C#

hello everyone, I'm a young developer c#, I'm using dapper for data manipulation, I have a database on which making a particular query I get 100K + 18 rows that will have to be exported to excel . The problem lies in the fact that, to get the results, it takes almost 12 minutes....to have array_channel_list[i],Can you speed it up in some way ?thank you very much! (sorry for my bad english)

<pre> 
List<string> query = new List<string>();
                    List<EntityFramework.Channels>[] array_channel_list = new List<EntityFramework.Channels>[dim];

   using (var conn = new SqlConnection(connection))
         {
         for (int i = 0; i < dim; i++)
             {
             query.Add("SELECT ID, matricola, disegno, descrizione, nodeid, result, coppia, angolo, prgnr, prgname, date, NomeFile, lastcmd, laststeprow, laststepcolumn, qualitycode, rootobj_ID FROM dbo.Channels where rootobj_ID IN (" + string.Join(",", array_id[i]) + ") ORDER BY ID");

               try
                  {
                  array_channel_list[i] = conn.Query<EntityFramework.Channels>(query[i], commandTimeout: queryTimeoutInSeconds,buffered:false).ToList();

                   }
                   catch (SqlException error)
                        {
                        Console.WriteLine("Errore: " + error.ToString());
                        }

                 }

             }