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Quantitative determination of the polypeptide motilin in rat plasma by externally calibrated liquid chromatography/electrospray ionization mass spectrometry

Authors

  • David C. Delinsky,

    1. College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, USA
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  • Kimberly T. Hill,

    1. College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, USA
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  • Catherine A. White,

    1. College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, USA
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  • Michael G. Bartlett

    Corresponding author
    1. College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, USA
    • College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, USA.
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Abstract

We present a method for the quantitation of motilin from rat plasma by protein precipitation and liquid chromatography/mass spectrometry (LC/MS). Using external calibration, the method was linear over the concentration range 10–1000 ng/mL with an initial sample volume of 150 μL. The LC system included a C18 column with a 300 Å pore size. A linear gradient was used with a mobile phase consisting of water and acetonitrile, each with 0.2% acetic acid and 0.02% trifluoroacetic acid. Motilin was detected with the mass spectrometer in positive ion mode monitoring the 4+ charge state at m/z 675.5. The approximated limit of detection was less than 1 ng/mL and the lower limit of quantitation (LLOQ) was 10 ng/mL. The method showed a high degree of precision and accuracy both within and between runs at five validation points, including the LLOQ. Copyright © 2004 John Wiley & Sons, Ltd.

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