Determination Of Sulfide Ions Research Articles

Facile preparation of dihydrolipoic acid-stabilized red-emitting silver nanoclusters as a sensitive fluorometric probe for sulfide ions detection

In this work, we report a smartphone-integrated paper-based sensor for the determination of sulfide ions (S2−) using water-soluble dihydrolipoic acid stabilized silver nanoclusters (DHLA-AgNCs) as a nanoprobe. The optical properties of red emitting fluorescent DHLA-AgNCs was confirmed by UV–visible, steady state flourometric spectroscopic studies. The HR-TEM analysis revealed that the morphology of DHLA-AgNCs was quasi spherical with a grain size of ∼ 5.2 nm. The DHLA-AgNCs exhibited bright red luminescence with strong emission band centered at 650 nm upon the excitation at 420 nm. The excellent fluorescence property of DHLA-AgNCs was further utilized for fluorometric determination of S2− ions. The DHLA-AgNCs can be effectively quenched by increasing concentration of S2− ions owing to the formation of Ag2S complex. The DHLA-AgNCs probe could detect S2− ions preferentially even in the presence of other possible interfering anions with a limit of detection of 32.71 nM. In addition, the proposed technique was effectively used to detect S2− ions in environmental water samples such as tap and drinking water. The detect S2− ions detection was assay and showed good agree compared with the conventional methylene blue approach and showed comparable results. Moreover, a smartphone-paper-based detection assay was developed using the DHLA-AgNCs probe for highly selective and sensitive determination of S2− ions.

Development, characterization, and applications of a portable analyzer for continuous monitoring of H2S in gas streams

A bench-scale analyzer for continuous monitoring of H2S in gas streams was previously described (2012 Sens. Actuators B 162 377–83). The analyzer was based on the exothermic reaction between the scrubbed H2S, in alkaline solution, with hydrogen peroxide. The analyzer offers several advantages but suffers from a relatively slow response time (i.e. 7 min) and a relatively low sensitivity (limit of detection = 100 ppm). In the present work, a substantially improved detector design and direct mixing of the gas with the liquid reagents are described. The improved detector, in the form of a coiled thin-walled stainless-steel (SS) tube also acts as a compartment for direct gas absorption and reaction with sodium hydroxide and hydrogen peroxide reagents, which eliminates the need for a gas scrubber based on microporous hollow fiber membranes (HFMs). The average temperature of the SS coil was measured by three thermocouples attached to the outer surface of the coil with thermally conductive epoxy. The improved detector design and the simplified scheme proved very successful in achieving six times faster response (i.e. 70 s) and ten times more sensitive response (i.e. 10 ppm) in the gas stream and improved repeatability (coefficient of variation = 0.55%). In addition, the previously reported advantages, such as excellent signal stability, wide dynamic range (up to 5% H2S) and convenient tuning of the sensitivity and linearity by varying the ratio between the gas and reagent flow rates were perfectly retained. The improved detector is utilized to construct a compact portable version of the H2S analyzer (∼6 kg), which provides a stand-alone operation for real-time monitoring of H2S in the gas stream for up to 4 h prior to the need for reagent refill or battery recharge. The applications of the described portable analyzer in monitoring H2S removal from H2S–N2 gas stream using an HFM contactor and absorption solvent, and in the determination of sulfide ions in liquid samples are presented. A comparison between the response of the present portable H2S analyzer and a commercial analyzer is also presented.

