Infos on GC materials / technique for Essential oil analysis

[asgarmoi]

Bonjour a tous,

First of all would you excuse my poor English as i'm french.

I'm working for a company which buy/sell essential oïl as CLOVES or YLANG and which is confronted to product contaminated by pollutants, such as ethanol, glycol and fatty matter.

To avoid too much cost in analysis we are currently spending we thought to invest in equipments to analyse the products we buy, from what we understood we would need to buy a gas chromatography Equipment coupled to base chromatograms :
- A flame ionization detector (FID)
- An injection port Split / Splitless
- A capillary column type CP SIL 8CB (Cat No. 8511), nonpolar, length = 15 m, inner diameter = 0.25 mm film thickness = 0.25 .mu.m.
- A Recorder calculation as "Getek 12x" governed by an appointed as "CHROMA BIO-systems software" for recording and storing calculations. The data would then be processed by an integrator.

Could you please advice me on the equipments/specification to buy and some brands i could go for.

Merci beaucoup pour votre aide.

[GOM]

Bonjour et faites lui un bon accueil !

From my experience essential oils can be diluted by ethanol, glycerol and diethyl phthalate.

You can achieve what you want with GC with an FID but the non polar column that you suggest would not be suitable. You need a polar column for ethanol and glycerol.

What is the fatty matter that you wish to analyse for?

Manual headspace SPME can confirm the presence of diluents

If you approach an instrument manufacturer that you may buy from (e.g. Agilent) they will assist in supplying/advising on the correct columns.

Regards

Ralph

[asgarmoi]

Bonjour GOM

Merci pour ton accueil et tes conseils.

I mean by "fatty matter" in french "matières grasses"

May i ask you by the way you what do you mean by "Manual headspace SPME can confirm the presence of diluents" is it a cheaper way to obtain / identify the presence of this polluants instead of using a GC ?.

For your info we need to perform around 20 tests per day, on 25 days, so around 500 analysis per month.

Here the kind of analysis we would like to perform : "http://hpics.li/24dd8e0"



You suggest me to contact Agilent what i've done today but do you have other company name i can contact to quote this equipemnts so if i understood correctly :

- A gas chromatography Equipment coupled to base chromatograms
- A flame ionization detector (FID)
- An injection port Split / Splitless
- A polar column for ethanol and glycerol
- A Recorder calculation + software

Thanks a lot for your help,

Asgar

[itspip]

Agilent seems to be the gold standard for GC analysis. Shimadzu may be worth looking into as well. For consumables; septa, liners, columns, Restek is pretty common. Any of the manufacturers of the GC should also provide a computer and software.

Good luck!

[asgarmoi]

Merci itspip for the brand

Seems that I will need a bit of luck to find the right equipment and a little more to find it at a right price, on internet i saw new and refurbished and lot of different references, and i don't speak about range of price between 19k€ and 35K€....

It's look like jungle for me

I will look at Shimadzu right now, if you have any other advice do not hesitate and thanks a lot again !!!

[GOM]

Hi Asgar

SPME is a way/technique of introducing the vapour above your sample into the GC.

http://www.sigmaaldrich.com/analytical- ... video.html

If you need to do 20 analyses per day then you really need to consider an autosampler in addition to your GC.

As for the "matières grasses" I am still unsure what that means in terms of what you need for your analysis.

Regards

Ralph

[MSCHemist]

essential oils are distilled so they should contain no nonvolatile materials. Any decent GC-FID should do. For Propylene glycol you will want a wax column. Glycerol I've heard mixed things as to whether it needs to be derivatized or not I believe there are biodiesel columns specifically designed for ethanol, diols, and glycerol.

Fats are almost nonvolatile and need to be transesterfied to do GC or alternatively there are HT nonpolar columns that can elute triglycerides up to 420 deg C or so. However nonpolar columns will make smears out of propylene glycol, glycerol, and to some extent ethanol.

[MSCHemist]

http://www.thermoscientific.com/content ... -14105.pdf

It looks like a biodiesel column would be perfect. It has a high enough temperature to do triglycerides and is polar enough for glycerol, ethanol and PG. Make sure you get the right ferrules and septa to do HT GC. Otherwise even a 5890-FID with and 7673 autosampler is fine and can be had for $5-10k refurbished though I'd go with a 6890.

[asgarmoi]

Bonjour les gars,

So GOM thanks for your idea i asked for an SMPE and autosampler, seems to be a good combination, but the cost is high from a range between 15-25K€ for GC-FID with an SMPE and autosampler we approached 40-50K€ those are the range of prices given by the commercial guy on the phone, I will wait for the first quote and will give you an update.

Regarding your comment MSCHemsit i agree that a decent GC-fid should do the work, especially as we seek only to detect the presence of these pollutants and not the quantities of pollutants present in the sample, the price at the end is going to be the decision criteria.

