Wyatt Technology’s miniDAWN TriStar™ achieves accurate determination of the molecular weight of Becton Dickinson Medical Polyurethanes

Wyatt Technology has been chosen by Becton Dickinson (BD) Medical to determine the molecular weight of the polyurethanes it manufactures.

Wyatt’s innovative miniDAWN system was coupled to its Optilab refractometer to determine the absolute weight average molecular weight (Mw) and number average molecular weight (Mn) of the BD polyurethanes.

BD Medical is one of the world’s leading suppliers of medical devices. The company has been the leading innovator in injection- and infusion-based drug delivery since 1906 when it built its first manufacturing facility in the U.S. The polyurethanes that BD Medical produces are a proprietary blend intended for use in catheters. Catheters vary in gauge and length as well as in dwell time. The most important parameter when evaluating the efficiency factors of these catheters, including flexibility and tensile strength, is to determine the molecular weight of the polyurethanes. The Mw and Mn values are being used by BD Medical manufacturing departments to access whether their process is running within the specified controls or not. Speed and accuracy of results are of utmost importance.

For this particular application, the mobile phase used was 0.02M LiBr in DMF. This was also used as a diluent. Five dilutions of increasing concentration were prepared in order to obtain the dn/dc of the sample by injecting straight into the Optilab and using Wyatt’s DNDC software. After the dn/dc value was obtained, a sixth dilution was injected through both the miniDAWN and Optilab to obtain the Mw and Mn of the polyurethane. Using Wyatt’s ASTRA software package, the resultant peak was integrated and a report was printed out detailing the Mw, Mn and calculated mass of the sample. The results acquired were highly accurate and within the BD Medical specifications.