The use of high-performance liquid chromatography with diode array detector for the determination of sulfide ions in human urine samples using pyrylium salts

Hydrogen sulfide is a toxic gas involved in the regulation of some essential biological processes. A novel, precise, accurate and rapid method based on high-performance liquid chromatography with diode array detection for the determination of sulfide ions in human urine sample is proposed. The method involves the derivatization of sulfide with pyrylium salts – (2,4,6-triphenylpyrylium hydrogensulfate(VI) (L1) and 4-[p-(N,N-dimethylamino)phenyl]-2,6-diphenylpyrylium chlorate(VII) (LN1). The separation occurs on InfinityLab Poroshell 120 EC C18 column using acetonitrile and phosphate buffer as a mobile phase. The detectors utilized a wavelength of 371 or 580 nm. The calibration curves were linear in the range of 2–150 μmol L−1 and 1–50 μmol L−1 for L1 and LN1 derivatives, respectively. The samples were found to be stable from sample collection to final analysis. The method was successfully applied to samples from apparently healthy volunteers.

Dual fluorometric and colorimetric sensor based on quenching effect of copper (II) sulfate on the copper nanocluster for determination of sulfide ion in water samples

A new dual function sensor was developed for the sensitive and selective detection of sulfide ion in aqueous media. The proposed indirect measurement was based on the copper ion (Cu2+) mediated the fluorescence intensity of tannic acid-capped copper nanoclusters (TA-CuNCs) in the presence of sulfide ion. Under the optimal conditions, the fluorometric sensing of sulfide ion was carried out over the concentration ranges of 0.7–80.0 μM, without needing any etching time. Furthermore, fluorescence quenching is accompanied by color changing from sky blue to brown by increasing sulfide ion concentration that attributed to the formation of copper sulfide (CuS). The variations in the visible color of TA-CuNCs/Cu2+ in the presence of sulfide ion was recorded with a smart phone camera. The RGB color changes show a linear relationship with sulfide concentrations in the range of 6.0 – 130.0 μM. The fluorometric and colorimetric detection limit values were calculated as 0.1 μM and 2.0 μM, respectively. The estimated detection limits in both methods are lower than the permitted value reported by World Health Organization (WHO). The prepared TA-CuNCs/Cu2+ probe was successfully applied to the sensitive fluorometric and colorimetric determination of sulfide ion in different types of natural waters. The proposed probe is highly sensitive, selective and particularly useful for the fast and cost effective diagnosis of sulfide ion in environmental samples.

Silver nanoparticles capped with carbon dots as a fluorescent probe for the highly sensitive "off-on" sensing of sulfide ions in water.

The present study illustrates the synthesis of silver nanoparticles capped with carbon dots (AgNPs-CDs) and their application towards the sensitive and selective sensing of sulfide ions by colorimetry and spectrofluorimetry methods. The CDs were prepared from l-asparagine by pyrolysis at 234°C. The as-synthesized CDs were then utilized as reducing and capping agents for the synthesis of AgNPs-CDs by the wet chemical method. The size of the AgNPs-CDs was found to be ~ 5.2nm. They show a characteristic surface plasmon resonance band at 417nm and emission maximum at 441nm when excited at 348nm. Since the AgNPs were formed on the surface of CDs, the emission intensity of AgNPs-CDs was drastically decreased in contrast to that of CDs. The as-synthesized AgNPs-CDs were then successfully used for the sensitive and selective determination of sulfide ions. The addition of 0.1μM sulfide ions to AgNPs-CDs leads to a decrease in the absorbance intensity at 417nm aside turning from yellow to colorless. In the contrary, the emission was "turned on" after the addition of sulfide ions. The decrease in the absorbance and increase in the emission were attributed to the rapid formation of Ag2S. Finally, the practical application of the present method was demonstrated by determining dissolved H2S in tap water samples.

A novel “off-on” fluorescence nanosensor for sensitive determination of sulfide ions based on carbon quantum dots and gold nanoparticles: Central composite design optimization

In this research, a novel turn off-on fluorescent sensor for indirect determination of sulfide ions in aqueous media was designed based on carbon dots (CDs). This probe was established by using carbon dots in the present of gold nanoparticles (GNPs) and utilized as a fluorescence–enhancement probe. In this sensor, GNPs quenches the fluorescence of the CDs while addition of sulfide ions removes GNPs from the surface of CDs, resulting in regeneration of fluorescence intensity. The three factors of pH, time and temperature were selected for their effects on the sensing function to be optimized. The optimization of parameters was done by central composite design (CCD) through response surface methodology (RSM) application. The sensing results have proved the high selective and sensitive performance of the sensor. The linear range is 1.00–19.50 ppm and the detection limit is 0.57 ppm. The relative standard deviation (RSD) of the reported method is 2.53%.

