Solution D
0.5% (w/v) sodium lauryl sarcosinate
To prepare denaturing solution: Dissolve 250 g of guanidinium thiocyanate in 293 ml of H2O, 17.6 ml of 0.75 M sodium citrate (pH 7.0), and 26.4 ml of 10% (w/v) sodium lauryl sarcosinate. Add a magnetic bar and stir the solution on a combination heater-stirrer at 65°C until all ingredients are dissolved. Store Solution D at room temperature, and add 0.36 ml of 14.4 M stock ß-mercaptoethanol per 50 ml of Solution D just before use. Solution D may be stored for months at room temperature but is sensitive to light. Note that guanidinium will precipitate at low temperatures.
