Analytica Chimica Acta 803 (2013) 15–40 Contents lists available at ScienceDirect Analytica Chimica Acta j ourna l ho mepage: www.elsevier.com/locate/aca Review Flow injection analysis as a tool for enhancing oceanographic nutrient measurements—A review Paul J. Worsfold a , Robert Clough a , Maeve C. Lohan a , Philippe Monbet b , Peter S. Ellis c , Christophe R. Quétel d , Geerke H. Floor d , Ian D. McKelvie a,e,∗ a School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth, PL4 8AA, United Kingdom b Pole Mer Bretagne, CS 83809, 29238 Brest Cedex 3, France c Water Studies Centre, School of Chemistry, Monash University, Clayton, 3800, Australia d Institute for Reference Materials and Measurements, Joint Research Centre – European Commission, 111 Retieseweg, B-2440 Geel, Belgium e School of Chemistry, The University of Melbourne, Parkville, 3010, Australia h i g h l i g h t s • FIA and SIA techniques for nutrient determinations in marine waters are critically reviewed. • The advantages and suitability of FIA for underway and shipboard marine analysis are discussed. • Strategies for sensitivity improve- ment are considered. • Potential schlieren problems in FIA of marine samples and possible solu- tions proposed. • The importance of data quality and uncertainty estimation in trace anal- ysis are emphasised. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Received 27 April 2013 Received in revised form 13 June 2013 Accepted 15 June 2013 Available online 20 June 2013 Keywords: Marine waters Estuarine waters Macronutrients a b s t r a c t Macronutrient elements (C, N and P) and micronutrient elements (Fe, Co, Cu, Zn and Mn) are widely measured in their various physico-chemical forms in open ocean, shelf sea, coastal and estuarine waters. These measurements help to elucidate the biogeochemical cycling of these elements in marine waters and highlight the ecological and socio-economic importance of the oceans. Due to the dynamic nature of marine waters in terms of chemical, biological and physical processes, it is advantageous to make these measurements in situ and in this regard flow injection analysis (FIA) provides a suitable shipboard plat- form. This review, therefore, discusses the role of FIA in the determination of macro- and micro-nutrient elements, with an emphasis on manifold design and detection strategies for the reliable shipboard deter- mination of specific nutrient species. The application of various FIA manifolds to oceanographic nutrient Abbreviations: 8HQ-MAF, 8-quinolinol immobilised on silica gel, metal alkoxide fluoride glass; C4 D, contactless capacitively coupled conductivity detector; CL, chemi- luminescence; CRM, certified reference material; CTAB, cetyltrimethylammonium bromide; DIC, dissolved inorganic carbon; DDAB, didodecyldimethylammonium bromide; DIC, dissolved inorganic carbon (also called “total carbonate”); DOC, dissolved organic carbon; DOP, dissolved organic phosphorus; DRP, dissolved reactive phosphorus; FIA, flow injection analysis; GD, gas diffusion; GF-AAS, graphite furnace atomic absorption spectrophotometry; GUM, guide to the expression of uncertainty in measurements; HNLC, high-nutrient, low-chlorophyll regions; HTCO, high temperature catalytic oxidation; ICP-SFMS, inductively coupled plasmas-sector field mass spectrometry; id, inside diameter; ID, isotope dilution; IDA, iminodiacetate resin; LOC, Lab-on-Chip; LOD, limit of detection; LWCC, liquid waveguide capillary cell; MRFC, multi-reflection flow cell; NOx, nitrate + nitrite; NTA, nitriloacetic acid; od, outside diameter; OPA, orthophthaldialdehyde; pCO 2 , partial pressure of carbon dioxide; PON, particulate organic nitrogen; PSII, Photosystem II; RI, refractive index; RM, reference material; ROV, remotely operated vehicle; RSD, relative standard deviation; REU, relative expanded uncertainty; S, salinity; SAFe, sampling and analysis of iron program; SCFA, segmented continuous flow analysis; SOD, superoxide dismutase; SP, spectrophotometry; ∑ CO2, dissolved inor- ganic carbon (also called “total carbonate”); TA, total alkalinity; TC, total carbon; TCNQ, 7,7,8,8-tetracyanoquinodimethane; TCO 2 , dissolved inorganic carbon (also called “total carbonate”); TDN, total dissolved nitrogen; TDP, total dissolved phosphorus; TIC, total inorganic carbon; TOC, total organic carbon; TN, total nitrogen; TP, total phosphorus; TPN, total particulate nitrogen. ∗ Corresponding author. E-mail address: ian.mckelvie@gmx.com (I.D. McKelvie). 0003-2670/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.aca.2013.06.015