precisely.  There are two aspects of the equation.  Regarding a paid consultant, that is largely the reason I'm seeking an O-chemist in Chicago.  Finding someone who can consult and demonstrate the processes such that we retain a working knowledge is desirable and exactly what we have in mind.  If you happen to be close to Chicago, send me a message.  The second, and equally important aspect, is my education.  Understanding what I'm looking at, why its needed, and what is happening is extremely important so that I can use the knowledge for future applications.  It also largely helps me understand the feasibility of the project, and the reason I say that is because a crude extract is already being made, and I'm seeking to refine the process with a business standpoint in mind.  If the process takes 10 times as long as what they're doing and costs 5x more, it might be a better end result, but a poor business decision.  Sure, I could go enhance my education in the classroom, but this may not be an option.  So really, it is a combination of things.  I'm trying to do as much research as I can to understand what is required.  I don't know how easy it is to procure a chemist, the extent to which they are familiar with doing this, the amount of pay that is typical for a consultant, etc.  So, my thought process is, I better beef up my knowledge and if it comes down to it, I can experiment on my own and see where it leads.  This can be dangerous without proper equipment and knowledge.  I hope that helps give you a better handle on the situation.