Sulfur

Location:  Group 16, Period 3
Atomic Weight:  32.066
Coordination Number:  6
Chemical Form in Solution:  (O)₂S(OH)₂

Storage & Handling:  Keep tightly sealed when not in use. Store and use at 20 ± 4°C. Do not pipet from container. Do not return portions removed for pipetting to container.

Chemical Compatibility:  Soluble in HCl, HNO₃, H₃PO₄, and HF aqueous matrices, water, and NH₄OH. Stable with all metals and inorganic anions at low to moderate ppm levels under acidic conditions, except Ba, Pb, Ca, and to a lesser extent Sr.

Stability:  2-100 ppb levels - stability unknown - in 1% HNO₃ / LDPE container. 1-10,000 ppm solutions chemically stable for years in LDPE container.

S Containing Samples (Preparation & Solution):  We most often get questions about the determination of S in rocks, silicates and insoluble sulfates (the finely powered sample is fused in a Pt⁰ crucible with 6 times its weight of Na₂CO₃ + 0.5 grams KNO₃. The fuseate is extracted with water. Any BaSO₄ present in the sample is transposed by the carbonate fusion to the BaCO₃, which is left behind in the water-insoluble residue. If PbSO₄ is present, the fuseate should be boiled with a sodium carbonate saturated with CO₂ solution for 1 hour or more. The PbSO₄ will be transposed to the water insoluble carbonate which can be filtered off. Boiling the fuseate with a saturated carbonate solution is good insurance for samples containing Ba, Sr, and Ca. The Ba, Pb, Sr, and Ca free filtrate can be acidified and measured by ICP).