Shipboard Fluorometric Flow Analyzer for High-Resolution Underway Measurement of Ammonium in Seawater

Amornthammarong, Natchanon; Zhang, Jiazhong

doi:10.1021/ac701942f

Cited by 64 publications

(40 citation statements)

References 35 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other workers have reported negligible salt effects, up to 2.2% change of the measured signal (Aminot et al, 2001;Amornthammarong and Zhang, 2008), whilst others have reported higher salinity effects on ammonium analysis, particularly when using Milli-Q water for the preparation of standards (Watson et al, 2004;Taylor et al, 2007). In this work, two experiments have been conducted: First, a wide range of ammonium standards were prepared (5 nM, 50 nM, 500 nM, 1 μM, 5 μM and 25 μM) using ASW of 35 salinity and have been compared with the same standards made with Milli-Q water (Fig.…”

Section: Salinitymentioning

confidence: 87%

“…The negligible interferences were due to the addition of sulfite in the reagent. In addition, the OPA-sulfite-formaldehyde method by Amornthammarong et al (2008) demonstrated the suppression of amine and amino acid interferences for samples prepared with Milli-Q in the laboratory.…”

Section: Amino Acid and Amine Interferencesmentioning

confidence: 99%

“…The kinetics of the chemical reaction of the OPA/Sulfite/ NH 4 + has also been widely reported in the literature under various pH values, buffer compositions, temperature and salinity conditions and the effect on system performance was established (Goyal et al, 1988;Genfa and Dasgupta 1989;Aminot and Kérouel 2006;Amornthammarong and Zhang, 2008). This method is not without problems and challenges.…”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

A high-resolution analyser for the measurement of ammonium in oligotrophic seawater

et al. 2011

View full text Add to dashboard Cite

In this work, we describe a high-resolution fluorometric shipboard analyser and an improved method to determine NH 4 + in oligotrophic seawater. The limit of detection is <5 nM, calculated with 95% confidence level using the weighted regression line applied to the standard addition method using real samples prepared with low nutrient seawater from the Atlantic. The results are summarised and cross-compared with spiked artificial seawater (ASW) and spiked Milli-Q water samples. The analyser has a precision of ±1-4% with a high performance over a wide range from 5 nM to 25 μM. The methodology of NH 4 + analysis is based on the fluorescent product formed between o-pthaldialdehyde and NH 4 + in the presence of sulfite. Due to the high resolution of the developed system, we were able to study in depth the sensitivity of the method to salinity, amines, amino acids and potential interferences from particles/algae. The method was found to be sensitive to salinity variations, reducing the signal by up to 85% at 5 nM; this effect decreased at higher concentrations of ammonium. It was noted that the interference from amines at low concentrations was negligible; however, at either high amino acid or high amine concentrations, the signal was depressed. To test for the effect of particles on the system, the system was tested with samples containing phytoplankton (Dunaliella primolecta) cells at different concentrations prepared with ASW to simulate the effect of a phytoplankton bloom. This experiment assessed the potential impact of both particles and other potential fluorescence interferences from cells and/or ammonium leaching from cells. This experiment showed that a phytoplankton bloom could potentially have an impact of up to 12% on the signal of interest. Thus, we propose that this method is suitable for oligotrophic environments rather than coastal and eutrophic environments. The reagent was found to be stable for 17 days and standards of 1 μM were stable for 6 days under laboratory conditions. The developed analyser was successfully demonstrated in the North Atlantic Ocean, in an area of oligotrophic, low NH 4 + oceanic waters.

show abstract

Section: Salinitymentioning

confidence: 87%

Section: Amino Acid and Amine Interferencesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

