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    How do you determine an instrument's (hplc or gc) detection sensitivity? How do you determine the detector's limit of detection (LOD) and limit of quantitation (LOQ)?

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    https://brainmass.com/chemistry/experimental-design-and-methods-in-chemistry/chromatography-578521

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    Detection sensitivity
    Q. How to determine an instrument's (hplc or gc) detection sensitivity? And how to determine detector's limit of detection (LOD) and limit of quantitation (LOQ)?

    A. Maximum sensitivity means we will be able to detect smaller changes in concentration.
    GC's are equipped with flame ionization detectors (FID), Mass Spectrometry (MS) detectors or thermal conductivity detectors (TCD). FID's provide the best sensitivity and linearity for most volatile and semi volatile compounds. Detection limits for most compounds using the FID are typically in the range of 1-5 micrograms per gram of sample (1-5 ppm).

    Limit of Blank (LoB), Limit of Detection (LoD), and Limit of Quantitation (LoQ):

    LoB is the highest apparent analyte concentration expected to be found when replicates of a blank sample containing no analyte are tested.
    LoB = meanblank + 1.645(SDblank)

    LoD is the lowest analyte concentration likely to be reliably distinguished from the LoB and at which detection is feasible. LoD is determined by utilising both the measured LoB and test replicates of a sample known to contain a low concentration of analyte.
    LoD = LoB + 1.645(SD low concentration sample)

    LoQ is the lowest concentration at which the analyte can not only be reliably detected but at which some predefined goals for bias and imprecision are met. The LoQ may be equivalent to the LoD or it could be at a much higher concentration.

    References:
    1) http://www.atomsandnumbers.com/2013/numbers-of-atoms-finding-the-smallest-traces-with-gas-chromatography/
    2) http://www.galbraith.com/chromatography.htm
    3) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2556583/

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

    © BrainMass Inc. brainmass.com December 24, 2021, 11:32 pm ad1c9bdddf>
    https://brainmass.com/chemistry/experimental-design-and-methods-in-chemistry/chromatography-578521

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