What compounds can be measured using GC equipment?

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Discussion Overview

The discussion centers on the use of gas chromatography (GC) equipment for measuring organic compounds, specifically focusing on propanol and 2-octanol in mixtures. Participants explore the capabilities of GC with a capillary column and FID detector, as well as the potential use of refractive index (RI) measurements.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • Some participants inquire about the specific compounds that can be measured using GC with a capillary column and FID detector, particularly propanol in a propanol-water mixture.
  • There is mention of the potential simplicity of measuring propanol, but uncertainty exists regarding the compatibility of the setup for this measurement.
  • One participant raises a question about RI experiments, expressing a lack of knowledge about this method.
  • Another participant suggests that GC should be able to measure volatile compounds like propanol and discusses the use of RI for measuring ethanol in water, mentioning the need for standard curves or RI tables.
  • Concerns are raised about measuring 2-octanol, with questions about whether it can be measured directly or if a solvent is required.
  • There are suggestions regarding the use of refractometers and where to find them, although the cost and specific types are uncertain.
  • Participants discuss checking the temperature capabilities of the GC and the boiling point of 2-octanol as factors in measurement.

Areas of Agreement / Disagreement

Participants express uncertainty about the specific capabilities of their GC setups and whether certain measurements can be made directly. There is no consensus on the necessity of RI measurements or the best approach to measuring 2-octanol.

Contextual Notes

Limitations include a lack of clarity on the specific setup compatibility for measuring certain compounds, the dependence on standard curves for accurate measurements, and unresolved questions regarding the use of solvents for 2-octanol.

Shri
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Hi... can anyone help me in using GC equipment for Organic compounds...

i want to know what are the compounds we can measure with GC-capillary column...with FID detector and H2 as a carrier gas...

i want measure propanol concentration present in propanol-water mixture.

please help in this ,... if any material regarding GC you can forward me... it will be help full to me ...

Thanking you
 
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Shri said:
Hi... can anyone help me in using GC equipment for Organic compounds...

i want to know what are the compounds we can measure with GC-capillary column...with FID detector and H2 as a carrier gas...

i want measure propanol concentration present in propanol-water mixture.

please help in this ,... if any material regarding GC you can forward me... it will be help full to me ...

Thanking you

I would imagine that this would be pretty simple however I am not a GC expert and thus do not know of whether any specific aspects of your setup that would be incompatible with obtaining the concentration of the propanol - water mixture.

Have you considered RI experiments?
 
I have a GC- capillary column..with FID detector..

i posted that query to confirm what are the compounds that can be measured using GC.
if we can't able to measure with my GC. what are the required things to measure these components...such as Propanol, ethanol etc...

i don't have idea about "RI" experiments ... what is that ?



Shri...
 
Shri said:
I have a GC- capillary column..with FID detector..

i posted that query to confirm what are the compounds that can be measured using GC.
if we can't able to measure with my GC. what are the required things to measure these components...such as Propanol, ethanol etc...

i don't have idea about "RI" experiments ... what is that ?



Shri...

You should be able to measure it using GC ; or any other volatile compounds. RI is for refractive index , it is commonly used to measure the composition of ethanol in water. When the water / ethanol composition varies each distinct composition has a specific value of refractive index ; although most people prepare a standard curve you may simply consult with a known table - perhaps NIST has RI tables for propanol / water mixtures. Do you have an RI device in the lab?
 
no.. i don't have any RI device in my lab; what is the advantage of having these RI values? ... i have another problem... i have to measure 2-octanol composition using GC .. can i measure directly or i should add any solvent to the 2-octanol component ? ...
 
Shri said:
no.. i don't have any RI device in my lab; what is the advantage of having these RI values? ... i have another problem... i have to measure 2-octanol composition using GC .. can i measure directly or i should add any solvent to the 2-octanol component ? ...

For Propanol it would be faster , with the GC approach you are going to need to setup a standard curve , RI values for Propanol should be tabulated so it is simply a matter of pipetting a small amount of sample onto the surface reader , closing the top , press to read , then wah lah you got your measurement.

For the 2-octanol are you referring to an aqueous solution? For the GC you may want to check the temperature capabilities and then check the BP of 2-octanol.
 
You might be able to find inexpensive (maybe 500 dollars or more?) refractometers; some of them are hand-held. Some of them are designed to read "degrees Brix", but the numbers are convertible to refractive index; you might find something like this in a handbook. Check with laboratory people in the fruit, citrus, or foods industries, and check in scientific supply catalogs to find what you can learn.

(Actually, I do not what kind of prices are for various kinds of refractometers; just do some checking with scientific supply houses).
 
The manufacturer of the capillary column might have a method for you to use. Some of the major manufacturers are just a few mouseclicks away...
 

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