Compare bulk sodium thiosulfate quotes only after matching chemical form, grade, assay basis, impurity limits, granule size and quantity. Then confirm packaging and the costs included in each written offer. Use one purchase specification for every quotation so the price comparison refers to the same material and delivery requirement.
A comparable quote starts with a complete product description
A quote for crystals, a quote for powder and a quote with a different impurity limit may all say “sodium thiosulfate.” The buyer needs enough detail to decide whether they meet the same requirement.
Match the chemical form before comparing price
Start by writing the full product name into the comparison sheet. V&S lists sodium thiosulfate pentahydrate with the formula Na2S2O3·5H2O and CAS number 10102-17-7 on its 1–3 mm product page. The same page also publishes an anhydrous grade as white powder in its grade table.
The V&S pentahydrate-versus-anhydrous guide explains why the two forms require different masses for the same chemical equivalent. A price per tonne comparison across those forms needs an agreed assay and conversion basis, as well as confirmation that the alternative form suits the process.
Keep equivalent-mass calculations separate from product approval. Matching chemical content does not establish that powder and granules will work in the same feeder, preparation tank or purchasing specification.
If the process already specifies pentahydrate, ask each seller to quote that form. If an alternative is offered, identify it as an alternative and have the process owner review the change before treating it as interchangeable.
Attach one specification to every quotation request
V&S publishes both a compact 99% granule specification and a separate grade comparison. Those tables contain different limits. A buyer should name the exact specification being requested and ask the quotation to confirm each field.
| Field | Published value | What to confirm in the offer |
|---|---|---|
| Product form | Pentahydrate | Full chemical name, formula and CAS number |
| Sodium thiosulfate | 99% minimum | Content definition, assay basis and test method |
| Water-insoluble substance | 0.01% maximum | Same limit in the quoted specification |
| Na2S field | 0.001% maximum | Correct analyte name and test method |
| Iron, Fe | 0.002% maximum | Applicable limit for this product specification |
| pH | 6.5–9.5 | Measurement conditions in the current specification |
The figures above come from the V&S product listing. Its compact table labels the Na2S entry “sulphate,” while the grade table uses “Sulfide.” Confirm the analyte wording on the current specification supplied with the quotation.
The V&S COA guide also explains the difference between the compact product limits and the photographic, industrial and anhydrous grade columns. Use that guide to review the technical document; use the quote comparison to establish whether each offer covers the same approved material.
Specification
Defines what the buyer agrees to purchase. Record the document version, product name, limits and reporting basis used for the quotation.
Batch COA
Reports results for the supplied batch. Confirm that its identity and results can be checked against the specification referenced in the order.
State the granule size as a separate line item
V&S lists pentahydrate in 1–3 mm, 3–5 mm and 5–8 mm sizes. Its granule-size guide discusses their different dissolution and handling behavior. The required size should appear in the RFQ even when the chemical name and assay already match.
When a supplier proposes another size, ask whether the offer is for the requested range or an alternative. Record the difference before comparing price. A trial in the intended equipment can answer handling questions that the assay result cannot.
Compare the written delivery scope
After technical suitability is established, put the commercial details beside each offer. Treat missing information as a question to resolve. An omitted cost or term should not be assumed to be included.
| Comparison field | Ask each quotation to state | Buyer decision |
|---|---|---|
| Price and currency | Currency, unit and quantity covered | Are the quoted units and order quantities equivalent? |
| Net quantity | Net product weight and permitted quantity variation, if any | Does the comparison use product mass rather than gross shipping weight? |
| Packaging | Pack type, net weight per pack, liner, pallet and label requirements | Does the offer match receiving and warehouse needs? |
| Delivery terms | Agreed trade term, named place and included transport services | Which charges remain for the buyer to obtain? |
| Documents | Specification, COA, SDS and requested shipment documents | Can the technical and receiving teams review the required files? |
| Timing | Availability, dispatch proposal and quotation validity | Does the written schedule fit the purchasing requirement? |
| Payment | Proposed payment terms | Have purchasing and finance accepted the same terms? |
| Changes or exceptions | Any substitution, excluded service or specification deviation | Has each difference been reviewed before selection? |
These are comparison questions, not published V&S promises. Request a written offer for the required product, quantity, packaging and destination through the V&S contact page.
Build a comparable cost total
List the quoted goods amount and any separately confirmed packaging, transport, inspection or destination charges that apply to the purchase. Keep the destination and delivery scope consistent across the comparison. Where a charge is unknown, leave it unresolved until a written amount is available.
For quotes in different currencies, record the conversion basis used by your purchasing team. For different chemical forms, complete the technical equivalence review first. A cost worksheet is useful only after the materials and included services have been defined.
Video: why hydrate form affects a weight comparison
The independent chemistry lesson below explains water of crystallization and hydrate calculations. It also appears in the V&S form-comparison guide. It provides background for understanding the full chemical name on a quotation.
Use a complete RFQ to reduce quotation revisions
The template below gives the supplier a clear starting point. Replace the bracketed text with the requirement already agreed by your technical and purchasing teams. Leave proposed alternatives visible so they can be reviewed separately.
Subject: Bulk sodium thiosulfate quotation request
- Product
- [Full name and hydrate form]
- Identification
- [Formula and CAS number]
- Specification
- [Attach the approved specification and version]
- Particle form
- [Powder or required granule range]
- Application
- [Process and preparation or feeding method]
- Quantity
- [Net order quantity and expected repeat demand]
- Packaging
- [Pack, liner, pallet and label requirements]
- Destination
- [Named place and requested delivery terms]
- Documents
- [Current specification, representative COA, SDS and shipment document requests]
- Commercial details
- [Currency, validity, availability, dispatch proposal and payment terms requested]
- Alternatives
- [Ask the supplier to identify every proposed deviation]
V&S's complete sodium thiosulfate buyer's guide covers the broader grade, application and sourcing decisions. Once those choices are settled, the RFQ can focus on an offer for the specified product.
Before selecting the offer, close the open questions
- Technical match: confirm that product form, assay basis, impurity limits and particle form meet the approved requirement.
- Commercial match: confirm quantity, packaging, destination, included costs and written terms.
- Document match: confirm the quotation and purchase specification use the same product identity and version.
- Exceptions: obtain a decision on every substitution or missing field before issuing the order.
Keep the completed comparison with the quotation and purchase order. It gives receiving staff a clear record of what was approved and helps repeat orders use the same basis.
Bulk quotation questions
Can I compare pentahydrate and anhydrous sodium thiosulfate by price per tonne?
A direct price-per-tonne comparison does not establish chemical equivalence. Confirm the hydrate form, assay basis and approved mass conversion, then review whether the alternative physical form suits the process.
Does a 99% assay mean two quotations cover the same product?
No. The chemical form, impurity limits, pH range, particle form and reporting basis also need to match. Use one approved specification for both quotations.
Which granule size should appear in the RFQ?
State the range required by the preparation tank or feeder. V&S lists 1–3 mm, 3–5 mm and 5–8 mm sodium thiosulfate pentahydrate products.
What if a quotation leaves packaging or freight unclear?
Request written clarification of the pack requirement, delivery scope and included costs before comparing totals. Keep unresolved charges visible in the comparison sheet.
Request a quote against your sodium thiosulfate specification
Send V&S Chem your chemical form, grade, granule size, quantity, packaging and destination. Attach the required specification and ask for the corresponding product documents and a written commercial offer.
Send your quotation request
