Gas Chromatography (GC)

[Studyinghard]

hm fair enough . VCAA > Insight. although change of study design. Maybe change of answers ? :S

[m@tty]

See VCAA 2002 Short Answer Question 1b.

This is talking about the solvent which the stanozolol was dissolved in. Not the carrier gas (nitrogen).

Are you sure there is a peak for the carrier gas? I would think that it comes through at a steady rate, and justs raises the base line of the chromatogram.. If suddenly all of the carrier gas was gone, what would drive the analytes through?

Q9 , insight 2008. Peak for carrier gas.

They do say that.. Does anyone know if this is actually correct?

I would think that it flows at a steady rate. What is there to push it all out? The role of the carrier gas is to push things through the column, so what pushes this through so that it all comes as a peak?

[stonecold]

Shit, you're right.  In that case, then there mustn't be a peak. 

When I think about it, if the carrier gas produces a peak, then it would always be present on the chormoatgram as one neverending peak.  I've never seen this.  I'm now leaning towards no peak.

[superflya]

if the carrier does produce a peak, that indicates its reacted with something...which u dont want happening.

[Martoman]

I would think that if the carrier produced a peak the question would be nice enough to tell us. Thankfully insight did.

(and on that exam i skimmed that and missed it  )

[m@tty]

Why does it produce a peak when it reacts with something?

EDIT: wait I got it, it produces a new compound which has different attraction to the stationary phase => different retention time => separate peak.

[Martoman]

Just thinking about GC in general...............

Polarity still has a play in this as that determines how much it will dissolve yes?

yet its more dependent on the molar mass?

[VCE123456789]

The peak is due to the solvent not beacuse of the carrier gas