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Home > Ag Chemicals & Fertilizers > Spills & Safety > Incident Response Unit > Guidance Documents > Groundwater Sampling Guidance (GD12) > Containers Preservation Techniques and Holding Times - Attachment 3

Ground Water Sampling Guidance (GD12c)


Attachment 3 - Containers, Preservation Techniques and Holding Times

Parameter Container Preservative 1  Maximum Holding Time 2 
Nitrate + Nitrite 100 ml. poly cool 4°C, H2SO4 to pH<2 28 days
Ammonia 100 ml. poly cool 4°C, H2SO4 to pH<2 record pH and temp. at time of collection 28 days
Base Neutral Pesticides (MDA List 1) 1000 ml. amber glass cool 4°C follow applicable method holding times
Acid Pesticides (MDA List 2) 1000 ml. amber glass cool 4°C, H2SO4 to pH<2 follow applicable method holding times
Carbamates (MDA List 3) 1000 ml. amber glass cool 4°C, 5 mls. of 1% phosphoric acid follow applicable method holding times
Pentachlorophenol 1000 ml. amber glass cool 4°C, H2SO4 to pH<2 7 days until extraction

Notes:

  • 1Sample preservation should be performed immediately upon sample collection.
  • 2Samples should be analyzed as soon as possible after collection. The times listed are the maximum holding times that samples may be held before analysis and still be considered valid. 

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