How Do You Get The Concentration Of A Solution That Has Greater Concentration Than The Highest Standard?
April 17th, 2009
I did an experiment where we measured the absorbance of known concentrations of a solution. Then we measured the absorbance of an unknown and got its concentration by comparing to the others. Would this process be any different if we knew that the unknown concentration was higher than the highest known concentration we had?
Entry Filed under: concentration of the solution
1 Comment Add your own
1. Erebos | April 17th, 2009 at 6:42 am
practically, yes. i assume you did a whole bunch of standards and plotted their concentration against absorbance. then you measured the absorbance of the unknown and interpolated the concentration, right? The problem with finding a concentration higher than the highest standard you did, is that extrapolating the graph is not a practical thing to you. though you’d expect absorbance to increase linearly as you increase concentration, it actually doesn’t. if you measure higher standards, you’ll notice that the curve will start to plateau, and it’s no longer linear. There’s a finite range where the graph is linear and you can infer concentrations, outside that range, you can’t do so. So, so can’t simply assume that the part off the graph is linear and extrapolate absorbances higher than the highest standard you ran.
Leave a Comment
You must be logged in to post a comment.
Trackback this post | Subscribe to the comments via RSS Feed