Calibration Curve

[rayray17]

Hi,
This may seem like a stupid question but when creating a calibration curve for Chromo or Spectrometry, if they dont give the point's (100,230) (200,540) (300,820) should i start my graph from the origin (0,0)

Thanks,
Ray

[Somye]

I wouldn't, because I don't technically think you're allowed to extrapolate graphs, (otherwise why would you have to make a soln fit within the bounds of the curve)

That said, someone else may be able to offer a better insight

[Truck]

Never extrapolate anything, so always plot the graph between the points you're given. Also remember, a solution with 0 concentration of the substance your analysing (i.e.) a solvent may still read some absorbance, so you might be incorrect starting it at (0,0).

[Tonychet2]

correct me if im wrong but, you ARE allowed to extrapolate points before your given points, but not after so e.g

if your given between 100 - 500 u can extrapolate to 0 but not > 500


edit: nvm im sure this is pretty wrong

[amilss]

Feel free to correct ME if im wrong, but my teacher told us we can't extrapolate below our lowest point, but we can continue it above our highest point

Im not sure either way:/ so im just gunna confine any calibration graphs to the points given

[Shenz0r]

I'm pretty sure you can't extrapolate past the points you've been given, whether it be above or below

[Phy124]

Last year my teacher, an assessor, deducted marks on a SAC for extrapolating graphs below the lowest given point (down to 0). I can't recall about going above though, sorry. I probably wouldn't go above either, though.