L-组氨酸单盐酸盐一水合物，L-Histidine monohydrochloride monohydrate；for biochemistry, ≥ 99.0%

Assay (alkalimetric, calculated on dried substance): ≥ 99.0 %
Identity (IR-spectrum): passes test
Appearance: white to almost white crystalline powder or colorless crystals
Appearance of solution (50 g/l CO₂-free water): clear and colorless
Spec. rotation (α 20/D, 110 g/l, hydrochloric acid 120 g/l, calc. on dried substance): +9.2 to +10.6
Sulfate (SO₄): ≤ 0.02 %
Heavy metals (as Pb): ≤ 0.001 %
As (Arsenic): ≤ 0.0005 %
Ca (Calcium): ≤ 0.001 %
Co (Cobalt): ≤ 0.0005 %
Fe (Iron): ≤ 0.0005 %
K (Potassium): ≤ 0.0005 %
Mg (Magnesium): ≤ 0.0005 %
Na (Sodium): ≤ 0.005 %
NH₄ (Ammonium): ≤ 0.01 %
Zn (Zinc): ≤ 0.0005 %
Foreign amino acids: ≤ 0.3 %
Other ninhydrine positive substances: ≤ 0.1 %
Loss on drying (150 °C): 7.0 - 10.0 %