Programmable flow injection for shipboard nutrient analysis: Method validation from the International Nutrient Intercomparison Voyage.

Abstract

Expanding nutrient data availability in remote locations and during small-scale events is most feasible through in-situ, autonomous sampling method. However, traditional flow-based analyzers, which are actively used in current oceanographic research cruises, face laminations, as they cannot be easily scaled down or made autonomous. Their large waste generation and dependency on user intervention present significant obstacles to technological advancement. The lack of alternative streamlined methods complicates sampling strategies and introduces logistical challenges. In these contexts, there is a pressing need for novel, yet straightforward instrumentation to gather data with reliably and at high frequencies. Programmable flow injection (pFI) represents a new generation of automated flow-based techniques aimed at improving the spatial-temporal distribution of nutrient data through rapid shipboard determinations. This work introduces innovations to the pFI method, including automated creation of a five-point standard curve using a single high concentrated standard solution, applying this to the oceanographic research cruises, including the International Nutrient Intercomparison Voyage (INIV) and the Hawaiian Ocean Time-series (HOT). These results yielded consistent and agreeable data with standard nutrient methods, indicating a promising outlook for integration of this new technology for regular nutrient measurements.