Explore BrainMass
Share

Explore BrainMass

    Analytical Chemistry - Fluorometric method

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    (See attached file for full problem description)

    ---
    23. In developing a fluorometric method, you measure a standard Analyte at 3.00 ppm (w/w) in the matrix at three different pH values: 2,5,8. You then compare the effects of internal calibration by adding 2.00ppm Analyte to your matrix vs external calibration via pure standards and obtain the following data

    pH= 2 Slope=2607
    Intercept = 3466
    Measured signal for 3.00ppm standard =12781
    Signal after 2.00ppm spike =15611

    pH= 5 Slope=2651
    Intercept = 1232
    Measured signal for 3.00ppm standard =9215
    Signal after 2.00ppm spike =14503

    pH= 8 Slope=434
    Intercept = 1156
    Measured signal for 3.00ppm standard =2205
    Signal after 2.00ppm spike =2920
    A) Derive the equations needed to solve the concentration from i) the straight line equation, y=mx+b and the measured signal 'S' for the external and ii) the data points (0,Ssignal), and (Cspike, Ssignal+spike).
    B) Determine which pH condition has (I) little influence from the matrix, (II) decreased signal because of the matrix, and (III) false enhancement of signal from the matrix. Be sure to subtract the background signal!
    ---

    © BrainMass Inc. brainmass.com October 9, 2019, 5:12 pm ad1c9bdddf
    https://brainmass.com/chemistry/experimental-design-and-methods-in-chemistry/analytical-chemistry-fluorometric-method-50668

    Attachments

    Solution Preview

    (A) At PH = 2
    m = 2607, b=3466
    y=mx+b
    y= 2607x + 3466
    y - 3466 = 2607x
    x = (y - 3466)/2607

    At PH = 5
    m = 2651, ...

    Solution Summary

    A question involving the fluorometric method and the measure of a standard Analyte.

    $2.19