How clean are your vials and closures? L. Pereira1, T. Edge1, L. Shick2, M. Slade21Thermo Fisher Scientific, Runcorn, UK, 2Thermo Fisher Scientific, Rockwood, USA Results Figure 1 illustrates the UV traces for a blank, a vial with PTFE/silicone closure and a vial + closure with pre-slit, incubated in the inverted position at room temperature.