In the last installment of the Raw Materials Detectives - The Case of the Fouled Filters - I described a medium filtration problem.
In this investigation, it was determined that PVA was causing the filtration issue and that the problem was related to variation in the degree of hydrolysis seen with the raw PVA.
Subsequent discussions (our data in hand) with the manufacturer eventually convinced them there was a change in the product performance resulting from the hydrolysis effect. It was then determined that an equipment change might be related to this observation.
The manufacturer went back to the old equipment and produced a lot of PVA for SAFC's Raw Material Detectives to test. Lo and behold! The material resulting from the old equipment was more soluble and showed much better filterability. We now have agreements in place to secure only material produced in this manner & thus can make media again with PVA that filters well.
Score ONE for the Raw Material Detectives.
Posted by Bruce Lehr July 21st 2010.