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Calibration Curves (Venton)

  • Page ID
    281548
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    The following are hypothetical calibration curves made with a Gas Chromatography instrument (although no GC knowledge is needed for this question).

    CalibrationCurves.png

    Reference: Calibration. Rodríguez Cuesta, Boqué, Vander Heyden, LCGC Europe. 2007 Volume 20, Issue 6, pg 349–356.

    1. Looking at curves A and B (blue and red): which method has the greater sensitivity?  Why?

     

     

     

    1. Looking at Curves A and C (blue and green): Which method has the greater sensitivity?  Why?

     

     

     

    1. Curve C has an offset (i.e. intercept is non-zero).  What types of error could be responsible for that offset? Name a specific example of what could cause that offset.

     

     

     

    1. Calibration curve D is nonlinear.  If you were making and using this calibration curve, what are some potential problems you might encounter and how would you handle them?

     

     

     

    1. Sometimes people do a one point calibration to estimate the concentration.  Would this be a valid approach to approximate curve A?  How about curve C?  Why?

     

     

     

    1. If the standard deviation for the blank is 500, what is the LOD for curve A?

     

     

     

    1. A. For curve A, you run an unknown and your response is 55,000.  What is your amount in your sample?

       

       

      1. For curve A, you run an unknown and your response is 150,000.  What is the amount in your sample?

     

     

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