If you need a Certificate of Assurance for your refractive index liquids as part of your quality management procedures then please just add one with your order under certificates in our shop.

The suspect bottle is well shaken and three test slides made up without asbestos present. If asbestos fibres are observed using dispersion staining, crossed polars or first order red plate examination, then the liquid is disposed of. We recommend that the liquids are checked for contamination on a monthly basis by performing this test using [...]

Why is my refractive index liquid getting darker in colour? It is normal for these liquids to get darker as they age which may cause them to go from a light yellow to a dark yellow-purple, however the index will be fine.