Extraction phase in the form of a thin layer supported on a fibre made of inert material, such as fused silica, stainless steel, or nickel-titanium alloy.
Source: PAC, 2016, 88, 517. 'Glossary of terms used in extraction (IUPAC Recommendations 2016)' on page 546 (https://doi.org/10.1515/pac-2015-0903)