title: Particle concentration measurement of virus samples using electrospray differential mobility analysis and quantitative amino acid analysis.
abstract: Virus reference materials are needed to develop and calibrate detection devices and instruments. We used electrospray differential mobility analysis (ES-DMA) and quantitative amino acid analysis (AAA) to determine the particle concentration of three small model viruses (bacteriophages MS2, PP7, and phiX174). The biological activity, purity, and aggregation of the virus samples were measured using plaque assays, denaturing gel electrophoresis, and size-exclusion chromatography. ES-DMA was developed to count the virus particles using gold nanoparticles as internal standards. ES-DMA additionally provides quantitative measurement of the size and extent of aggregation in the virus samples. Quantitative AAA was also used to determine the mass of the viral proteins in the pure virus samples. The samples were hydrolyzed and the masses of the well-recovered amino acids were used to calculate the equivalent concentration of viral particles in the samples. The concentration of the virus samples determined by ES-DMA was in good agreement with the concentration predicted by AAA for these purified samples. The advantages and limitations of ES-DMA and AAA to characterize virus reference materials are discussed.
authors: Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. Kenneth.Cole@nist.gov
authors: Kenneth D
authors: KD
authors: Cole
authors: Leonard F
authors: LF
authors: Pease
authors: De-Hao
authors: DH
authors: Tsai
authors: Tania
authors: T
authors: Singh
authors: Scott
authors: S
authors: Lute
authors: Kurt A
authors: KA
authors: Brorson
authors: Lili
authors: L
authors: Wang
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D001435:Bacteriophages / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D010316:Particle Size
chemical_list: D000596:Amino Acids