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INSTRUCTIONS How to store reagent tests?

What is the shelf life of a test kit?

All Chemical Safety kits use premium materials: high quality PE, heat purged glass and stainless steel. All this ensures the avarage shelf life of at least 1 year, with reagents continuing to work for much longer, but with diminished sensitivity. When reagents are not fresh you willl still be easily able to interpret results – especially if you keep an already confirmed sample for comparison.

  • Reagent tests have an avarage shelf life of 1 year, with the exception of Mandelin, which is best used before 12 months since purchase. Shelf life can be considerably extended by applying proper storate techniques.
  • TLC purity tests have avarage shelf life of at least 5 years, and doesn’t need to be cooled. Close the containers tightly because testing liquid can partially evaporate and spoil results.
  • Fentanyl test strips have shelf life of over 2 years and also do not need to be stored cooled.

What causes reagents to expire?

There are three phenomenons which contribute to reagent degradation:

  • Oxidation
  • Condensation
  • Precipitation

Oxidation happens over time and can be seen by reagents changing color over months of storage, also sygnalizing reduced sensitivity. To prolong shelf life follow the storage methods recommended below.

Condensation occurs when frozen reagents warm up and attract moisture from air. Moisture is terrible for reagents and should be avoided, therefore for normal use we recommend storing reagents in a fridge, not freezer. Ehrlich reagent is most sensitive to this issue.

Precipitation can be seen after prolonged storage when part of a reagent settles on the bottom after separating from the liquid. Always shake a reagent bottle before opening, especially Mandelin.


How to store reagents?

To prolong shelf life keep reagents standing up and in a cool, dark place. Fridge is best – cold temperatures help slow down reagent degradation.

Basic storage instructions:

  • Store reagent bottles standing up
  • Refrigerate reagents or store in a cool dark space
  • Only for prolonged storage (over 12 months) keep all reagents in a freezer (except Liebermann)
  • Always warm up to room temperature before use
Marquis reagent test kit

Marquis reagent test kit

How to check if a reagent is not expired?

  • Test any substance and compare color reactions with instructions. It’s easiest to use aspirin with Marquis reagent, which should slowly turn pink/red.
  • Keep a sample to compare later in case of doubt. If control sample reacts fine, it means the reagent still works.

Reagents presumptively indicate PRESENCE, but not PURITY or QUANTITY. To detect all ingredients and estimate potency it’s required to use an additional purity test kitA positive or negative test result does not indicate if the substance is safe. No substance is 100% safe.