1) Do not apply silicone grease, adhesives, or sealant to the tops of vials. These materials clog the autosampler needle. The process of removing these sealants increases the risk of losing your gas samples due to dislodged septa.

2) Please contact the SIF prior to the collection, preparation, and/or shipment of water samples for bacteria denitfication assay. Failure to do so may result in delays in excess of 6 months, unsuccessful analysis, and loss of your water samples.

3) Highly acidic and highly alkaline samples can affect the denitrifying bacteria. Preservatives and poisons that halt biological activity can also affect the denitrifying bacteria. Instead, we recommend filtering samples and freezing immediately.

4) Accurate nitrate concentrations are required for all samples. Please specify if your concentration is NO3 vs. NO3-N, μM vs. mg/L, etc.