Ion chromatography for determination of nitrite and nitrate in seawater using monolithic ODS columns

Ito, Kohzo; Takayama, Yohichi; Makabe, Nobuyuki; Mitsui, Ryo; Hirokawa, Takatsugu

doi:10.1016/j.chroma.2005.05.073

Cited by 94 publications

(44 citation statements)

References 21 publications

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“…However, upon the determination of nitrate concentrations lower than 1 μmol/l, the peak tail of bromide had the potential to interfere with the nitrate peak. A decrease in the eluent concentration enhanced the separation between these anions, 21 but the detection limit also became higher. For better separation of these inorganic anions, variations of the cations were examined on the counter ions in the eluent.…”

Section: Effect Of Counter Cations In the Eluentmentioning

confidence: 99%

“…18 Problems with the IC method can be ascribed to the poor fit of the ion exchanger used in conventional ion chromatographic systems in circumstances of high-concentration eluents. Ito et al [19][20][21] coated an ODS bed with long-chained tetraalkylammonium to increase the ion-exchange capacity for direct injection and the determination of nitrate and other anions in seawater. Nakamura et al 22,23 successfully used a highcapacity ion exchanger (SAX, Tosoh) and sodium chloride eluent to measure the total nitrogen content in seawater as nitrate after oxidation by peroxybisulfate.…”

Section: Introductionmentioning

confidence: 99%

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Onboard Determination of Submicromolar Nitrate in Seawater by Anion-Exchange Chromatography with Lithium Chloride Eluent

2006

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Nitrogen is an essential element for phytoplankton growth in aquatic environments. Nitrate is the main nutrient supporting this production in the open ocean, and the supply of nitrate often controls primary production in oligotrophic areas. Excluding the high-latitude and eastern equatorial regions of the Pacific, the surface waters of the North and South Pacific Ocean from about 40˚ N to 40˚ S are relatively depleted in nitrate. In the North Pacific subtropical gyre, nitrate concentrations are typically below 10 nmol/l.1 To understand the nitrogen cycles in the open ocean ecosystem, a sensitive analytical method to determine the nanomolar levels of nitrate in seawater is essential.The standard method of nitrate determination in seawater is based on a flow-injection technique with spectrophotometric detection. [2][3][4] In this method, nitrate is first reduced to nitrite in a copperized cadmium column.Nitrite is coupled with sulfanilamide to form a diazonium cation. This diazonium reacts with N-1-naphtylethylenediamine dihydrochloride, forming a purple azo dye whose absorbance is measured at 550 nm. Next, the nitrite is measured independently according to the same method without reduction. Nitrate is then calculated from the difference in the concentration between [nitrate + nitrite] and nitrite. This method can be conventionally applied to the determination of nitrate and nitrite on board; its detection limit is about 50 nmol/l as [nitrate + nitrite].A more sensitive method of nitrate analysis has been developed by utilizing the chemiluminescence of nitrogen monoxide. [5][6][7] In this method, both nitrate and nitrite are reduced to nitrous oxide in a highly acidic solution of sulfuric acid containing iron(II) ammonium sulfate and ammonium molybdate. Nitrous oxide in the solution is carried to a drying tube and reacts with ozone, resulting in chemiluminescence. The detection limit is around 2 nmol/l. This measurement method also requires nitrate reduction to nitrite. By this method, Cavender-Bares et al. 8 measured 2 to 10 nmol/l concentrations of [nitrate + nitrite] in surface seawater that were below the detection limit of the standard method using azo dye formation. They revealed the vertical gradients of [nitrate + nitrite] in the North Atlantic Ocean.As a simple method, direct UV determination 2,4,9 has also been examined, but often encounters interference by bromide or organic compounds, such as humic substances, which also have UV absorbance in a wavelength range similar to that of nitrate. Capillary electrophoresis 10,11 is very useful because it gives high efficiency in the separation of analytes, and enables rapid analysis and the direct injection of seawater. However, the small injection volume and short path length of the detector results in a poor detection limit for nitrate and nitrite.Ion chromatography (IC) 12 is advantageous in the determination of nitrite and nitrate because these anions can be separated from other ions, such as bromide and organic substances. However, with highly ionic mat...

