Frequently Asked Questions

Store lyophilized peptides desiccated at −20 °C or below, protected from light and moisture — in this state most are stable for years. Once reconstituted, aliquot and freeze to avoid repeated freeze–thaw cycles.

They indicate the amino-acid residue range of the parent protein the peptide corresponds to. For example, (7-26) is the fragment spanning residues 7 through 26.

We routinely synthesize peptides up to 112 amino acids, including difficult sequences with multiple disulfide bridges. Send us your sequence for a feasibility assessment.

No. Peptides ship as a lyophilized powder in small quantities, so the material may be a thin film or barely visible at the bottom of the vial. Briefly centrifuge the vial before opening, then reconstitute as directed.

Our catalog lists 500+ peptide SKUs but doesn't cover everything. Send us your requirements and we'll quote a custom synthesis.

Custom synthesis typically starts at a few milligrams, with scale ranging from mg to kg. The minimum depends on sequence length and required purity — contact us for a quote.

Yes. We offer fluorescent, biotin, colorimetric, radioactive, and stable-isotope labeling of both custom and catalog peptides.

Extraction removes proteins and matrix components that interfere with assays, concentrating the target peptide to improve sensitivity and reproducibility.

Typically an appropriate anticoagulant, a peptidase inhibitor (e.g. aprotinin), and a solid-phase extraction column. Each EIA/RIA kit protocol specifies the recommended extraction materials for that analyte.

Collect with the recommended anticoagulant and inhibitors, separate promptly, and store at −20 °C (or −80 °C for long-term). Avoid repeated freeze–thaw cycles.

Frozen at −20 °C to −80 °C, most peptide analytes are stable for several months. For best results, assay as soon as practical.

Every order includes a Certificate of Analysis (COA), HPLC chromatogram, and mass spectrometry data. SDS, stability studies, and regulatory compliance documents are available on request.

Catalog peptides are typically HPLC ≥ 99%. Custom synthesis can be quoted to a purity specification you define. The COA reports the actual measured value, not the specification limit.

HPLC purity, mass spectrometry identity confirmation, endotoxin testing (LAL) where applicable, microbial limits, and residual solvents by GC. A batch is released only when all results meet specification.

We provide free COA samples for evaluation. Physical samples can be arranged in small quantities at competitive pricing — contact our sales team.

Yes. Standardized processes ensure consistent purity and content across production batches, with documented audit trails and retained samples for full traceability.

MOQ varies by product. Most peptides start from 5 mg for evaluation. Bulk orders range from grams to kilograms. Contact us for product-specific MOQ.

Stock items ship within 24–48 hours after QC clearance. Delivery is 3–5 days for Asia, 5–7 days for US/Europe, and 7–10 days for other regions. Express options are available.

Temperature-controlled packaging with cold packs where required. Peptides are shipped lyophilized and are stable at ambient temperature for the duration of transit.

Bank transfer (T/T), PayPal, Western Union, and major credit cards. For large orders we can discuss payment terms and letter of credit arrangements.

Store lyophilized peptides at −20 °C, protected from light and moisture. After reconstitution, aliquot and freeze to avoid repeated freeze–thaw cycles.

I-125 labeled tracers are supplied at a defined activity (µCi) referenced to a calibration date on the vial. See the datasheet for the exact value.

I-125 has a half-life of approximately 59.4 days.

Store at 2–8 °C behind appropriate shielding, following your institution's radiation-safety procedures. Do not freeze unless specified.

Use A = A₀ × (1/2)^(t / 59.4 days), where A₀ is the activity at the calibration date and t is the number of days elapsed.

Catalog peptides typically ship within a few business days; custom synthesis is usually 2–3 weeks depending on the sequence.

Labeled peptides require additional processing — plan on roughly 3–4 weeks for custom labeling.

In-stock RIA kits ship within a few business days, subject to availability.

Custom peptides typically take 2–4 weeks depending on sequence length, modifications and scale.

Stock items ship within 24–48 hours after QC clearance.

QIANMIAO supplies pharmaceutical companies, research institutions, cosmetic manufacturers, biotech firms and CROs. Products are for research, development and manufacturing use — not for direct human use.

Account approval requires business verification. Products are supplied for research, development and manufacturing use only.