Sonication improves the efficiency, efficacy and safety of phytolith extraction

Phytolith analysis is increasingly used in archaeological and paleoecological research, yet the methods used to extract phytoliths from some types of sediments are still not completely satisfactory. This paper reports on the effect of adding sonication to protocols frequently used for phytolith extraction. We compare two common methods of phytolith extraction, both with and without part of the process being carried out in an ultrasound bath. Results show that sonication permits the destruction of soil micro aggregates and, in doing so, improves the removal of both soil organic matter and clay. Adding sonication to commonly used protocols for phytolith extraction is inexpensive and reduces the processing time and the need to use dangerous products, even with the samples that are most difficult to treat. Sonication increases the purity of the extracted phytoliths as well as augmenting the quantity of recovered phytoliths.