A recycling method for LST® contaminated during heavy liquid separation in palynological processing

ABSTRACT

An aqueous solution of LST® is one of many heavy liquids used to concentrate palynomorphs. It and aqueous solutions of sodium polytungstate (SPT) are replacing toxic heavy liquids, such as bromoform and zinc bromide, and to a lesser extent zinc chloride, in many palynology laboratories. Both non-toxic heavy liquids can be recycled through filtering and evaporation of water and/or ethanol added to the sample during processing, and commonly are. Both media, and especially LST®, are somewhat reactive with organic matter, and in humic-acid rich samples become contaminated and discoloured. This paper presents the authors' methods for recycling LST® and removing contamination through a combination of filtration through activated charcoal and 0.45 μm nylon membranes. Filtration through Celite® was found to be unnecessary.

KEYWORDS:

• LST®
• heavy liquids
• recycling
• discolouration
• palynological processing

Acknowledgements

Development of this methodology is based upon work supported by the National Science Foundation under Cooperative Agreement No. 1355438 through a Kentucky NSF EPSCoR RSP grant to O'Keefe in support of Black and Gullett.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the United States National Science Foundation Office of Experimental Program to Stimulate Competitive Research [grant number 1355438].

Notes on contributors

Brandon G. Van Ness

DR. BRANDON VAN NESS is an organic chemist in the Department of Biology and Chemistry at Morehead State University. His interests lie in natural product synthesis reactions.

Morgan K. Black

MS. MORGAN BLACK and MR. CLAYTON GULLETT are undergraduate research assistants in the Department of Earth and Space Science at Morehead State University. Both are geology majors and planning to attend graduate school. Ms. Black was the 2015 recipient of the L.R. Wilson Award for best student presentation.

Clayton R. Gullett

MS. MORGAN BLACK and MR. CLAYTON GULLETT are undergraduate research assistants in the Department of Earth and Space Science at Morehead State University. Both are geology majors and planning to attend graduate school. Ms. Black was the 2015 recipient of the L.R. Wilson Award for best student presentation.

Jennifer M.K. O'Keefe

DR. JEN O'KEEFE is a palynologist and organic petrographer in the Department of Earth and Space Science at Morehead State University. Her interests lie in improving processing techniques, melissopalynology, fungal palynology and wetland ecology from the Cretaceous–Neogene.