Quality control materials — spiked wipes, blanks and reference standards.

Why known-value materials matter

Every result in surface residue testing rests on an assumption that is rarely tested: that the residue which was on the surface actually made it into the container, and that nothing else did. Quality control materials are how that assumption is replaced with evidence.

A spiked wipe carries a known quantity of a known compound. Submit it blind through your normal process — same handling, same transport, same laboratory — and the result tells you what your recovery genuinely is. A field blank carries nothing, and its result tells you whether your kit, your technique or your transport chain is introducing residue that was never on the building.

Together they close both ends of the uncertainty. Without them, a laboratory report is a statement about a wipe. With them, it becomes a statement about a surface, which is what the client actually asked about.

What we supply

All materials are prepared in our Queensland laboratory to the concentration and analyte mix you specify, using certified reference standards. Nothing is held as generic stock, because the useful concentration depends entirely on what you are demonstrating.

• Spiked wipes at nominated concentrations, including levels bracketing the 0.5 µg/100 cm² guideline
• Multi-analyte spiked wipes covering stimulants, precursors or the full nine-compound panel
• Matched field blanks prepared from the same wipe lot as the spikes
• Low-level spikes near the reporting limit, for demonstrating method sensitivity
• Reference materials for laboratory calibration checks and instrument performance verification
• Preparation documentation stating the analyte, nominal concentration and preparation date

Method validation for laboratories

Laboratories introducing or revalidating a surface residue method need materials that behave like real samples rather than clean standards in solvent. Spiked wipes on the same substrate your clients will actually use let you characterise extraction recovery, precision and the practical reporting limit of the method as it will be run day to day.

We prepare validation sets across a concentration range so you can establish linearity and recovery across the working range, with replicates at each level for precision. Where a laboratory is validating for multiple analytes, multi-compound spikes reduce the number of extractions required without compromising the exercise.

Preparation records accompany every batch, stating the analyte, the nominal loading and the date of preparation, so the materials can be referenced directly in your validation report.

Proficiency and inter-laboratory comparison

Proficiency testing is the most direct way a laboratory or a hygienist practice can demonstrate ongoing competence to a client, an insurer or an auditor. We prepare blind sets at concentrations not disclosed to the participant, which are submitted through the normal workflow and reported back against the nominal values.

Hygienist practices use the same approach to compare laboratories. Splitting a set of identically prepared spiked wipes between two or more laboratories and comparing the results is far more informative than comparing price lists, and it is a conversation we are happy to be on the receiving end of.

Where a result falls outside expectation, we work through it rather than simply reporting the deviation. Most discrepancies trace back to handling, storage temperature or transport time rather than to the analysis, and identifying which is the whole point of the exercise.

Field QA/QC and sampler competency

For remediation and cleaning contractors, the most valuable use of these materials is demonstrating that the people collecting samples are collecting them properly. A technician who samples a spiked wipe and returns a result close to the nominal value has demonstrated their technique against a number rather than an opinion.

Running blanks as routine field QA is equally important. A crew that includes a field blank on every job builds a record showing their sampling has never introduced contamination — which is exactly the record you want on hand the first time a result is disputed.

Contractors running decontamination verification also use spiked materials to validate their cleaning procedures. Apply a known loading to a representative substrate, clean it with your documented procedure, then sample and analyse. The result quantifies how effective the procedure actually is on that material, rather than relying on the supplier's claims.

Handling, storage and ordering

Spiked wipes are supplied sealed and labelled with their identifier and preparation date. Store them cool, out of direct light and sealed until use, and submit them within the recommended period stated on the preparation record — loadings are stable for practical purposes over that window, but they are not indefinite.

For blind submissions, we can label materials with neutral identifiers so the technician handling them cannot distinguish a spike from a field sample. Tell us how you want the exercise structured and we will prepare the set accordingly.

To order, let us know the analytes, the concentrations, the number of wipes and whether you need matched blanks. We prepare to order and dispatch anywhere in Australia. Call the laboratory on 1300 522 115 or send an enquiry, and if you are not sure what concentrations would suit your program we will help you design it.