PH indicator range: 4.5（red）~6.2（yellow）

Residue on ignition (as sulfate): 0.2%max

Mass-absorption coefficient λ1（PH4.5）,L/(cm·g): 130min

                                        λ2（PH6.2）,L/(cm·g): 70min

Maximum absorption wavelength λ1（PH4.5）,nm: 523~528

   λ2（PH6.2）,nm: 427~437

Loss on drying: 1.0%max