Sigma-Aldrich L-CYSTEINE FOR BIOCHEMISTRY 1 KG

Assay (perchloric acid titration, calculated on dried substance): ≥ 99.0
Identity (IR-spectrum): passes test
Appearance: colorless to white, needle-shaped crystals
Appearance of solution (100 g/l, hydrochloric acid  2 mol/l): clear and colorless
Spec. rotation (α 20/D, 80 g/l, hydrochloric acid 1 mol/l, calc.on dried substance): +8.3 to +9.5
pH (25 g/l; CO₂-free water): 4.5 - 5.5
Chloride (Cl): ≤ 0.04 %
Sulfate (SO₄): ≤ 0.03 %
Heavy metals (as Pb): ≤ 0.001 %
As (Arsenic): ≤ 0.0001 %
Ca (Calcium): ≤ 0.001 %
Co (Cobalt): ≤ 0.0005 %
Fe (Iron): ≤ 0.0010 %
K (Potassium): ≤ 0.0005 %
Mg (Magnesium): ≤ 0.0005 %
Na (Sodium): ≤ 0.01 %
NH₄ (Ammonium): ≤ 0.02 %
Zn (Zinc): ≤ 0.0005 %
Foreign amino acids: ≤ 0.5 %
Other ninhydrine positive substances: ≤ 0.1 %
Loss on drying (105 °C; 3 h): ≤ 0.5 %