Honeywell B&J Water, >99.9% purity, LC-MS grade. Minimal organic and trace metal contamination, which results in higher ionization efficiency and lower adduct formation. CAS 7732- 18-5 Max. 1 ppm non-volatile matter; Max. 50ppb (negative mode as 4-nitrophenol,) max 100ppb (positive mode as caffeine,) max 50ppb (positive mode as reserpine.) NOTE: This item ships directly (ground) from our supplier, and due to Hazmat restrictions, overnight delivery is not possible.