Containers

Closures

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What is here A sample container wants a plain cap Which makes 346 of 409 the right distribution The liner is the specification Phenolic where the liner has to hold Dome lids for the jars For dissolved oxygen the closure is named Necks to standardise on Carry spares into the field And check the thread before every fill References

346 continuous thread. For a sample container that is the right answer.

What is here

346 continuous thread, 27 dome lids, 14 phenolic, 11 liners and sealing discs, 6 specialty and 2 lug and twist.

A sample container wants a plain cap

No pump, no dropper, no dispensing mechanism. The container is opened once to fill and once to analyze, and anything with moving parts is a surface the sample can touch.

Which makes 346 of 409 the right distribution

Unusually for this catalog, the dominant closure type is the correct one for the craft rather than a compromise.

The liner is the specification

11 liners and sealing discs. It is a polymer surface in contact with the sample, with the same adsorption question as the wall, and it is the part nobody writes on an order.

Phenolic where the liner has to hold

14 of them. For an acid-preserved sample or an organic parameter, the traditional resistant closure.

Dome lids for the jars

27, for soil and botanical samples. Wide, quick, and openable with cold or gloved hands, which is the real field condition.

For dissolved oxygen the closure is named

"G, Bottle and top." Nothing on this shelf is sold as a dissolved oxygen bottle with its matched top, and that is a specific absence worth stating.

Necks to standardise on

72 containers at 89-400 and 42 at 70-400 for the jars; 31 at 20-400 and 26 at 20-410 for the small bottles. Two of each covers a kit.

Carry spares into the field

A dropped cap at a stream bank is a sample you cannot close. Spare closures weigh nothing and they are the difference between a lost site and a full set.

And check the thread before every fill

Grit, leaf fragments and sediment on a thread are the commonest reason a cooler arrives wet. Wipe it, then close it.

References

The Davis Pack Supply catalog, measured 19 October 2026. The field sampling shelf is 768 rows: 359 containers and 409 closures. 5 mL to 950 mL with a median of 118; 124 containers at 60 mL or under, 211 at 120 or under, 317 at 500 or under, and nothing above a litre. 146 PET, 108 glass, 92 HDPE, 13 PP, no LDPE and no fluoropolymer. 194 jars, 163 bottles, 2 tubes. 103 clear, 82 white, 52 amber, 34 natural. Closures: 346 continuous thread, 27 dome lids, 14 phenolic, 11 liners and sealing discs, 6 specialty.

40 CFR 136.3, Table II, selected rows. Oil and grease: G, cool to 6 degrees C or below and acidify to pH below 2, 28 days. Phenols: G, 28 days. Phosphorus (elemental): G, 48 hours. Fluoride: P, no preservation required, 28 days. Silica: P or Quartz, 28 days. Boron: P, FP, or Quartz, nitric acid to pH below 2, 6 months. Cryptosporidium and Giardia: LDPE with field filtration, 1 to 10 degrees C, 96 hours. Dissolved oxygen by probe: G, bottle and top, analyze within 15 minutes. Chlorine, total residual: P, G, analyze within 15 minutes. pH: P, FP, G, analyze within 15 minutes. Coliform and E. coli: PA, G, 8 hours. Hardness: P, FP, G, 6 months. Nitrate: P, FP, G, 48 hours. ecfr.gov

Written from 40 CFR 136.3 Table II and from the catalog as it stood on 19 October 2026. Part 136 governs Clean Water Act compliance monitoring; it is used here for everything else as the best available statement of what a container does to a water sample, not as a rule that binds a student with a creek. Nothing on this shelf is sold precleaned or certified for regulated sampling, and no preservation chemistry is given, because that belongs to the laboratory running the analysis.