1. Foundational Principles: Pre-Storage Preparation

• Read the Safety Data Sheet (SDS) and Label First

   

  The SDS (formerly MSDS) and product label are the most authoritative sources for storage/handling instructions. They specify hazardous properties (e.g., flammable, corrosive, toxic, oxidizing), required storage conditions (temperature, light, humidity, ventilation), compatibility with other chemicals (e.g., "do not store with strong acids"), and expiration date (critical for reagents like titrants or reference standards—expired products must be discarded).
• Inspect Products Upon Receipt

   

  Check for damage (e.g., cracked vials, leaking containers, torn packaging) immediately. For sealed reagents (e.g., ampoules of standards), ensure no air or moisture has entered. If damaged, isolate the product and contact the supplier for replacement.
• Classify Products by Hazard and Compatibility

   

  Group products into categories to prevent cross-contamination or hazardous reactions. Common classifications include flammables (e.g., acetonitrile for HPLC, ethanol), corrosives (e.g., concentrated H₂SO₄, NaOH solutions), toxics (e.g., heavy metal standards like Pb²⁺, cyanide reagents), oxidizers (e.g., KMnO₄, peroxides), and light-sensitive reagents (e.g., iodine solutions, some fluorescent dyes).

2. Storage Best Practices: Environment, Containers, and Organization

A. Control the Storage Environment

• Temperature: Always store products at the labeled range (never guess!) and avoid temperature fluctuations (e.g., near lab doors/windows or heating vents). For example:
  • Refrigerated (2–8°C): Enzymes, some antibodies, aqueous standards (e.g., glucose solutions).
  • Frozen (-20°C/-80°C): Lyophilized reference materials, sensitive reagents (e.g., PCR primers).
  • Room temperature (15–25°C): Most solid reagents (e.g., NaCl, KCl), non-aqueous solvents (e.g., methanol).
• Light: Store light-sensitive products in amber glass containers or opaque storage cabinets, and avoid direct sunlight or UV exposure. Typical light-sensitive products include iodine, potassium iodide (KI), silver nitrate (AgNO₃), some HPLC detectors (e.g., fluorescent standards), and vitamin solutions.
• Humidity: Keep humidity below 60% (use desiccants like silica gel in cabinets for hygroscopic products) and never store open containers in humid areas (e.g., near sinks). Hygroscopic reagents (e.g., NaOH pellets, CaCl₂) and powdered standards are particularly sensitive to moisture, as are Karl Fischer titration reagents (which absorb moisture and lose accuracy).
• Ventilation: Use fume hoods or vented storage cabinets for volatile/toxic products, and ensure general lab ventilation is functional. This applies to volatile solvents (e.g., chloroform, acetone), toxic reagents (e.g., benzene, mercury standards), and corrosive gases (e.g., HCl fumes from concentrated solutions).

B. Choose the Right Storage Containers

• Glass containers: Ideal for most reagents (especially acids, bases, and organic solvents) because they are inert and non-porous. Use borosilicate glass (e.g., Pyrex) for thermal stability (resists cracking from temperature changes). Note: Do not store strong alkalis (e.g., 10M NaOH) in glass long-term—they react with silica to form silicates, which contaminate the reagent. Use HDPE (high-density polyethylene) plastic containers for alkalis instead.
• Plastic containers: Suitable for alkalis, hydrofluoric acid (HF, which reacts with glass), and some aqueous solutions. Avoid low-density polyethylene (LDPE) for organic solvents, as solvents may leach plasticizers into the reagent.
• Sealing: Always use tight-fitting caps (e.g., Teflon-lined caps for organic solvents to prevent evaporation and contamination). For opened vials of standards, use crimp seals or screw caps with O-rings to maintain purity.

C. Organize Storage Areas for Safety and Accessibility

• Separate incompatible chemicals: Never store flammables with oxidizers (risk of fire/explosion), keep acids and bases in separate cabinets (e.g., HCl and NaOH can react violently if spilled), and store toxic heavy metals (e.g., Pb, Cd) away from food/drinks (even in lab fridges—use a dedicated "chemical-only" fridge).
• Label everything clearly: For repackaged reagents (e.g., transferring a solvent from a large bottle to a small vial), label with product name, concentration, date of repackaging, expiration date, and your initials. Use color-coded labels for hazards (e.g., red for flammables, yellow for corrosives) to speed up identification.
• Store heavy items low: Place large or heavy containers (e.g., 20L solvent drums) on lower shelves to prevent tipping and injury.