Fluorometric determination of sulfide ions via its inhibitory effect on the oxidation of thiamine by Cu(II) ions.

A fluorometric assay is described for sulfide ions determination. It is based on the finding that the oxidation of the non-fluorescent substrate thiamine (TH) by Cu(II) in basic solution to form fluorescent thiochrome is inhibited by sulfide ions. This results in a decrease in fluorescence intensity which is proportional to the concentration of sulfide ions. Under the optimized conditions, the decrease in fluorescence, best measured at excitation/emission wavelengths of 370/440nm, decreases linearly in the 0.03 to 2.5μM sulfide ions concentration range. The detection limit is 20nM. The method shows excellent selectivity over many potentially interfering ions and has been successfullyapplied to the determination of sulfide ions in spiked tap water, lake water and thesynthetic wastewatersamples. The method is time-saving and environmentally friendly, and in our perception shows a great potential in water quality inspection and environmental monitoring. Graphical abstract A fluorescent assay for sulfide ions detection is proposed based on its inhibitory effect on the oxidation of thiamine by Cu(II) ions.

Charge Based Electrochemical Determination of Sulfide Ions in Water Samples Using Poly-L-Lysine Modified Electrode

The sulfide ions are easily found in real water and waste water samples, whilst it can lead to personal distress owing to their toxic effects on aquatic life. Thus, the determination of sulfide ion S2− in environmental samples is much important for human health. Hence, we developed an electrochemical sensor for charge based electrochemical determination of sulfide ions in water samples using poly-L-lysine modified electrode. The sulfide ions can oxidize on the PLL-film by taking an advantage of charge based concentration of sulfide ions. The PLL-modified electrode was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy. The PLL modified electrode exhibits excellent electrocatalytic activity towards the detection of sulfide ions. In addition, the LSV performance of PLL modified electrode offers a lower detection potential, higher sensitivity and fast response towards the detection of sulfide ions. The linear concentration for sulfide ions determination ranges from 11.8–6663 μM with a detection limit of 2.65 μM was observed. The proposed sensor offers high selectivity in presence of various anions and cations. Besides, the PLL-modified electrode exhibits good recovery results for the detection of sulfide ions in different water samples.

Determination of Sulfide Ion in Blood from Hydrogen Sulfide Poisoning Cases

To establish a gas chromatography-mass spectrometry （GC-MS） method for the determination of sulfide ion in blood and apply it to the practical cases. The 1, 3, 5-tribromobenzene was selected as an internal standard, and 0.2 mL blood sample was collected and analyzed using GC-MS after α-Bromo-2, 3, 4, 5, 6-pentafluorobenzyl bromide derivatization. The mass concentration of sulfide ion in blood had good linearity in the range of 0.2-40 μg/mL with a limit of detection （LOD） of 0.05 μg/mL. The mass concentration of sulfide ion was less than 0.05 μg/mL in blank blood from different sources such as healthy subjects and dead cases. In 3 sulfide poisoning cases, sulfide ion was detected in the blood samples of 6 victims, and the mass concentration range was 1.02-3.13 μg/mL. This study establishes a method for investigation of sulfide ion in blood which has been applied successfully to the cases of fatal sulfide poisonings.

