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:

Simultaneous determination of glucoraphanin and sulforaphane in Brassica oleracea seeds by high-performance liquid chromatography with evaporative light-scattering detector. In this article, a novel and efficient analysis method is described to simultaneously and quantitatively determine glucoraphanin and its major degradation product sulforaphane by reversed-phase high-performance liquid chromatography (HPLC) coupled with an evaporative light-scattering detector (ELSD). This method was validated according to the regulatory guidelines with respect to precision, accuracy and linearity. The HPLC-ELSD method was successfully used to assess the contents of glucoraphanin and sulforaphane in varieties of Brassica oleracea seeds. The developed analytical method not only avoids the underestimation of total glucoraphanin content, but also provides a reduction in analysis time and good efficiency and sensitivity compared to with conventional HPLC methods.
{"Chemical": ["glucoraphanin", "sulforaphane"]}