Precision in ICP work doesn’t begin at the nebuliser; it begins at the bottle. Labs that treat their standards as afterthoughts will see it in drift, failed PT rounds, and unexplained bias. This post pulls together Inorganic Ventures’ technical guidance and standard lab practice into a single, actionable reference for Australian teams sourcing Inorganic Ventures certified reference material through Graham B Jackson. Use it to reduce contamination, improve reproducibility and get the most reliable lifetime out of your ICP/ICP-MS standards.
Handling: avoid the “double-dip” and control contact points
Contamination usually starts with how you touch and move standards. The simple rule is: never pipette directly from a stock bottle and never return unused liquid to it. Transfer working volumes into clean secondary containers (e.g., pre-rinsed LDPE or FEP bottles) and decant from there. This reduces cross-contamination risk, preserves the lot integrity and avoids introducing particulates or carryover from pipettes and glassware. Inorganic Ventures explicitly recommends secondary container use as a core SOP.
Practical checklist:
Use dedicated dispensing bottles per analyte family when possible (e.g., one bottle for multi-element standards, another for single-element spikes).
Never hold pipette tips against bottle necks; avoid touching caps or inner surfaces.
Label secondary containers with lot number, prep date, analyst initials and “Period of Validity” if different from the unopened lot expiry.
Temperature control: why climate matters more than you think
Temperature affects volume, density and—even subtly—stability. A volumetric flask filled at 30 °C will read differently once it equilibrates to a 20 °C lab bench; the apparent concentration shifts because density changes with temperature. For this reason, gravimetric preparation (weighing reagents and diluent) is inherently more accurate than volumetric approaches: mass does not change with temperature the way volume does. Inorganic Ventures’ ICP Operations Guide explains why gravimetric prep reduces this temperature-related bias.
Lab practice:
If you must prepare by volume, let solutions equilibrate to lab temperature (typically 20–23 °C) before final volume adjustment.
Record laboratory temperature when preparing critical calibration sets and consider adding temperature correction if your lab routinely runs outside the typical range.
Gravimetric preparation: more reproducible, less guesswork
Gravimetric (weight-based) preparation wins for precision and auditability. It avoids pipetting variability and the physical contraction/expansion errors that come with thermal changes. Use an analytical balance with appropriate calibration, tare against the container and document masses to two or three significant figures beyond what your method normally requires. This method also simplifies traceability because CRM certificates are typically weight-based and include density values referenced to 20 °C.
How to implement:
Keep a balance log and perform routine verification with standards (e.g., check weights with calibrated masses weekly).
Use weight-to-volume conversions (via certified density at 20 °C) only when necessary and record the conversion method in your SOPs.
Acid matrices, v/v vs w/w — understand what your concentration means
Acid strength expressed as “% v/v” can be misleading when combined with concentrated stock acids (e.g., 69–70% HNO₃). A nominal “5% HNO₃ v/v” does not equal 5% HNO₃ by weight; the real weight percentage depends on the stock acid density. Because analytical concentrations (ppm, ppb) are weight-based, always check the CRM COA for the reference temperature and density used to certify values. Inorganic Ventures’ materials and guides include conversion tools and recommended matrix conditions for ICP standards.
Tip: Prefer specifying acid matrices in molarity or w/w when writing SOPs that will be followed across multiple labs or ambient conditions.
Storage and expiry: what “shelf life” really means
There’s a lot of ambiguity in marketing around “stability” and “shelf life.” Inorganic Ventures separates the idea of chemical stability (many standards are chemically stable long term) from lot-based expiration or Period of Validity set for traceability and audit control. Treat the COA Lot Expiration Date as the controlling document unless you document specific verification testing for extended use.
Best storage practices:
Keep unopened bottles sealed, in original packaging, at recommended temperatures (check the COA).
For opened bottles, transfer working volumes into smaller, labelled bottles to reduce headspace and limit vapor exchange.
Refrigerate when recommended; always allow standards to reach room temperature before preparing calibration curves.
Store low-level standards away from strong acid sources (HCl vapour can cause “reverse transpiration” and contaminate ultra-trace metals).
Documentation and traceability: make your audits painless
A CRM is only as useful as the paperwork that accompanies it. Keep COAs, lot numbers and chain-of-custody in an indexed folder (electronic or printed). When your lab reports uncertainty budgets, the assigned values, expanded uncertainties and traceability statements on the COA are primary evidence for ISO/IEC 17025 audits. Inorganic Ventures’ ISO-accredited production and COA detail make this step straightforward—capture it in your LIMS or quality folder.
Troubleshooting: if numbers drift, check the process first
When calibration fails or drift appears, don’t reflexively blame the CRM. More often, issues are process-related—contamination from sample prep, improper handling, temperature swings, or reagent blanks. Inorganic Ventures’ practical troubleshooting notes strongly advise verifying handling, storage and reagent controls before re-ordering or re-testing standards.
Final thought
High-quality ICP data starts at the bench, with disciplined handling, measured preparation and thoughtful storage. For Australian labs sourcing Inorganic Ventures certified reference material via Graham B Jackson, integrating these best practices (gravimetric prep, secondary containers, clear documentation and controlled storage) will reduce variability, simplify audits and extend usable life for expensive standards. If you’d like, Graham B Jackson can help map these practices to your LIMS, supply chain and audit calendar—so you get the full value from every CRM bottle you open.
For Further Enquiry Contact: sales@gbjpl.com.au