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Section: Effect Of Counter Cations In the Eluentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Onboard Determination of Submicromolar Nitrate in Seawater by Anion-Exchange Chromatography with Lithium Chloride Eluent

2006

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“…The limits of detection (S/N = 3) for nitrite and nitrate were 0.8 μg/L and 1.6 µg/L, respectively [33]. Typical chromatogram of a sample is in the original publication presented in Figure 3. …”

Section: Nitrite and Nitratementioning

confidence: 99%

Ion Chromatographic Analyses of Sea Waters, Brines and Related Samples

Gros

2013

Water

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This review focuses on the ion chromatographic methods for the analyses of natural waters with high ionic strength. At the beginning a natural diversity in ionic composition of waters is highlighted and terminology clarified. In continuation a brief overview of other review articles of potential interest is given. A review of ion chromatographic methods is organized in four sections. The first section comprises articles focused on the determination of ionic composition of water samples as completely as possible. The sections-Selected Anions, Selected Cations and Metals-follow. The most essential experimental conditions used in different methods are summarized in tables for a rapid comparison. Techniques encountered in the reviewed articles comprise: direct determinations of ions in untreated samples with ion-or ion-exclusion chromatography, or electrostatic ion chromatography; matrix elimination with column-switching; pre-concentration with a chelation ion chromatography and purge-and-trap pre-concentration. Different detection methods were used: non-suppressed conductometric or suppressed conductometric, direct spectrometric or spectrometric after a post-column derivetization, and inductively coupled plasma in combination with optical emission or mass spectrometry.Keywords: ion chromatography; sea water; brine; mineral water; anions; cations; metals Natural Diversity of WatersWe restrict the scope of this review and choose to focus on natural waters with high ionic strength in which concentrations of ions extend over several orders of magnitude and therefore these waters present a special challenge for ion chromatographic (IC) analysis, especially if major and minor ions OPEN ACCESS

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“…The feasibility of flow-injection techniques with spectroscopic detection for remote deployment to measure multiple variables with high resolution has been described recently (Manrahan et al 2002). Further improvement and application of these systems in field observations will greatly advance our Although several methods for nitrate and nitrite determinations in seawater have been reported, including spectrophotometry, chemilumenesence, electrophoresis, florescence spectroscopy, high pressure liquid chromatography (HPLC), and ion chromatography (Garside 1982;Kieber and Seaton 1995;Daniel et al 1995;Hansen and Koroleff 1999;Okemgbo et al 1999;Masserini and Fanning 2000;Manrahan et al 2002;Thouron et al 2003;Ito et al 2005), the colorimetric method with cadmium reduction remains the most popular technique for nitrate determinations in natural waters (Moorcroft et al 2001). To increase sensitivity, long-path flow cells have been successfully incorporated into conventional spectrophotometric methods for nitrate and nitrite measurements at nanomolar level (Yao et al 1998;Zhang 2000).…”

Section: Introductionmentioning

confidence: 99%

Underway monitoring of nanomolar nitrate plus nitrite and phosphate in oligotrophic seawater

Hansell

Zhang

2008

Limnology & Ocean Methods

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To study nutrient dynamics and cycling in oligotrophic open ocean environments, continuous measurements of nanomolar nitrate, nitrite, and phosphate are valuable. However, such studies are usually impeded by the detection limits of conventional nutrient-sensors and analyzers. Here, we developed a shipboard deployable underway system for simultaneously monitoring nitrate plus nitrite and phosphate at nanomolar concentrations by the coupling of an optimized flow injection analytical system with two long-path liquid waveguide capillary cells (LWCC). The detection limits are ~2 nM for nitrate plus nitrite and ~1.5 nM for phosphate, respectively. Results from realtime surveys of waters over the west Florida continental shelf and the oligotrophic Sargasso Sea are presented. This system has also been successfully used to analyze more than 1000 discrete seawater samples manually during 2 cruises in the North Atlantic.

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Ion chromatography for determination of nitrite and nitrate in seawater using monolithic ODS columns

Cited by 94 publications

References 21 publications

Onboard Determination of Submicromolar Nitrate in Seawater by Anion-Exchange Chromatography with Lithium Chloride Eluent

Onboard Determination of Submicromolar Nitrate in Seawater by Anion-Exchange Chromatography with Lithium Chloride Eluent

Ion Chromatographic Analyses of Sea Waters, Brines and Related Samples

Underway monitoring of nanomolar nitrate plus nitrite and phosphate in oligotrophic seawater

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