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:

Fast determination of sulfonamides from egg samples using magnetic multiwalled carbon nanotubes as adsorbents followed by liquid chromatography-tandem mass spectrometry. A simple and effective method based on magnetic separation has been developed for the extraction of sulfonamides (SAs) from egg samples using magnetic multiwalled carbon nanotubes (MMWCNTs) as an adsorbent. The MMWCNTs were simply prepared by depositing Fe3O4 onto MWCNTs that had been previously oxidised. The extraction procedure was carried out in a single step by blending and subsequently stirring the mixture of MMWCNTs and aqueous egg samples. The SAs were first extracted as described above, adsorbed onto the MMWCNTs directly and finally analysed by liquid chromatography-tandem mass spectrometry. The limits of detection obtained are in the range of 1.4-2.8ngg(-1). The proposed method was successfully applied in determining SAs in the eggs obtained from laying hens fed with SA standards, and compared to eggs purchased from local markets. The results demonstrate that SAs were detectable in the incurred egg samples.
{"Chemical": ["carbon", "sulfonamides", "Fe3O4", "SAs"]}