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Frequently Asked Questions
30 answers on quoting, documents, freight, payment and grades, grouped by topic.
These answers cover the questions buyers ask us most often, grouped by topic: placing an enquiry, documents and quality, shipping and export, payment, product grades and custom synthesis.
For more detail, see how to order, quality and documentation and export and logistics. Grade questions are covered in depth in our chemical grades guides, and technical words are explained in chemistry terms.
If your question is not answered here, write to contact@zemixal.com with your CAS numbers and destination country, and we will reply by email.
Custom Synthesis
How does a custom synthesis project start?
Send the structure as a SMILES string, CAS number or drawing, with the quantity, target purity, data package and deadline. We review feasibility, ask any questions and send a proposal with an outline route, timeline and price. Work begins once you approve the proposal and any NDA is signed.
How is custom synthesis priced?
Most projects are quoted as a fixed price for a defined deliverable, such as 50 mg of a compound at 95 percent HPLC purity with NMR and MS data. Difficult or exploratory work may be quoted in stages. The proposal states what happens if the target cannot be reached, so the commercial risk is clear before work starts.
Who owns a compound made to my specification?
Unless agreed otherwise in writing, compounds made to your specification and the associated data are supplied only to you. Structures and project details are shared with our synthesis partner only as far as needed, under confidentiality terms. We are glad to sign a mutual NDA before you send anything sensitive.
What if the synthesis cannot be completed?
Some targets prove unstable or harder than expected. If that happens, we report what was tried, what was learned and any intermediate obtained, and discuss options such as a different route, a lower purity or a related compound. Any charge in this situation follows the terms agreed in the proposal.
Ordering & Quotes
How do I send one enquiry for several products?
Use the quote panel. On any product page choose the grade and pack size, add it to the panel and keep browsing. When your list is complete, open the panel, add your destination and any document needs, and send it as a single enquiry. You can also type a free-text line for items you could not find, and we will check them.
Can I check a whole list of CAS numbers at once?
Yes. Paste up to 200 CAS numbers into Bulk CAS lookup and the page shows which ones Zemixal lists, with links to each product. Add the matches to the quote panel in one step. Numbers that do not match are shown separately, so you can send them as free-text lines for sourcing or custom synthesis.
Can I get a sample before placing a larger order?
For most bulk and recurring items, yes. We can send a representative sample with its COA so you can test it against your own specification. Samples of dangerous goods are limited by courier rules, which sometimes means a larger minimum pack. Ask for a sample in your enquiry and state the quantity your test needs.
How long does a Zemixal quotation remain valid?
Each quotation shows its own validity date, typically 30 days for catalogue items. Freight, exchange rates and lot availability change, so prices for sea shipments or sourced items may be valid for a shorter period. If your purchase order will take longer to approve, tell us and we can confirm the lot or update the quote.
What should I include in an enquiry to get an accurate quote?
Give the product name and CAS number, the grade or specification, quantity and pack size, destination country and city, and your preferred Incoterm. Mention any documents you need beyond the COA and SDS, such as a certificate of origin or a pharmacopoeial statement. If the material is for a regulated use, say so early.
Payments
When do I need to pay for an order?
New customers normally pay in advance by bank transfer, or by letter of credit for larger orders. Payment terms are stated on the proforma invoice. For established customers with regular orders, other terms may be discussed after a credit review. Stock items are prepared for dispatch once payment has cleared.
How can I be sure your bank details are genuine?
Zemixal bank details appear only on the proforma invoice. We never change them by email alone. If you receive a message saying our account has changed, do not pay. Start a new email to contact@zemixal.com, typing the address yourself, and ask us to confirm before any transfer.
Who pays bank charges on international transfers?
Charges raised by your bank and any intermediary bank are normally for the buyer's account, so the full invoice amount should reach us. Please instruct your bank to send the payment with charges paid by the sender. Charges raised by our own bank in India are normally ours, unless the quotation says otherwise.
Can universities and public bodies order with a purchase order?
Yes. Send your purchase order referencing our quotation number, and we will issue a proforma invoice that matches it. Many institutions pay by bank transfer after the order is confirmed. If your rules require payment after delivery, tell us when you request the quote so we can agree the terms in advance.
Are samples and quotations charged?
Quotations are free and carry no obligation. Small samples of catalogue products may be free or charged at a nominal rate, depending on the product and freight cost. Samples of reference standards and custom compounds are normally charged. Courier costs for samples are stated before anything is sent.
