What a Microplastics Test Actually Tells You

Microplastics results are often reduced to a binary: found or not found.

A report says none detected, a label says tested, and the conclusion seems obvious. There were no microplastics in the water.

The real answer is more precise. Particle testing has a boundary that ordinary chemical testing does not: size. A laboratory can find no particles above its stated threshold while leaving smaller particles outside the result.

That is why a microplastics result is only as meaningful as the sample, method, and particle-size range behind it.

"Microplastic-Free" Is Not a Simple Yes or No

Microplastic is a category, not one substance.

It includes particles made from different polymers, in different forms, across a wide range of sizes. A laboratory has to do more than find a speck. It has to determine whether that speck is plastic and whether it falls within the range the method was designed to analyze.

No analysis examines every possible particle at every possible size. It examines a defined sample under defined conditions and reports what the selected method can reliably identify.

That makes an absolute claim such as "microplastic-free" difficult to support. The more accurate question is narrower: what sizes were tested, by what method, and what was found within that range?

What µ-FTIR Is Looking For

One method used to analyze particles in water is micro-Fourier transform infrared spectroscopy, usually shortened to µ-FTIR.

Visual inspection can identify something that looks like a particle. µ-FTIR goes further by examining its infrared spectrum. That spectrum can be compared with reference materials to determine whether the particle's chemistry matches a known plastic polymer rather than a mineral, fiber, or other nonplastic material.

The instrument matters, but the method matters just as much. A named analytical standard explains the framework used to identify, size, count, and report the particles.

A conclusion without those details asks the reader to trust the result without seeing its boundaries.

Why Particle Size Changes the Answer

Every particle analysis has a lower size threshold. Below that point, the test does not make a claim.

If a report covers particles greater than 45 micrometers, its conclusion applies to particles above 45 µm. It does not automatically describe particles at 45 µm or below.

That number is a size boundary, not a concentration. It does not mean 45 micrograms per liter, and it does not describe how many particles could be present. It describes which particle dimensions were included in the reported result.

A microplastics result is only as broad as the sample, method, and particle-size threshold behind it.

Stating that threshold does not weaken a clean result. It defines the result precisely enough for someone else to understand and verify it.

What "None Detected" Actually Means

None detected means the laboratory identified no qualifying particles within the scope of that particular analysis.

It is a result tied to a sample, a method, and a size range. It is not a permanent description of every bottle or production lot, and it does not establish an absolute zero across sizes the method did not evaluate.

This is the same principle behind any non-detect result. The careful wording sounds narrower than a marketing phrase because it preserves the conditions of the test.

That precision is what makes the result useful.

How to Read a Microplastics Claim

When a brand mentions microplastics testing, look for five details:

• The independent laboratory that performed the analysis
• A report number or other traceable identifier
• The method and instrument used
• The particle-size threshold
• Wording that limits the result to the sample examined

"None detected above a stated size in the tested sample" is specific.

"Microplastic-free" leaves the method, size range, and sample limitation unresolved.

The strongest claim is not the loudest one. It is the one that lets the report speak in its own terms.

Where Unbelievable Water Fits

Report 25KA0156 from the Korea Institute of Analytical Science & Technology, or KIAST, records testing using a method per ISO 16094-2, with µ-FTIR on a LUMOS II instrument.

The reported result was:

No microplastic particles greater than 45 µm detected in the tested sample.

That is the language we use because it is the result the analysis supports. It does not make a claim about smaller particles, establish an absolute zero, or guarantee the same result for every production lot.

The laboratory, method, threshold, and other independent testing details are available on our Certifications page.

Good testing does not erase uncertainty. It defines where the evidence begins, where it ends, and what can honestly be said between those two points.

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Sources: KIAST Report No. 25KA0156; ISO 16094-2:2025, Water quality — Analysis of microplastic in water — Part 2.