As reported by Thermo, laboratories may try to save money by washing their used autosampler vials and reusing them. However, these products are designed to be disposable and reuse can cause numerous QC issues, such as contaminant peaks, sample loss, and physical deformations on the glass surface. Here a variety of vials are tested for sample loss. Only the new vial showed zero loss for all samples. The others showed variable amounts of loss.
The variable nature of the sample loss can make identifying the cause of the issue problematic. You can avoid all this by simply using new vials each time.