title: Quantitative determination of the polypeptide motilin in rat plasma by externally calibrated liquid chromatography/electrospray ionization mass spectrometry.
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 microL. The LC system included a C(18) column with a 300 A 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.
authors.affiliation: College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Delinsky
authors.forename: Kimberly T
authors.initials: KT
authors.lastname: Hill
authors.forename: Catherine A
authors.initials: CA
authors.lastname: White
authors.forename: Michael G
authors.initials: MG
authors.lastname: Bartlett
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005765:Gastrointestinal Agents / Q000097:blood*; D008297:Male; D009037:Motilin / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013552:Swine
chemical_list: D005765:Gastrointestinal Agents; D009037:Motilin