Protein precipitant–10 g sodium tungstate, 10 g disodium hydrogen phosphate (Na2HPO4) and 9 g sodium chloride are dissolved in 800 ml distilled water. Add 125 ml N HCl to bring the pH to 3.0 (check with narrow range indicator paper). Add 1 g phenol and dilute to 1 litre with distilled water. Keeps indefinitely at 4 °C.