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We recommend the following preservation procedures, holding times and conditions when submitting solid samples for National Measurement Institute (NMI) testing. Please treat these recommendations as a guide only.

TestContainerSample sizePreservation procedure (treatment after collection until arrival at NMI)Holding time (maximum time from collection until analysis)Reference
Bromideplastic or glass20 gair dry or field moist28 daysNEPM
Carbon (TOC)glass20 gair dry or field moist28 daysNEPM
Chlorideplastic or glass20 gair dry or field moist28 daysNEPM
Conductivityplastic or glass20 gair dry or field moist7 daysNEPM
Cyanidesplastic or glass20 gfield moist14 daysNEPM
Dioxinsglass100 gcool to <4 °C1 year until (1 after) extractionUS EPA 1613
Fluorideplastic or glass20 gair dry or field moist28 daysNEPM
Herbicidesglass20 g or 1 x 125 mLcool to <4 °C14 daysUS EPA SW-846
Hexavalent chromiumplastic20 gfield moist28 daysNEPM
Mercuryplastic20 gfield moist28 daysNEPM
Metalsplastic or glass20 gair dry or field moist6 monthsNEPM
Moistureplastic or glass20 gfield moist14 daysNEPM
Organochlorine pesticidesglass20 g or 1 x 125 mLcool to <4 °C14 days until extraction, 40 days until analysisUS EPA SW-846
Organophosphorus pesticidesglass20 g or 1 x 125 mLcool to <4 °C14 days until extraction, 40 days until analysisUS EPA SW-846
Organotins (tributyl tin – TBT)glass20 g or 1 x 125 mLcool to <4 °C14 daysNAGD
PAHsglass20 g or 1 x 125 mLcool to <4 °C14 days until extraction, 40 days until analysisUS EPA SW-846
PBDEsglass100 gcool to <4 °C1 year until (1 after) extractionUS EPA 1614
PCBs (dioxin-like)glass100 gcool to <4 °C1 year until (1 after) extractionUS EPA 1668
PCBsglass20 g or 1 x 125 mLcool to <4 °C14 days until extraction, 40 days until analysisUS EPA SW-846
PFAS (including PFOS and PFOA)HDPE250 mL jarcool to <4 °C60 days until (30 days after) extractionUS EPA 821-R-11-007
pHplastic or glass20 gair dry or field moist7 daysNEPM
Phenolsglass20 g or 1 x 125 mL jarcool to <4 °C14 days until extraction, 40 days until analysisUS EPA SW-846
Sulphateplastic or glass20 gair dry or field moist28 daysNEPM
SVOC (includes pesticides, herbicides, chlorinated hydrocarbons)glass20 g or 1 x 125 mLcool to <4 °C14 days until extraction, 40 days until analysisUS EPA SW-846
TCLPplastic or glass50 gas per analyteas per analyteUS EPA 1311
TRH (C6–C10)/BTEXglass20 g or 1 x 125 mLcool to <4 °C, minimise headspace14 daysUS EPA SW-846
TRH (C10–C40)glass20 g or 1 x 125 mLcool to <4 °C14 daysUS EPA SW-846
VOCs (includes halogenated aliphatics and aromatics, monocyclic aromatics, alcohols)glass20 g or 1 x 125 mLcool to <4 °C, minimise headspace14 days (7 days for vinyl chloride and styrene)US EPA SW-846

References 

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Last updated: 13 September 2019

Content ID: 64629