Selective Determination of Chloride Ion and Sulfide Ion Using Flow Coulometry at Ag Electrode

[Introduction] Chloride ion and sulfide ion cause not only the pollution of air and water, but also the corrosion of metal construction. Therefore, it is necessary to establish the analytical method to determine chloride ion and sulfide ion quickly and precisely. If we can use the coulometry for the determination of these anions, it allows for the absolute determination method without the standard solution. Heretofore, we proposed the simplified flow cell, where a silver electrode, a reference electrode and a counter electrode are inserted in one tube of Teflon. The coulometric determination of chloride ion was accomplished successfully [1], but selective determination of the chloride ion and sulfide ion by connecting two cells was unsuccessful because of the pollution of chloride ion in the second step [2]. In this research, by using the tube made of cation exchange membrane, in which only a silver wire is inserted as a working electrode in tube, the electrolysis cell for chloride ion and that for sulfide ion were connected without interference of each other. The selective determination of two kinds of anion was performed by injection of the mixed sample and successive electrolysis in each cell. [Experimental] In the electrolytic cell, a silver wire was inserted into the tube made of cation exchange membrane, using 1 M (= mol dm-3) NaClO4 as a supporting electrolyte in the inside and outside solutions. In the measurement of cyclic voltammetry, the tube was filled with aqueous solution containing 10-4 ~ 10-3 M NaCl or Na2S. In the flow coulometry, while passing the supporting electrolyte solution in 0.01 ml/min, 20 μL of the aqueous solution containing NaCl or Na2S was injected from upstream. For the selective determination of mixed samples, the tubes of two cells were connected to attain one consistent flow. [Results and Discussion] In the determination of chloride ion, after the deposition of chloride ion as AgCl by applying 0.25 V vs. Ag/AgCl, chloride ion was determined from the electrical quantity of dissolution of AgCl at 0.05 V. The efficiency of electrolysis was 98 % in the concentration range of 10-4 ~ 10-3 M. In the determination of sulfide ion, the deposition of Ag2S is utilized, which occurred at more negative potentials than the deposition of AgCl and dissolution of Ag. The linear relationship between the electric quantity of Ag2S deposition and the concentration of sulfide ion was obtained, but the efficiency of electrolysis was about 35 % in the concentration range of sulfide ion was 10-4 ~ 10-3 M. We tried the successive determination of 5×10-4 M chloride ion and sulfide ion in the mixed solution. Chloride ion was determined from coulometry and sulfide ion was determined from the calibration curve, which indicated the possibility of the selective and successive determination of chloride ion and sulfide ion.[1] H. Fukutake, N. Okumura, Y. Tatsuno, Y. Yoshida, K. Maeda, Bunseki Kagaku, 61 (2012) 1055.[2] M. Sawada, H. Fukutake, Y. Yoshida, K. Maeda, Rev. Polarogr., 59 (2013) 195.

Graphene quantum dots combined with copper(II) ions as a fluorescent probe for turn-on detection of sulfide ions

A fluorescent probe for the sensitive and selective determination of sulfide ions is presented. It is based on the use of graphene quantum dots (GQDs) which emit strong and stable blue fluorescence even at high ionic strength. Copper(II) ions cause aggregation of the GQDs and thereby quench fluorescence. The GQDs-Cu(II) aggregates can be dissociated by adding sulfide ions, and this results in fluorescence turn on. The change of fluorescence intensity is proportional to the concentration of sulfide ions. Under optimal conditions, the increase in fluorescence intensity on addition of sulfide ions is linearly related (r 2 = 0.9943) to the concentration of sulfide ions in the range from 0.20 to 20 μM, and the limit of detection is 0.10 μM (at 3 σ/s). The fluorescent probe is highly selective for sulfide ions over some potentially interfering ions. The method was successfully applied to the determination of sulfide ions in real water samples and gave recoveries between 103.0 and 113.0 %.

