Oxine sulfate, Quinolin-8-ol, CAS 134-31-6 – call it what you will, this lemon-yellow solid has quietly become the “Swiss-army knife” of industrial chemicals. Formally described as C₁₈H₁₄N₂O₂·H₂SO₄ (Mr 388.4 g mol⁻¹), it pairs a robust chelating scaffold with broad-spectrum bio-activity. The upshot? A single compound that protects lettuce from mildew one day and guards an anti-aging cream the next.

What you see on the benchtop

Fresh material arrives as bright canary crystals—eye-catching, yes—and tough as nails. Fire-tests gel at roughly 175 °C; long-chain decomposition doesn’t kick in until you’re well past 300 °C. With a density just a touch above 1.38 g cm⁻³ and a flash point nudging 298 °C, drums of Oxine sulfate can sit on a warehouse shelf for years without incident, provided they’re sealed from moisture. That stability explains why both undergrad labs and formulators trust it.

Here’s the chemistry bit: the quinolin-8-ol backbone acts as a monoprotic, bidentate chelator, latching onto Mg²⁺, Cu²⁺, Zn²⁺—practically any metal ion you throw at it—forming more stable complexes than EDTA at acidic pH. No wonder chemists reach for Oxine during trace-metal titrations or when they need to strip stubborn Cd(II) out of a mother liquor.

From farm plots to face creams

Antimicrobial prowess first put Oxine on the map. Field trials show fungistatic effects against Alternaria on tomatoes and RNase-inhibitory activity at 1–5 ppm in gene-expression assays. Surprisingly, it’s equally handy in petri dishes: many plant-cell culture media list the sulfate salt as a sterile “insurance policy.”

Agricultural pros know it as the active in copper-8-quinolinol sprays, but the story doesn’t stop at agronomy. Cosmetic chemists slip 0.1–0.3 % into lotions and shampoos, exploiting its dual role—chelates transition metals (goodbye oxidative rancidity) while checking bacterial growth. Win-win for everything from baby lotion to nickel-coated steel cutting-oil emulsions.

Fine-tuning purity for specific gigs

Not every job demands reagent-grade. Need grignard-grade material? Check out 8-Quinolinol hemisulfate salt—ethanol loves it. Synthesis folks working on OLED sub-strates swear by Bis(8-hydroxyquinolinium) sulfate: cleaner than 95 %, particle size controlled to <200 µm, and packed in amber glass so the fluorophore doesn’t photochemically age before it reaches your glovebox.

Laboratory note: Always dissolve in the more polar solvent first—DMSO, AcOH, or pH ‑ buffered Tris—then bring to target matrix. Many a grad student has learned the hard way that dumping Oxine straight into toluene does nothing but clog filters with microcrystals.

A last word, straight from the field

Whether you’re compounding a silicone-based leather finish or crafting a transfection media for Arabidopsis protoplasts, 8-Hydroxyquinoline sulfate has probably earned a square on your worksheet. Reliable, potent, and color-coded for quick identification—what’s not to love?