A high-resolution analyser for the measurement of ammonium in oligotrophic seawater

et al. 2011

View full text Add to dashboard Cite

show abstract

“…On-line scrubbing into an aqueous collector and an appropriate on-line aqueous phase fluorogenic reaction are used, e.g., for H 2 S (135, 136), HCHO (137,138), NH 3 (139), and NO 2 (140). Similar measurements have been made for NH 4 + in seawater (141)(142)(143) or HCHO in foods (144), etc. In many cases, multiple LEDs, with or without interference filters and/or ball lenses for focusing, can be arranged around the flow tube, and an integral photodiode-operational amplifier detector, with or without additional amplification, provides sufficient sensitivity for the end application.…”

Section: Macroscale Flow-through Fluorescence Detectors and Sensorsmentioning

confidence: 99%

Light-Emitting Diodes for Analytical Chemistry

Macka

Piasecki

Dasgupta

2014

Annual Rev. Anal. Chem.

113

View full text Add to dashboard Cite

Light-emitting diodes (LEDs) are playing increasingly important roles in analytical chemistry, from the final analysis stage to photoreactors for analyte conversion to actual fabrication of and incorporation in microdevices for analytical use. The extremely fast turn-on/off rates of LEDs have made possible simple approaches to fluorescence lifetime measurement. Although they are increasingly being used as detectors, their wavelength selectivity as detectors has rarely been exploited. From their first proposed use for absorbance measurement in 1970, LEDs have been used in analytical chemistry in too many ways to make a comprehensive review possible. Hence, we critically review here the more recent literature on their use in optical detection and measurement systems. Cloudy as our crystal ball may be, we express our views on the future applications of LEDs in analytical chemistry: The horizon will certainly become wider as LEDs in the deep UV with sufficient intensity become available.

show abstract

“…In the surface seawater of the South China Sea (SCS), ammonium is present in dozens of nanomolar concentrations (Zhu et al 2013). In order to measure such low levels of ammonium in the oceanic waters, different sensitive methods have been developed and applied (Amornthammarong and Zhang 2008;Plant et al 2009;Bey et al 2011;Zhu et al 2014;Hashihama et al 2015;Kodama et al 2015). However, there are several discrepancies in the application of these methods, since they require measurements of nanomolar concentrations of ammonium (Plant et al 2009).…”

mentioning

confidence: 99%

A novel ammonium‐free seawater preparation method for determination of trace quantities of ammonium in seawater

Zhu

Yuan

Chen

et al. 2017

Limnology & Ocean Methods

View full text Add to dashboard Cite

A novel method for preparation of ammonium-free seawater, which is used as a carrier solution and matrix for standard solutions, was designed. These standard solutions are used for calibration curve in flow analysis to detect trace quantities of ammonium in seawater. The system, which consisted of only a peristaltic pump and a hydrophilic-lipophilic balance (HLB) cartridge, was simple, convenient, and easy to operate. The original seawater used in the method could be collected from the coastal regions. And appropriate quantities of ophthaldialdehyde (OPA) and sulfite solution were added to the original seawater (The molar proportions of ammonium : OPA : sulfite were 1 : 200 : 80). After allowing it to set for more than 16 h, the seawater was pumped through the HLB cartridge. The reaction product of ammonium (present in the matrix), OPA and sulfite was retained by the HLB column and the solution coming out of the cartridge was ammonium-free seawater. The ammonium in the original seawater was efficiently removed and also its concentration in the ammonium-free seawater prepared by this method was much lower than that of the seawater collected from the surface of the South China Sea. The difference in the salinity of the seawater before and after the process was negligible, and also the pH was slightly increased. Moreover, ammonium-free seawater could be prepared whenever required, and contamination due to transportation and storage could be prevented.

show abstract

Shipboard Fluorometric Flow Analyzer for High-Resolution Underway Measurement of Ammonium in Seawater

Cited by 64 publications

References 35 publications

A high-resolution analyser for the measurement of ammonium in oligotrophic seawater

A high-resolution analyser for the measurement of ammonium in oligotrophic seawater

Light-Emitting Diodes for Analytical Chemistry

A novel ammonium‐free seawater preparation method for determination of trace quantities of ammonium in seawater

Contact Info

Product

Resources

About