Products & Grades
How do I choose the right grade for my application?
Start with the grade your method or monograph names. If none is named, choose by how the chemical is used: technical grade for processes, LR or extra pure for synthesis, AR or ACS for quantitative analysis and HPLC or LC-MS grade for chromatography. Our chemical grades pages explain each one in detail.
What is a ZX catalogue number?
Every Zemixal product has a ZX number that identifies one substance in one grade. It appears on the product page, quotation and label, and you can search for it directly. Quoting the ZX number avoids confusion between salts, hydrates or grades that share a name or CAS number.
Can I compare products before requesting a quote?
Yes. Add products to compare from their pages to view grade, purity, formula, molecular weight and pack options side by side. This is useful when a substance is offered as different salts or grades. From the compare view you can send any of the products straight to the quote panel.
Can you supply a grade or pack size that is not shown?
Often, yes. Product pages show the grades and packs most often requested, but producers may offer others. Add the product to the quote panel and describe the grade, specification or pack size you need. We will confirm whether a matching source exists or suggest the closest alternative.
Are your products intended for research use only?
Most products are sold for laboratory, research and industrial use. Materials offered with pharmacopoeial (USP/EP/BP/IP) grade documentation where the grade exists can be used in regulated manufacture, but the buyer remains responsible for supplier qualification and regulatory approval. Product labels and quotations state the intended use.
Quality & Documents
Can I see a certificate of analysis before I order?
Yes. For stock items we can send the COA of the lot we would ship, so you can compare its results with your specification before paying. For sourced or made-to-order items we send a representative COA or the producer's specification, and the lot COA follows with the shipment.
Can the SDS be provided for my country's format or language?
Every shipment includes a 16-section GHS SDS in English. Many producers can also issue versions aligned with EU CLP, US OSHA or other national formats, and some offer translations. Ask at the quotation stage and we will confirm what is available before you order.
What data comes with an impurity or reference standard?
Reference standards ship with a COA giving identity, chromatographic purity and, where relevant, an assigned assay value. Supporting data usually includes HPLC, NMR and MS, with IR, water content or residual solvents as the molecule requires. Spectra are sent as PDF files so your laboratory can review them directly.
How can I trace a product back to its production lot?
Every container is labelled with its lot number, which matches the COA and our dispatch records. Quote the lot number in any query and we can retrieve the producer's records, the documents sent with your order and, where the producer keeps one, information about the retained sample.
What happens if a product does not match its certificate?
Write to contact@zemixal.com within 30 days of delivery with the lot number, your test method and results. We review your data with the producer's records and may ask for a portion of the material for retesting. If the non-conformity is confirmed, we replace the product or refund what you paid, as set out in our returns policy.
Shipping & Export
Which ports and airports do you ship from?
Sea freight leaves from Nhava Sheva (JNPT) near Mumbai or from Mundra in Gujarat, depending on the destination and sailing schedule. Air cargo moves through Mumbai (BOM) or Ahmedabad (AMD). Small packs travel by express courier. The quotation names the route we plan to use.
Can you deliver duty paid to my door?
In some countries we can quote DDP, where Zemixal pays import duties and taxes and the courier or forwarder clears customs for you. It depends on whether a reliable clearance partner is available and on the product's import rules. Where DDP is not practical, we offer DAP or CIP and you handle import clearance.
How are small gram-scale orders shipped?
Reagents, standards and samples usually go by international express courier. Non-hazardous items and dangerous goods in excepted or limited quantities can often travel this way. Some substances cannot go by courier at all, and we tell you at the quotation stage if a different route is needed.
Which shipping documents will I receive?
A commercial invoice, packing list, COA for every lot and a GHS SDS for every product. Air and sea shipments add an air waybill or bill of lading, and dangerous goods add a declaration. We can also arrange a certificate of origin. Copies are emailed as soon as the goods leave us.
Can several products be combined into one shipment?
Yes, as long as transport rules permit. Some dangerous goods cannot share a package or container with others, such as oxidisers and flammable liquids. We plan consolidation to keep freight costs down while respecting segregation, and explain if part of an order must travel separately.
What should I do if a package arrives damaged?
Note the damage on the delivery receipt if possible, take photographs of the outer packaging and contents, and email contact@zemixal.com within 7 days. Keep the packaging until the claim is settled. We work with the carrier and arrange a replacement or credit once the claim is assessed.