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What to establish before ordering

Updated October 2026

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One: which method Two: which analyte Three: what preservative Four: what holding time Five: does it go in an autoclave Then volume, and headspace Ask who else uses the result References

Before buying anything, five answers decide the whole order, and all five come from the work rather than from a catalog.

One: which method

If the work is regulated or reported to anybody, a method applies and it may name the container. That is the first question and everything else is downstream of it. "We just need some bottles" is the answer that produces the wrong ones.

Two: which analyte

Table II is organized by parameter, and different parameters in the same sample can call for different containers. A site sampling for several things may need several container types from one visit, which is a purchasing fact people discover late.

Three: what preservative

Acid, base, thiosulfate or nothing, and whether it is added in the field or at the bench. A preservative changes what the container and especially the liner have to tolerate, and pre-preserved containers are a different product from empty ones.

Four: what holding time

Eight hours, 36 hours, 14 days, 28 days. It decides your logistics far more than your container choice, and a short holding time means a courier rather than a post.

Five: does it go in an autoclave

Sterilization by autoclave rules out most materials and some closures. If the container is reused or has to be sterile before use, that is a material specification and the Table II code for it is PA, a plastic made of a sterilizable material.

Then volume, and headspace

How much sample the method requires, plus whatever the preservative adds, and whether the method wants zero headspace. Volatiles in particular are collected with no bubble, which is a container and closure decision rather than a filling technique.

Ask who else uses the result

A number reported to a regulator, a customer or an internal log carries different requirements, and the most expensive version of this is discovering after sampling that the result had to be defensible. Settle it before the container is chosen.

References

40 CFR 136.3, Table II — Required Containers, Preservation Techniques, and Holding Times, which prescribes the container material, the preservation and the maximum holding time per parameter. Footnote 1 defines the codes: “P” is polyethylene, “FP” is fluoropolymer (PTFE), “G” is glass, “PA” is any plastic made of a sterilizable material. law.cornell.edu

Written from federal regulation, not from a bench. Where a method specifies a container, a preservative or a holding time, the method governs and nothing here overrides it. Read the method you are running rather than a summary of what methods generally say.