... : Brownish liquid1. Usage :Good substitute of solid ferric chloride. In photoengraving; photography; manufacture of other Fe salts, pigments, ink; ... printing textiles; oxidizing agent in dye manufacute. Clinical reagent (amino acids in urine, esp in phenylketonuria). HPFCS type meets the high requirements ... 40Density (20°C), g/cm3≥1.43FeCl2, %≤0.4Non-soluble in water, %≤0.5Free acid (HCl) %≤0.5Cu, %≤0. ...