Why Teflon?
Teflon vial designs are used for their chemical resistance, mechanical durability and optical properties. Their suitability for liquid scintillation counting depends on the vial geometry, holder and spectrometer configuration.
Teflon vials were initially developed for large volume — at least 7.0 ml or 3.0 ml of benzene. After that, different kinds were developed for measuring small benzene samples down to about 0.3 ml.
New Teflon Vials
Traditional Teflon Vials
Traditional Teflon vial line
Traditional Teflon vials applicable for LS benzene counting, as produced by Perkin Elmer Inc., are 7.0 ml and 3.0 ml. Teflon as material defines counting performances. Working cycle depends on number of parts used and additional materials involved: metal, rubber and Teflon film.
Small 0.8 ml Teflon Vials
Buzinny and Skripkin evaluated 0.8 mL Teflon® vial designs for microvolume radiocarbon dating using a Quantulus 1220 liquid scintillation spectrometer. The reported results characterize the tested vial and holder configurations under the conditions described in the study. In that setup, the authors reported C-14 counting efficiency up to 82%, a background count rate of 0.1 CPM and a figure of merit of 67,240.
Modern Vial Design
The modern vial design avoids screwed connections and uses spline coupling with metal washers. Durability and benzene retention depend on the assembled vial configuration and operating conditions.
Standardized benzene sample volumes: 7.0 ml, 4.5 ml, 3.0 ml, 2.5 ml, 1.5 ml, 1.0 ml
References
- M. Buzinny & V. Skripkin. Newly Designed 0.8-ML Teflon® Vial for Microvolume Radiocarbon Dating. Radiocarbon 37(2), 743–747 (1995). DOI: 10.1017/S0033822200031283.
- VV Skripkin, MG Buzynnyi. Teflon Vials For Precise C-14 in Benzene Measurements. Biological and Chemical Research 4 (Issue 9), 229-233
- Vadim Skripkin, Mykhailo Buzynnyi. Teflon Vials for Precise C-14. LSC-2017 Conference, Copenhagen.