Thin-layer chromatographic image analysis for the determination of sulfide ions using pyrylium cations

A highly specific and sensitive chromatographic method for the determination of sulfide ions was developed. The procedure is based on the sensitive and specific reaction of sulfide ions with 4-[p-(N,N-dimethylamino)phenyl]-2,6-diphenylpyrylium cations. The product of the reaction is a thiopyrylium derivative which can be quantitatively determined. Separations were performed on cellulose thin-layer chromatography (TLC) plates with a mixture of phosphoric buffer (pH 3.0), propan-2-ol, and acetonitrile (4:4:0.5, v/v) as the mobile phase. The thiopyrylium derivative was visible in the form of blue spots against a colorless background, which were converted into a chromatogram using TLSee software. Linearity was obtained in the range of 40–500 pmol per spot. The limits of detection and quantification were 10 pmol per spot and 33 pmol per spot, respectively. The proposed method was successfully used for the detection and determination of sulfide ions in water samples from the Busko Zdroj health resort.

Amperometric determination of sulfide ion by glassy carbon electrode modified with multiwall carbon nanotubes and copper (II) phenanthroline complex

Abstract Electrocatalytic oxidation of sulfide ion on a glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNTs) and a copper (II) complex was investigated. The Cu(II) complex was used due to the reversibility of the Cu(II)/Cu(III) redox couple. The MWCNTs are evaluated as a transducer, stabilizer and immobilization matrix for the construction of amperometric sensor based on Cu(II) complex adsorbed on MWCNTs immobilized on the surface of GCE. The modified GCE was applied to the selective amperometric detection of sulfide at a potential of 0.47 V (vs. Ag/AgCl) at pH 8.0. The calibration graph was linear in the concentration range of 5 µM–400 µM; while the limit of detection was 1.2 µM, the sensitivity was 34 nA µM−1. The interference effects of SO3 2−, SO4 2−, S2O3 2−, S4O6 2−, Cysteine, and Cystein were negligible at the concentration ratios more than 40 times. The modified electrode is more stable with time and more easily restorable than unmodified electrode surface. Also, modified electrode permits detection of sulfide ion by its oxidation at lower anodic potentials.

Selective spectrofluorimetric determination of sulfide ion using manganese doped ZnS quantum dots as luminescent probe

This work reports a spectrofluorimetric method for selective and sensitive determination of sulfide ion in aqueous solution. The ultra-small zinc sulfide quantum dots (QDs) doped with manganese (ZnS:Mn) were synthesized by using a simple and fast procedure based on the co-precipitation of nanoparticles in aqueous solution in the presence of 2-mercaptoethanol, as capping agent. The nanoparticles have exhibited two strong fluorescent emissions at about 424 and 594nm. Luminescent surface-capped ZnS:Mn QDs, with particle size below 5nm, have been applied for determination of sulfide anions in water samples. Under the optimum conditions, the fluorescence intensity of ZnS:Mn QDs is linearly proportional to the sulfide ion concentration in the range 1.2×10−6 to 2.6×10−5molL−1 with a detection limit as 3.3×10−7molL−1. The relative standard deviation for five replicate measurements (for 8.0×10−6molL−1 of S2−) was obtained to be 2.6%. It was founded that the interference of the other anions was negligible on the quantitive determination of sulfide ion.

Bismuth Film Electrodes for Indirect Determination of Sulfide Ion in Water Samples at Trace Level by Anodic Stripping Voltammetry

Bismuth Film Electrodes for Indirect Determination of Sulfide Ion in Water Samples at Trace Level by Anodic Stripping Voltammetry

Indirect determination of sulfide ions in water samples at trace level by anodic stripping voltammetry using mercury film electrode

A simple and sensitive indirect determination method for sulfide in water samples by anodic stripping voltammetry (ASV) using mercury-film electrode (MFE) has been developed, which is based on the determination of residual cadmium ion after reaction of Cd2+ with S2−. The linear range is adjustable depending on Cd2+ concentration, for example, the determination of S2− can be achieved in the range of 1.5–7.0 × 10−6 mol L−1 by selecting 3.0 × 10−6 mol L−1 Cd2+. The detection limit is 1.3 × 10−8 mol L−1 under optimum conditions, and the relative standard deviation (RSD, n = 10) for 2.0 × 10−6 mol L−1 S2− is 0.7%. Compared with other methods, this method has the following prominent advantages: with low detection limit, easy to operate and less interference. The proposed method has been successfully applied to the determination of S2− in synthetic wastewater, lake water, beverage, spring water and real wastewater samples.

