Lachat nutrient analyzer

General Info

The MSRF performs dissolved nutrient analysis on aqueous samples using a QuickChem QC8500 automated ion analyzer made by Lachat.

We are currently equipped to analyze five nutrients: ammonium, phosphate, silicate, nitrite and total nitrite+nitrate. The following table lists the methods used for each nutrient as well as our minimum detection limits (MDL) in seawater.

Nutrient Method Concentration range (uM) MDL (uM)
ammonium Method 31-107-06-1-B 0 – 40 0.20
phosphate Method 31-115-01-1-H 0 – 10 0.05
silicate Method 31-114-27-1-A 0 – 100 0.10
nitrite Method 31-107-05-1-A 0 – 20 0.30
nitrite+nitrate Method 31-107-04-1-A 0 – 20 0.30

An example at the MSRF

The figures below illustrate a nutrient profile obtained from a CTD cast conducted on board the RV Endeavor in June of 2016. The cast was carried out at the continental shelf break (approximately 39°46.209’N and 70°51.436’W) as part of a study examining carbon and particle fluxes down the water column.