You have more than one calibration data point - Very Good!

You now have a calibration curve using the Stds - Very Good!

Say the 0.04 has area=40000, 0.08 Area=80000 and 0.1 Area=100000, and the Area of your sample analyte has Area of 50000, then the concentration will be 0.05, don't forget the units, in this example, the same as your stds, mg/mL!

Now to confuse you:

It is straightforward using the linear relationship:

y= mx + b, yes, usually the y-axis is for the Detector Response (Height or Area of the response) which is assumed to give a directly proportional relation to the concentration of analyte, when the Correlation Coefficient of the plot is close to unity (0.99-1.0000). The unknown can be matched/fitted on the curve, &/or even better, by just substituting the values of y1=mx1+b, y2=mx=b2, and so on. Concentration in mg/mL in your example is used as the other axis.

Remember that you were asked to use the Area, which I use as well, you might be confused by having two graphs - one is a chromatogram, the other is your calibration curve for Chloroxylenol std.

Don't be confused, this is elementary, you have to get it right!

A reference from

http://en.wikipedia.org/wiki/Calibration_curveseems to have a nice graphing calculator you can use!

http://terpconnect.umd.edu/~toh/models/CalibrationCurve.htmlhttp://terpconnect.umd.edu/~toh/models/CalibrationLinear.GIFDo you see R^2=0.9997? That R^2 is your Correlation Coefficient, and is very good in this image.

Following this, the

Instrument reading is your Area (y-axis) and the Concentration of analyte in Dettol (oops, Chloroxylenol std) is your x-axis (it shouldn't matter too much which is x or y in this example, as long as you are consistent).

I expect you do know how to plot a graph, and use it! That is your Calibration Curve to which you are to fit-your-data of Area of Analyte in sample, and get the unknown concentration.

www.google.com/search?q=calibration+curveAdditional help you may need,

http://en.wikipedia.org/wiki/Parts-per_notation1% solution = 0.01part solute or analyte in the '1-entire solution' => [1/100]*100% = 1%,

therefore, 1mg analyte/{100*(100%)}=0.0001ppm = 0.0001mg/L,

www.onlineconversion.com/forum/forum_1130512020.htmWe can now forget about the above - you may need it to know it for your Multiple Choice Tests, and continue with your Chloroxylenol std solutions of 0.04mg/mL=>40mg/L, 0.08=80mg/L and 0.1 mg/mL=100mg/L,

or 40, 80 & 100ppm Std Solutions, respectively.

Your 1% Chloroxylenol solution is 10,000ppm and much more than your calibration bracket, you need to dilute your Chloroxylenol, say 166.6667 (=500/3) to get your Xchloroxylenol to fit within the calibration bracket of 40, 80, 100 mg/L.

You could read further - Skoog, West, Holler, et al. in your science library/online.

Now go back up to the third line and do it! What is your answer? ____________mg/mL Chloroxylenol in sample.