if you use Power Query in the User Interface the em dash is automatically identified in this Mcode
Code:
let
Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Split Column by Delimiter" = Table.SplitColumn(Source, "Column1", Splitter.SplitTextByDelimiter("—", QuoteStyle.Csv), {"Column1.1", "Column1.2"})
in
#"Split Column by Delimiter"