You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Optimization of ABTS radical cation assay specifically for determination of antioxidant capacity of intracellular extracts of microalgae and cyanobacteria. A renewed interest in antioxidants has arisen in recent years; microalgae and cyanobacteria are potential sources thereof for use as food/feed ingredients. However, improved methods for comprehensive screening of antioxidant capacity specifically in intracellular extracts of marine microorganisms are required - encompassing lipophilic and hydrophilic compounds simultaneously. The original ABTS method was thus improved, and in particular the procedures of cell disruption and storage were optimized. The best solvent found was ethanol/water (1:1, v/v). The reaction to form ABTS(+) in said solvent was essentially complete by eight hours, and this radical cation was stable for at least 6 days; at room temperature, the ABTS(+) solution remained within an allowable analytical range for up to 13 h. Ultra Turrax was the best cell disruption method, and refrigeration was the best preservation method. This improved methodology was validated with four representative strains that respond poorly to cell disruption.
{"Chemical": ["ABTS", "ABTS radical cation", "ABTS(+)", "ethanol"]}