Pharmaceutical grade Ferrous Sulfate must strictly adhere to international pharmacopoeia standards such as USP (United States Pharmacopeia), BP (British Pharmacopeia), or EP (European Pharmacopoeia). Key specifications include a purity level (assay) typically between 98% and 105%, and stringent limits on heavy metals. Specifically, Lead (Pb) must be ≤ 2ppm, Arsenic (As) ≤ 2ppm, and Mercury (Hg) ≤ 1ppm. Buyers must request a Certificate of Analysis (COA) for every batch to verify these parameters.