I will have a look at that biodiesel column THANKS

Maybe if i am very lucky i will find refurbished equipments but from what i understood Shimadzu guy told me he has not a lot of those kinds of stuff in stock.

I keep you all posted if you are interested at least for your advice on the equipments they will quote

[GOM]

To keep the cost down (slightly) you don't need to go down the SPME route with your autosampler - it was just a suggestion for detecting the presence of ethanol, glycerol and propylene glycol - although high boiling point, glycerol and propylene glycol still have a vapour pressure.

I was only trying to think of a way of getting all 3 with one polar column in a single analysis.

The other suggestions using a biodiesel column or other polar columns are very sensible and would only require a direct injection autosampler. However, at the end of the day, you are trying to analyse a very low boiling point and high boiling point compounds in the same run. Ethanol may be tricky on the biodiesel column but may be just possible if your diluent is methanol

If you are not buying second hand equipment then get the instrument manufacturer/supplier to do the development work for you for the analytes that you wish to target. Somebody like Anatune (that I have used before) may do that for you.

Regards

Ralph

[Peter Apps]

Unless you are planning to run so many samples that the machine has to run overnight you do not need an autosampler at all. Chromatography was done with manual injections for decades, and I still do nearly all my injections manually.

Peter

[asgarmoi]

Merci GOM for this very clear explanation really it help me a lot, my idea currently is to go for a GC FID, not a GC SM (too expensive) even if it means at the end less acuracy.

Currently shimadzu is going for a quote based on a GC2010plus-split splitness with FID, let's see with what Agilent is going to come.

Another point i forgot to highlight is that i have to consider also the condition of the country electrical failure, temperature and humidity but there is no miracle solution for that for sure and last but not least cost of the gas I will have to use for the GC.

If i cannot find a viable solution with one of two i will contact Anatune, hey hey i'm french and explain all that stuff in English is going to be a nightmare for me but for sure to have a full packed product study/proposal seems really nice.

Peter Apps, no, no works during night. And agree with you, also because of a matter a price, we will go for manual injection.

[itspip]

For gasses, since you are planing on using a FID which will require Zero Air and Hydrogen, you may want to look into getting gas generators. A small zero air generator will pay for itself within about a year, a Hydrogen generator will take longer to recoup, but if you end up using it as the carrier gas instead of Helium the time to break even on the generator cost would be quicker. Plus, using generators avoids having cylinders in the lab.

No matter how much I ask, none of the generator companies seem to be able to make a Helium gas generator.

[GOM]

Hi

Don't worry about your command of English - it is better than my French


Itspip suggestion of gas generators is good - the comment about a helium generator was a deliberate joke. People used to laugh when I said that it was obtained from helium mines (which it in fact is but it sounds a bit like a jam sandwich mine aka jam butty mine, along with the treacle wells found in Liverpool ). Otherwise the nearest generator is 93 million miles away (150 million kilometres)

You said that you need to perform 20 analyses per day - you will not achieve that with manual injection unless your working day is about 15-20 hours. However, perhaps start off with manual injection as Peter suggested to reduce your initial cost and then later argue for the purchase of an autosampler to improve your productivity

If you are working on your own you need to allow for sample preparation and analysis interpretation and reporting time - this is often overlooked by the powers above.

"country electrical failure, temperature and humidity" should not be a problem in Paris.

I am wondering if the fatty matter part of your analysis may be better achieved by a separate analysis after hydrolysis and conversion to FAMEs.

Although you said that you only need to detect the presence and don't need to get the quantity you will still need to establish your detection levels. From my experience, when somebody asked for only the detection of something they always followed it up by asking how much.

Regards

Ralph

[asgarmoi]

Ciao GOM, itspip,

Yep i followed itsip advise and asked quotation for gas generator also, not for Helium

Regarding the autosampler SHIMADZU thought like you here is by the way the quote i received (around 30k€)

- GC-2010 Plus AF Split-Splitless détecteur FID
- AOC-20i Passeur d’échantillons automatique
- AOC-20s Carrousel 150 échantillons
- Colonne SH-Rtx-Wax 30m x 0,25μm x 0,25mm
- LabSolutions Single GC (Vers 5.XX )
- others spare parts

==> regarding precision it's going to be "around 0,1%"

i forgot to mention i'm taking care of that for a branch based in Indian Ocean, that's why i mentionned "country electrical failure, temperature and humidity" as potential treats, for electrical failure an UPS will do the job for sure for humidity and temperature bit a challenge to tackle.

It's just the beginning i'm waiting for others quote and then will have to do a cost analysis, "wich is the cost for a sample analysis" based on a 4 years amortization plan, to see if it' viable...

GOM on next answer i expect some explanation in French !!!