Product Storage & Shelf Life¶

Storage by Category¶

Product Category	Storage Temperature	Special Handling	Shelf Life (Unopened)	Shelf Life After Opening
PCR Master Mixes	-20°C	Avoid multiple freeze-thaw	24 months	12 months (aliquot recommended)
qPCR Master Mixes	-20°C	Light-sensitive, dark container	24 months	6 months (aliquot; ≤5 freeze-thaw cycles)
DNA Polymerases	-20°C	Aliquot to avoid freeze-thaw	24 months	12 months
DNA Extraction Kits	RT (15–30°C)	Keep dry, sealed	24 months	12 months
RNA Extraction Kits	RT (15–30°C)	Avoid RNase contamination	24 months	12 months
Competent Cells	-80°C (long-term); -20°C (<1 month)	Do not thaw until use	12 months	Single-use only
ELISA Kits	2–8°C	Do not freeze	12 months	Use entire kit within 1 month of opening
Antibodies	-20°C or 2–8°C	Aliquot if repeated use	24 months	12 months (glycerol-containing); 3 months (PBS-only)
Assay Kits	2–8°C or as labeled	Check each component	6–12 months	Kit-specific (usually 1 month)
Buffers & Solutions	RT (15–30°C)	After opening, store 2–8°C	24 months unopened	6 months
Small Molecules	-20°C	Desiccate, N₂ blanket	24 months	12 months (stock solution in DMSO: 1–3 months)
Analytical Standards	2–8°C or as labeled	Desiccate, tightly sealed	36 months	6 months after opening (verify before use)
Staining Dyes	RT or -20°C	Light-sensitive, dark container	12–24 months	6–12 months
Bovine Sera	-20°C	Avoid repeated freeze-thaw	24 months	6 months (thawed, stored 2–8°C)

Product Type	Recommended Freeze-Thaw Cycles	Storage Format Recommendation
Taq DNA polymerase (in mix)	≤ 20 cycles	50 µL single-use aliquots
qPCR master mixes	≤ 5 cycles	100 µL single-use aliquots
Reverse transcriptase	≤ 5 cycles	10 µL single-use aliquots
Proteinase K	≤ 10 cycles	100 µL aliquots
Antibodies	≤ 3 cycles (aliquot recommended)	5–10 µL per aliquot
Bovine sera	≤ 3 cycles	50 mL aliquots
Cell lysates	≤ 3 cycles	Single-use aliquots
Primers (100 µM stock)	≤ 10 cycles	10 µL working aliquots + 100 µL master stock
Small molecule stock solutions	≤ 5 cycles	10–20 µL aliquots

Product Category	4°C (short-term)	25°C	37°C	56°C
2×Taq PCR Mix	1 month (stable)	7 days (>95% activity)	48 h (>90% activity)	2 h (50% activity loss)
SYBR Green qPCR Mix	2 weeks (>90% activity)	48 h (>95%)	24 h (>90%)	1 h (significant loss)
DNA (purified)	6 months	1 month	2 weeks	1 week
BSA (standard)	12 months	6 months	1 month	1 week
Small molecule (DMSO stock)	3 months	1 month	1 week	48 h

Products that require light-protected storage (amber vials, foil-wrapped, dark container):

Product Type	Light Sensitivity Level	Protection Recommendation
DAPI, Hoechst dyes	High	Foil-wrapped, -20°C
FITC and FITC conjugates	High	Amber tubes, -20°C
SYBR Green in qPCR mixes	Moderate	Dark container at all times
Fluorescent probes (DCFH-DA, JC-1, Fluo-4)	High	Desiccated, dark, -20°C
Oil Red O	Moderate	Amber bottle, RT
Curcumin, resveratrol	Moderate	Amber vial, -20°C
qPCR master mixes (SYBR)	Moderate	Manufacturer's dark tube

Unopened products should not be used beyond the printed expiration date
After opening, record the opening date on the vial/label
Discard if any of the following is observed:
Visible precipitation, turbidity, or discoloration (solutions)
Clumping or moisture absorption (powders)
Change in pH by >0.3 units (buffers)
Unexpected assay results (kits, enzymes, antibodies)
Growth of microbial contamination (media, buffers)
For products without printed expiration, apply the general rule: unopened = 24 months from receipt; opened = 6 months