Recommended latices

The following off-the-shelf standard latices are used for the performance of the Operational Qualification of the Mastersizer 2000, Mastersizer S, Mastersizer X, Mastersizer Micro and Mastersizer Microplus:

(*Only for the Mastersizer X and Mastersizer S with the 1000 mm lens.)

The DVB refers to Divinylbenzene, which identifies the exact form of polystyrene compound used in the particles.

The samples have been chosen carefully to provide highly reproducible results. Because of the wide size range of the MS 2000 product, several measurements are required to ensure that the entire dynamic range has been exercised. Other sizes cannot be substituted, even from the same supplier - this specification applies exclusively to the actual samples named.

Can the same size latex from other suppliers be substituted?
No they can't. An Operational Qualification is supposed to establish that there has been no change in the performance of an instrument since it left the factory. To enable this to be established it is necessary for Malvern Instruments to have thoroughly characterized each batch of the recommended latices in order to establish pass/fail criteria. Without such pass/fail criteria, no basis for an OQ could be established.

What about the same size from Duke?
Duke Scientific Corporation manufactures each product in batches identified by a Manufacture Batch code that has the form 2009-002, for example, indicating batch 002 of the nominal 9µm latex. Each manufactured batch has some differences in particle size from the target size and these are characterized by us prior to the batch use. Batches that have been characterized are identified in the Malvern OQ certificate issued with this procedure. Use of material batches other that those identified will give misleading results due to the unknown batch variation and will therefore not form the basis of valid OQs.

Each manufactured batch of latex is then packaged into lots for sale. To trace individual packaging lots, a Lot No. is indicated on each bottle. Thus full traceability of sample is established by use of the Manufacture Batch No. and Packaging Lot No.

The material has been developed by Duke Scientific Corporation independently of Malvern and is on general sale as a particle size standard.