organic acids by ECD detection

[chandresh.soni]

Hi everyone i am new for ECD and presently working on ECD and i have some questions related to ECD.
Does ECD is suitable for determination of Chloro-organic acids in Fluoro-organic acid (Trifluoroacetic acid)at low level (100ppm or less).If yes please Guide me how we can check this. which solvent is suitable for ECD. what precautions is require to operate the ECD.

IF any other suitable technique is possible then please

[tom jupille]

"ECD" is ambiguous. Do you mean "Electrical Conductivity Detection" or "ElectroChemical Detection"?

[chandresh.soni]

Tom,
thanks for start up discussion.
my work is on electron capture detector (ECD) which is used for halogen detection on gas chromatograph.
I am continuous facing the problem to get stable base line.
I have the Varian GC model no. Varian 450.

with regards

[dblux_]

Tom,
thanks for start up discussion.
my work is on electron capture detector (ECD) which is used for halogen detection on gas chromatograph.
I am continuous facing the problem to get stable base line.
I have the Varian GC model no. Varian 450.

with regards

Then you should post in GC not LCD forum.
Yes - ECD is the right choice for determination of chloroorganic acids.
Choose the solvent that ECD is not sensitive to - eg n-pentane.

[MSCHemist]

Yes ECD's can easily get deep into the ppb's for halogenated compounds. 10-100ppm aren't very challenging for such a detector.

The main challenge is carboxylic acids tend to be active compounds and give poor peak shape during GC unless derivatized (esterfied) though there are very polar GC columns available to largely mitigate that. You probably want a free fatty acid column such as this.
http://www.mn-net.com/tabid/10882/langu ... fault.aspx

ECD's respond to compounds with electronegative groups on them such as F's O's N'S Cl's. I'd imagine any hydrocarbon based solvent would give very low signals.

[AICMM]

Remember, ECD response is very heavily dependent on the number of chlorines. One or two, not so sensitive, three or four highly sensitive. You might also consider derivative that enhances like perfluoro which could improve detection limit significantly (and take care of reactivity.)

Finally, it sounds to me like you may have a leak somewhere (or gas contamination) based on your comment about unstable baseline. You should check fittings with a good leak detector and make sure you are not getting any air into your detector.

Best regards,

AICMM

[chandresh.soni]

Thanks , but I feel that my ECD is not working correctly as according to its operating manual to set the contact potential first enter( -760v )and we will observe the signal value of (-127 to -135) which we are getting (-128.3)but after that to get the ECD signal within 5mV of its original value when we adjust the contact potential this signal value is not varying and still we are getting the same (-128mV) while as per manual we require to adjust the contact value +5mV of its original value.
When I discussed it with service engineer he communicates about the detector is working fine but still it is not clear why it is not showing the values which is mentioned in the mannul.
We have the ECD which is installed on Varion GC 450 which is now we are not clear to whom we contact as Varion is purchased by Agilent then its GC business is sold to Bruker and now in india broker is not taking care about GC business.

if any suggestion please provide to operate the ECD.

thanks and regards
chandresh

[dblux_]

...now we are not clear to whom we contact as Varion is purchased by Agilent then its GC business is sold to Bruker and now in india broker is not taking care about GC business.
...

But the people who serviced Varian before aquisition are still alive (I hope ). Try to find them and at least ask for advice.

[Peter Apps]

Bypass all the setup adjustments and run a test mixture - the composition of the test mixture is in the ECD operator's manual. If it passes then all is good.

Peter

[chandresh.soni]

thanks peter, still I am not clear how we can by pass all the set up adjustment as test mixture also requires some kind of parameters and if we are not getting the parameters which is require to check the test mixture how we can run.

chandresh

[Peter Apps]

You seem to be stuck on one particular adjustment of the detector. The column, inlet, carrier flow, oven temperature programme and detector flow and temperature for the ECD test mix are in the operators manual. Set them on the GC, inject test mix. See what you get.

Peter

[chandresh.soni]

yes peter , I will try tis and when I will complete this I will communicate.

thanks for guiding me.

with regards
chandresh

[CE Instruments]

Bruker has sold the majority of its gas chromatography (GC) business, comprising its stand-alone GC systems and GC single-quadrupole (GC-SQ) mass spectrometry systems, to Techcomp Europe, a subsidiary of the Hong Kong-based analytical instrument company Techcomp.

Bruker initially announced its intention to divest these GC systems in July, as part of plans to reduce the product portfolio of its Chemical & Applied Markets (CAM) division, which has been making significant losses over the past four years, and has since found a buyer in Techcomp Europe. In a related move that took place in September, Bruker sold its inductively-coupled plasma mass spectrometry product line and service business, which was also part of its CAM portfolio, to Analytik Jena, a German analytical instrument company.

Included within Techcomp’s purchase of the GC systems is the factory in Freemont, California, where they are manufactured, which Techcomp plans to continue using. As such, it plans to offer positions within Techcomp to certain Bruker employees currently involved with the GC business.

Bruker will continue to produce its GC triple-quadrupole mass spectrometry systems, but will shift manufacture from the Freemont factory to a site in Bremen, Germany. It will also continue to provide service and support for all its GC and GC-SQ products worldwide, although Techcomp has a deferred option to acquire this service business in the next twelve months

[dblux_]

Thank you for in-depth information. Good to know what's going on the market.

[yazmer]

before you turn on the detector, try to get some flow going through it. After you purge the detector, then you can heat it up. You want to bake out your ECD first. Increase the temp of the ECD in steps over period of time. I.e start with 50 and go up 50-100C at a time. When the ECD signal settles - increase again. When you hit 350C or so You'll want to bake it our around 350C for at least 6 hours. Make sure you bake out your column as well as that may be a source of the noise.