3. Handling Protocols: Minimize Contamination and Risk

A. Personal Protective Equipment (PPE): Always Wear the Right Gear

• Gloves: Use chemical-resistant gloves (e.g., nitrile for organic solvents/acids; neoprene for alkalis; butyl rubber for HF). Avoid latex gloves (many solvents dissolve latex, and they offer poor chemical protection).
• Eye protection: Safety goggles or a face shield (required for corrosives, volatile liquids, or products that can splash).
• Lab coat: A flame-resistant lab coat (for flammables) or chemical-resistant coat (for corrosives) to protect clothing and skin.
• Respiratory protection: A fume hood (preferred) or N95/respirator (if fumes are unavoidable, e.g., for ammonia solutions) to prevent inhalation of toxic vapors.

B. Avoid Contamination

• Use clean, dedicated tools: For pipetting, use sterile, disposable pipette tips (never reuse tips for different reagents); for volumetric flasks, rinse with the reagent itself (3x) before use to remove residual water. For weighing, use clean, dry weighing boats or paper (never weigh directly on the balance pan) and clean the balance after use to remove spills (e.g., with a lint-free wipe).
• Do not return excess reagent to the original container: Pouring unused reagent back risks contaminating the entire stock (e.g., if your pipette tip was contaminated). Dispose of excess per lab waste rules.
• Keep containers closed when not in use: Open vials/bottles for the shortest time possible. For hygroscopic reagents (e.g., Na₂CO₃), use a desiccator during weighing to prevent moisture absorption.

C. Handle Volatile, Corrosive, or Toxic Products with Extra Care

• Volatiles (e.g., acetonitrile, methanol): Open only in a fume hood to avoid vapor inhalation; use a syringe or pipette with a bulb (never mouth pipetting—never do this!) to transfer; ensure the work area is free of ignition sources (e.g., Bunsen burners, hot plates).
• Corrosives (e.g., HCl, H₂O₂): Add acids to water (never water to acids!) to prevent exothermic splashing; if spilled, neutralize first (e.g., use baking soda for acids, vinegar for bases) before cleaning.
• Toxics (e.g., heavy metal standards, cyanides): Use a dedicated fume hood and avoid skin contact; collect all waste (e.g., pipette tips, weighing paper) in a labeled "toxic waste" container (do not mix with regular waste).

4. Special Considerations for High-Value/High-Sensitivity Products

A. Reference Standards and Certified Reference Materials (CRMs)

• Store at the exact temperature specified (e.g., -20°C for lyophilized CRMs) to prevent degradation.
• Once reconstituted (e.g., a 1000 ppm metal standard), label with the reconstitution date and use within the recommended timeframe (usually 1–4 weeks, even if refrigerated).
• Avoid repeated freeze-thaw cycles (aliquot reconstituted standards into small vials and freeze individual aliquots for single use).

B. Chromatography Supplies (e.g., HPLC Columns, Syringes)

• Columns: Flush with a storage solvent (e.g., 80:20 acetonitrile:water for C18 columns) after use to remove residual sample; store upright at room temperature (or 4°C for long-term storage) and cap both ends to prevent drying (a dried column is irreparable).
• Syringes: Clean with an appropriate solvent (e.g., methanol for organic samples, water for aqueous samples) after each use to prevent clogging; do not use syringes with corrosive solutions (e.g., HF) unless they are made of inert materials (e.g., PTFE).

C. Enzymes and Biochemical Reagents

• Store frozen (-20°C/-80°C) unless labeled otherwise.
• Thaw slowly on ice (not at room temperature) to preserve activity.
• Once thawed, use immediately (most enzymes lose activity within hours at room temperature).

5. Routine Maintenance and Monitoring

• Check storage conditions regularly: Use thermometers/hygrometers in fridges, freezers, and storage cabinets to log temperatures daily (address fluctuations immediately, e.g., a fridge at 10°C needs repair); replace desiccants (e.g., silica gel) when they turn from blue to pink (indicating saturation).
• Rotate stock: Use the "first in, first out (FIFO)" rule—place newer products behind older ones to ensure expired reagents are not used.
• Dispose of expired/ degraded products promptly: Follow local regulations for chemical waste disposal (e.g., incineration for flammables, neutralization for corrosives). Do not pour chemicals down the drain unless explicitly allowed by the SDS.

Summary

1. Follow the SDS/label (never deviate from manufacturer instructions).
2. Control the environment (temperature, light, humidity, ventilation) to maintain stability.
3. Minimize contamination and risk (use PPE, clean tools, and separate incompatible chemicals).