Journal ArticleDOI
Polarographic methods for measuring uncomplexed sulphide ions in natural waters
W. Davison,C.D. Gabbutt +1 more
TLDR
Differential pulse polarography has been shown to be capable of measuring sulphide directly in untreated natural water samples as mentioned in this paper, which is the preferred technique for direct colorimetry and is in good agreement with direct colourimetry, and can be used to assess the applicability of a particular calibration technique.About:
This article is published in Journal of Electroanalytical Chemistry.The article was published on 1979-06-08. It has received 29 citations till now. The article focuses on the topics: Polarography.read more
Citations
More filters
Journal ArticleDOI
Polarographic analysis of sulfur species in marine porewaters1
TL;DR: A scheme to determine the major sulfur species found in marine porewaters is described in this paper, where it is possible to measure thiosulfate, sulfite, bisulfide, and polysulfide ions at a mercury electrode.
Journal ArticleDOI
Sulfur speciation and sulfide oxidation in the water column of the Black Sea
Abstract: We have applied sulfur speciation techniques to understand the chemistry and cycling of sulfur in Black Sea waters. The only reduced dissolved inorganic sulfur species detected (above the low minimum detection limits of the voltammetric methods employed) in the water column was hydrogen sulfide. The maximum concentration of sulfide (423 μ M) is similar to previous reports. Using a cathodic stripping square wave voltammetry (CSSWV) method for nanomolar levels of sulfide, we determined the precise boundary between the “free” hydrogen sulfide (sulfidic) zone and the upper (oxic/suboxic) water column at the two stations studied. This boundary has apparently moved up by about 50 m in the past 20 years. Our results help demonstrate three chemically distinct zones of water in the central basin of the Black Sea: (1) the oxic [0–65 m], (2) the anoxic/nonsulfidic [65–100 m] and (3) the sulfidic [>100 m]. Sulfide bound to metals (“complexed” sulfide) is observed in both the oxic and anoxic/nonsulfidic zones of the water column. This supports previous studies on metal sulfide forms. From the electrochemical data, it is possible to estimate the strength of the complexation of sulfide to metals (log K = 10 to 11). Thiosulfate and sulfite were below our minimum detectable limit (MDL) of 50 nM using CSSWV. Elemental sulfur (MDL 5 nM) was detected below the onset of the hydrogen sulfide zone (90–100 m) with a maximum of 30–60 nM near 120 m. The sulfur speciation results for the Black Sea are lower by one order of magnitude or more than other marine systems such as the Cariaco Trench and salt marshes. New HPLC techniques were applied to detect thiols at submicromolar levels. The presence of thiols (2-mercaptoethylamine, 2-mercaptoethanol, N -acetylcysteine and glutathione) is correlated with the remineralization of organic matter at the oxic and anoxic/nonsulfidic interface. Water samples collected from the upper 50 m of the sulfidic zone showed significant sulfide oxidation on storage onboard ship even though they were filtered (0.2 μ m) and handled to exclude oxygen contamination. Chemical additives such as formaldehyde, glutaraldehyde, hydroxylamine and ascorbic acid prevented or retarded the sulfide loss. Thiosulfate and azide did not inhibit sulfide loss. These studies suggest an anaerobic chemical oxidation of sulfide rather than a biological oxidation on stored and filtered samples.
Journal ArticleDOI
Metal–sulfide complexation in seawater
TL;DR: In this paper, the conditional stability constants of metal-sulfide complexes were determined in pH 8 seawater at various salinities, by flow-analysis with detection by cathodic stripping voltammetry (FA-CSV).
Journal ArticleDOI
Rate of formation and dissolution of mercury sulfide nanoparticles: The dual role of natural organic matter
TL;DR: In this article, the effect of dissolved organic matter (DOM) isolated from natural waters on reactions between mercury(II) (Hg) and sulfide (S(-II)) to form HgS (s) nanoparticles across a range of Hg and S(-II) concentrations was investigated.
Journal ArticleDOI
Speciation analysis — why and how?
TL;DR: The different aspects of speciation analysis are reviewed in this paper, where species-specific instrumental techniques as well as various speciation schemes are considered for the determination of species of metals and metalloids, including organometallic compounds.
References
More filters
Journal ArticleDOI
Defining the electroanalytically measured species in a natural water sample
TL;DR: In this paper, the possible definition of chemical species disolved in natural waters is discussed using electroanalytical techniques, and the time of measurement is identified as the critical parameter for determining which species in solution will be measured when using transient techniques.
Journal ArticleDOI
Modulated polarographic and voltammetric techniques in the study of natural water chemistry
W. Davison,M. Whitfield +1 more
TL;DR: In this paper, the most productive field of application of modulated polarographic and voltammetric methods is in determining the chemical speciation of electroactive components in natural waters.
Journal ArticleDOI
Ferrous iron‐sulfide interactions in anoxic hypolimnetic waters
W. Davison,S. I. Heaney +1 more
TL;DR: In this paper, seasonal polarographic measurements of sulfide and ferrous iron concentrations in the hypolimnion of a thermally stratified lake show that the inorganic chemistry in the waters nearest the sediment is dominated by ferrous sulfide precipitation.