Instrument

NOTICE OF INTENT TO ISSUE A PURCHASE ORDER. The Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health (NIOSH), Cincinnati, Ohio, hereby announces its intent to issue a purchase order to Malvern Instruments, Inc. for Zetasizer Nano-ZS for the measurement of size, molecular weight and zeta potential of dispersed particles and molecules in solution. Includes 4mW 633 He-Ne laser. Temperature range 2deg.C minimum 90deg.C maximum (70deg.C maximum with disposable DTS1060 cell). Size range: 0.6nm to 6microns. Size range for zeta potential 5nm to 10microns. Concentration range for size measurement 0.1ppm to 40wt% maximum. Molecular weight range: 1X10E3 to 2x10E7Da. Compatible with Windows 2000 and XP operating systems. Unique characteristics of the item: Zetasizer Nano-ZS has fast measurement of zeta potential, particle size distribution, and molecular weight; measures concentrated samples; provides small-volume, disposable cells/electrodes to reduce contamination; provides efficient and user friendly software package; and utilizes phase analysis for zeta potential measurements, which offers 1000 times more sensitivity compared to frequency changes. The instrument also has available patented, disposable zeta potential cells that eliminate sample cross-contamination and eliminate the need for washing/cleaning zeta potential cells/electrodes. This cell is a flow-through design also capable of connecting with the Malvern MPT-2 autotitrator for determining the relationship between zeta potential and pH (or any other titratable function). The instrument also includes the following: 1. The backscatter optics. At the 173 backscatter angle for sizing, the volume observed is about 8 times the volume observed with 90degree scattering optics, all other things being equal. This gives 8 times the detected count rate. This improvement relates directly to improved sensitivity. 2. The fiber detection system. The fiber detection optics ensure that the Signal/Background ratio or more correctly, the y-Intercept of the correlogram, is not degraded at these high detection volumes as it would with 'classical' optics. Increasing the count rate (using a higher power laser, for instance) while simultaneously reducing the intercept is of little value. 3. The high efficiency detector. A highly efficiency avalanche photodiode detector (APD), specially selected for dynamic light scattering applications is used, giving typically ten to fifteen times the efficiency of a photomultiplier, and hence ten to fifteen times the sensitivity. There are currently no other systems that use a backscatter configuration that have a high efficiency APD. 4. The optics. The design of the optics means that losses in the light collected are minimized. 5. The suppression of 'noise'. Sensitivity is not all about count rate, for example heterodyne backscatter systems have a very high count rate but low sensitivity. This is because most of the count rate in a heterodyne system is a reference signal that does not contribute to the data. What is as important as the count rate is the suppression of noise or flare, so that all the photons detected contribute to the data. There are a number of ways this is done in the ZETASIZER NANO SERIES: a) suppression of reflections in the optics set up, including the tilting of the sample cell b) optimizing the Signal/Noise automatically, by moving the cell to the optimum position to maximize the Intercept and the count rate c) Using symmetrical normalization in the correlator. This compensates for the statistical fluctuations between channels as the count rate varies, and gives a more reliable value for each channel. This achieves the same data quality in a shorter time, or conversely better data over an equivalent time d) Stabilization of the optics and electronics, so that count rates only 50% in excess of the count rate obtained from the dispersant are high enough to enable a measurement to be made and e) Use of a He-Ne laser gives an exceptionally low noise stable source, with an excellent polarization ratio and mode stability. 6. The high concentration capability. The backscatter configuration allows the instrument to adjust the depth of penetration into the sample cell automatically thus reducing the scattering volume for high concentration samples thus reducing or eliminating number fluctuations and/or multiple scattering effects. This improves the result accuracy and precision dramatically. 7. The ability to attach the instrument to an existing size exclusion chromatography (SEC) system to get real-time measurement of absolute size as macromolecules elute from a column. With optional flow-mode accessory (Part # ZEN9064), flow mode operation is possible with flow rates up to 1mL/min and allows connection of 1 or 2 external detectors and remote measurement start trigger signal for the collection and overlay of Intensity, hydrodynamic diameter and molecular weight estimate data with your existing signal(s) from UV and/or RI detectors. This method provides reliable molecular weight estimates in real-time without column calibration. The Zetasizer Nano ZS is able to measure static, dynamic, Absolute Size Exclusion Chromatography (ASEC) and electrophoretic light scattering measurements for determining size, distribution, molecular weight and zeta potential in the same instrument with the same size and concentration range. The Zetasizer Nano-ZS is unique in its use of backscatter optics, fiber detection technology, the use of an APD detector and an automated cell positioning mechanism. This gives the system the high sensitivity and also the widest range of applications. This project is supported by justification for other than full and open competition to Malvern Instruments, Inc. under authority of 41 U.S.C.253(c)(1). Responsible sources that believe they possess the capabilities identified above can submit to the Contracting Officer, within 15 days from the posting date of this notice, their written item description/item characteristics and pricing information in the format they choose, not to exceed 10 pages. Please forward the item description and pricing information to Jennifer Bayer, Purchasing Agent, Reference #000HCCGD-2008-59611, CDC/NIOSH, 4676 Columbia Parkway, Mail Stop C-4, Cincinnati, OH 45226. All vendors must be registered in the Central Contractor Registry (CCR) prior to an award of a federal contract. The website is: www.ccr.gov. The Government will review any/all item descriptions and pricing information submitted and determine if other qualified sources do exist that could provide this requirement. Information received in response will be used solely for the purpose of determining whether to conduct a competitive procurement. If no affirmative responses are received within 15 days, in accordance with FAR 13.106-1(b)(1), negotiations will be conducted with Malvern Instruments, Inc. and a purchase order will be issued without any additional notices being posted.