Remove special charactors T-sql

Hi I found the function i have to remove the special characters in the Table. But After i used that function all sentence with out spaces.
Original :  select dbo.RemoveSpecialChars('Test-Master," ®+ BAP Reagent')
Results after use function below - TestMasterBAPReagent
Expected Results Test-Master  BAP Reagent

 ALTER function [dbo].[RemoveSpecialChars] (@s varchar(256)) returns varchar(4000)
       with schemabinding
    begin
       if @s is null
          return null
       declare @s2 varchar(256)
       set @s2 = ''
       declare @l int
       set @l = len(@s)
       declare @p int
       set @p = 1
       while @p <= @l begin
          declare @c int
          set @c = ascii(substring(@s, @p, 1))
          if @c between 48 and 57 or @c between 65 and 90 or @c between 97 and 122
             set @s2 = @s2 + char(@c) 
          set @p = @p + 1
          end
       if len(@s2) = 0
          return null
       return @s2
       end

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Any idea?