#  pI = 1.41
#  pH 	   chg
  0.00	  0.07
  0.50	  0.02
  1.00	  0.01
  1.50	 -0.00
  2.00	 -0.01
  2.50	 -0.03
  3.00	 -0.10
  3.50	 -0.26
  4.00	 -0.53
  4.50	 -0.78
  5.00	 -0.92
  5.50	 -0.97
  6.00	 -0.99
  6.50	 -1.00
  7.00	 -1.00
  7.50	 -1.01
  8.00	 -1.02
  8.50	 -1.05
  9.00	 -1.16
  9.50	 -1.39
 10.00	 -1.78
 10.50	 -2.26
 11.00	 -2.84
 11.50	 -3.40
 12.00	 -3.76
 12.50	 -3.92
 13.00	 -3.99
 13.50	 -4.04
 14.00	 -4.13