SOURCES SOUGHT
66 -- RFI Static Light Scattering
- Notice Date
- 5/14/2012
- Notice Type
- Sources Sought
- NAICS
- 334516
— Analytical Laboratory Instrument Manufacturing
- Contracting Office
- ACC-APG - Natick (SPS), ATTN: AMSRD-ACC-N, Natick Contracting Division (R and BaseOPS), Building 1, Kansas Street, Natick, MA 01760-5011
- ZIP Code
- 01760-5011
- Solicitation Number
- W911QY-WARSTAR002
- Response Due
- 5/22/2012
- Archive Date
- 7/21/2012
- Point of Contact
- Steven Streeter, 508-233-6180
- E-Mail Address
-
ACC-APG - Natick (SPS)
(steven.e.streeter4.civ@mail.mil)
- Small Business Set-Aside
- N/A
- Description
- The U.S. Army Research, Development, and Engineering Center, Soldier Systems Center, Natick, MA, Warfighter Science, Technology and Applied Research Directorate has a need to identify potential source capable of supplying the following: Description of Instrument: Instruments: 3 to 18 angle static light scattering instrument for the measurement of absolute molecular weight, size, and conformation of macromolecules and particles in solution. Options may or may not include: (1) allowing both multiple-angle dynamic light scattering and static light scattering experiments; (2) instruments having photomultiplier tube and standard cross-correlator detectors; (3) instrument operation at 632.8, 514.5, and 488.0 nm laser lines. General Description of Requirement: Multi-Angle Light Scattering (MALS) Instrumentation [also known as Static Light Scattering (SLS), Classical Light Scattering or Differential Light Scattering]. Static light scattering is a technique in physical chemistry that measures the intensity of the scattered light to obtain the average molecular weight of a macromolecule like a polymer or a protein. For static light scattering experiments, a high intensity monochromatic light, usually a laser, is launched in a solution containing the macromolecules. One or many detectors are used to measure the scattering intensity at one or many angles. In order to measure the weight average molecular weight directly, without calibration, from the light scattering intensity, the laser intensity, the quantum efficiency of the detector and the full scattering volume and solid angle of the detector needs to be known. Since this is impractical, all commercial instruments are calibrated using a strong, known scatterer like toluene since the Rayleigh Ratio of toluene and a few other solvents were measured using an absolute light scattering instrument. Data Analyses: (1) Guinier plot. The scattered intensity can be plotted as a function of the angle to give information on the Rg which can simply be calculated using the Guinier approximation as follows: where ln( R( )) = lnP( ) also known as the form factor with q = 4 n0sin( /2)/. Hence a plot of the corrected Rayleigh ratio, R( ) vs sin2( /2) or q2 will yield a slope Rg2/3. However, this approximation is only true for qRg < 1. Note that for a Guinier plot, the value of dn/dc and the concentration is not needed. (2) Kratky plot. The Kratky plot is typically used to analyze the conformation of proteins, but can be used to analyze the random walk model of polymers. A Kratky plot can be made by plotting sin2( /2) R( ) vs sin( /2) or q2 R( ) vs q. (3) Debye plot. Theoretical Zimm Plot showing the double extrapolation to Mw, the bright green pointThis method is used to derive the molecular mass and 2nd virial coefficient, A2, of the polymer or polymer complex system. The difference to the Zimm plot is that the experiments are performed using a single angle. Since only one angle is used (typically 90 ), the Rg cannot be determined as can be seen from the following equation: (4) Zimm plot. For polymers and polymer complexes which are of a monodisperse nature () as determined by dynamic light scattering, a Zimm plot is a conventional means of deriving the parameters such as Rg, molecular mass Mw and the second virial coefficient A2. One must note that if the material constant K defined above is not implemented, a Zimm plot will only yield Rg. Hence implementing K will yield the following equation: Experiments are performed at several angles and at least 4 concentrations. Performing a Zimm analysis on a single concentration is known as a partial Zimm analysis and is only valid for dilute solutions of strong point scatterers. The partial Zimm however, does not yield the second virial coefficient, due to the absence of the variable concentration of the sample. Source: http://en.wikipedia.org/wiki/Static_light_scattering Marketplace: Several commercial companies offer equipment with a variety of options. Point of Contact (P.O.C.): Interested parties may identify their interest and capability to respond to this requirement to the U.S. Army RDECOM Contracting Center, Natick Contracting Division via e-mail to: Stephanie.A.Marcott.Civ@Mail.Mil mil no later than 5:00 PM (EST) on May 22, 2012. Stephanie A. Marcott, Research Chemist Natick Soldier Research Development and Engineering Center (AMSRD-RDNS-WSC-M) WarSTAR - Molecular Science and Engineering Team Phone: 508-233-6998 Fax: 508-233-5363 Email: Stephanie.A.Marcott.Civ@Mail.Mil
- Web Link
-
FBO.gov Permalink
(https://www.fbo.gov/notices/b4cc866036049eec854a245c19a6e55f)
- Place of Performance
- Address: ACC-APG - Natick (SPS) ATTN: AMSRD-ACC-N, Natick Contracting Division (R and BaseOPS), Building 1, Kansas Street Natick MA
- Zip Code: 01760-5011
- Zip Code: 01760-5011
- Record
- SN02747849-W 20120516/120515001016-b4cc866036049eec854a245c19a6e55f (fbodaily.com)
- Source
-
FedBizOpps Link to This Notice
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