title: Accurate weighing and dilution-assisted plasma microsampling (AWADA-PM): an easy-to-implement and rugged strategy.
abstract: BACKGROUND
  Liquid microsampling can realize ethical benefits through reduced animal usage. It inherently deals with a minute amount of sample; for example, <30 µl of plasma, which is generally insufficient for multiple analyses.
  
  
  RESULTS
  We report accurate weighing and dilution-assisted plasma microsampling (AWADA-PM) that substantially increases sample sizes (e.g., by tenfold). Plasma samples are harvested from blood samples (~70 µl) in capillaries. The plasma samples are weighed with a calibrated balance. The weights are converted to volumes using a standard plasma density of 1.025 g/cm(3). Diluent is added with a calibrated pipette to the harvested plasma to achieve a tenfold dilution.
  
  
  CONCLUSIONS
  The proof-of-concept for AWADA-PM was successfully demonstrated for the quantitation of acetaminophen in rat plasma (K2EDTA) using liquid chromatography-tandem mass spectrometry employing water and blank rat plasma as diluents. The results clearly demonstrate that the AWADA-PM strategy is an easy-to-implement and reliable microsampling technology that has potential for full regulatory compliance.
authors.affiliation: Covance Laboratories, Inc., Bioanalytical Chemistry, 3301 Kinsman Boulevard, Madison, WI 53704, USA.
authors.forename: Fumin
authors.initials: F
authors.lastname: Li
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Fast
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Ploch
mesh_terms: D000818:Animals; D001800:Blood Specimen Collection / Q000295:instrumentation / Q000379:methods*; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D006400:Hematocrit / Q000379:methods*; D010949:Plasma; D051381:Rats; D053719:Tandem Mass Spectrometry / Q000379:methods*