How quickly can you ship a standard from stock?+
Stocked reference standards typically ship within 1–3 business days of order confirmation, subject to documentation requirements. Lead times are among the shortest in the industry.
What documentation comes with each compound?+
Every order ships with a complete Certificate of Analysis, including characterization data (such as HPLC, NMR, MS, IR, GC, and other analytical techniques, as applicable), assigned purity, lot number, and storage guidance, along with a Safety Data Sheet (SDS).
Can you synthesize a compound that isn’t in your catalog?+
Yes. Custom synthesis is a core capability — we take on complex synthesis projects for impurities, nitrosamines, glucuronides, metabolites, stable isotope labeled compounds, and peptide drug standards, handling route development in-house. Send a structure or CAS number and our team will respond with feasibility, lead time and a quote.
How should reference standards be stored?+
Storage conditions are compound-specific and listed on each Certificate of Analysis. Many standards are stable at controlled room temperature, while others require refrigeration or freezing. Always follow the conditions stated for your specific lot.
Which accreditations does TLC hold?+
TLC is accredited to ISO 17034 (reference material producer), ISO 17025 (testing and calibration laboratories) and ISO 9001 (quality management system).
Do you offer stable isotope labeled internal standards?+
Yes. We produce deuterium, ¹³C and ¹⁵N-labeled internal standards for LC-MS/MS bioanalysis and DMPK studies, made to track your exact analyte.
Why did my impurity arrive at room temperature when the label says “Store at -20°C”?+
Many samples are stable during short-term transit but require long-term storage at sub-zero temperatures to prevent degradation over months or years. Cold packs are included with these shipments to help maintain short-term stability.
How are hygroscopic or air-sensitive impurities packaged?+
Vials containing sensitive samples are vacuum sealed and placed with silica gel to prevent moisture absorption during transit.
Do you provide international customs clearance assistance for restricted substances?+
Yes, we provide the commercial invoice, HS codes, and any required declarations of conformity. If the sample requires a license or import permit in your country, our compliance team will contact you to obtain all documentation before dispatch.
Do I need an Import Permit?+
While we handle standard export paperwork, many jurisdictions require the Importer of Record to hold specific domestic licenses depending on the sample. It is the buyer’s responsibility to provide a valid copy of their import permit when applicable.
What Harmonized System (HS) codes do you use for reference standards?+
Most of our products are classified under Chapter 29 (Organic Chemicals) or Chapter 38 (Miscellaneous Chemical Products) of the international Harmonized Tariff System. The exact HS code for your specific sample will be provided on the commercial invoice.