Detection of Sulfide Release from the Oxygen-sensing [4Fe-4S] Cluster of FNR

The Escherichia coli FNR protein regulates the transcription of >100 genes in response to environmental O2, thereby coordinating the response to anoxia. Under O2-limiting conditions, FNR binds a [4Fe-4S]2+ cluster through four cysteine residues (Cys20, Cys23, Cys29, Cys122). The acquisition of the [4Fe-4S]2+ cluster converts FNR into the transcriptionally active dimeric form. Upon exposure to O2, the cluster converts to a [2Fe-2S]2+ form, generating FNR monomers that no longer bind DNA with high affinity. The mechanism of the cluster conversion reaction and the nature of the released iron and sulfur are of considerable current interest. Here, we report the application of a novel in vitro method, involving 5,5'-dithiobis-(2-nitrobenzoic acid), for determining the oxidation state of the sulfur atoms released during FNR cluster conversion following the addition of O2. Conversion of [4Fe-4S]2+ to [2Fe-2S]2+ clusters by O2 for both native and reconstituted FNR results in the release of approximately 2 sulfide ions per [4Fe-4S]2+ cluster. This demonstrates that the reaction between O2 and the [4Fe-4S]2+ cluster does not require sulfide oxidation and hence must entail iron oxidation.

Methylene blue potentiometric sensor for selective determination of sulfide ions

A new poly(vinyl chloride) (PVC) membrane sensor for methylene blue cation (MB +) is prepared, characterized and used for determination of sulfide ions. The sensor shows a cationic response slope of 56.2±0.3 mV per concentration decade and a linear response range of 6×10 −7 to 10 −4 mol l −1 MB + with a lower detection limit of 3.8×10 −7 mol l −1 MB + in Tris buffer of pH 8.7. The sensor is used for determination of sulfide ions after conversion into MB using Caro’s reaction. Optimized reaction conditions result in a wide dynamic, linear response range (0.12–15 μg ml −1 sulfide–sulfur), short reaction time (1–2 min), low detection limit (0.01 μg ml −1 sulfide–sulfur), high accuracy (>98% recovery) and remarkable selectivity. The method displays significant advantages over many other techniques used for quantification of sulfide ions. Determination of sulfide ions in real samples of complex matrices, e.g. wastewaters gives results that compare fairly well with those obtained with the standard methods. The sensor is also used to monitor titration of some complex anions such as reineckate, hexanitrocobaltate(III), tetraphenylborate and tetraiodomercurate with MB as a titrant.

Determination of Trace Sulfate Ions by Stripping Voltammetry at a Renewed Silver Electrode

The determination of trace sulfate ions by the known methods is considered. The most sensitive methods are based on the reduction of sulfate ions to hydrogen sulfide followed by the detection of H2S in absorbing alkaline solutions. The properties of reducing mixtures of different compositions were tested experimentally. Working conditions were selected for the reduction of sulfate ions and the determination of sulfide ions by stripping voltammetry at a silver electrode renewed on line by cutting off a thin layer. The detection limit for sulfate ions was 10–5% in a 0.1-g sample.

Fluorimetric optode membrane for sulfide detection

Sulfide-selective optode membranes have been fabricated by immobilizing tetraoctylammonium fluorescein mercuric acetate (TOAFMA), tetraoctylammonium hydroxide and tri-n-butyl phosphate into ethyl cellulose. These membranes were coated on overhead transparency films as solid supports and employed as sensing devices for fluorimetric determination of sulfide ions in pH buffered solutions. The sensing scheme is based on a ground state chemical reaction of TOAFMA and hydrosulfide leading to the formation of a non-fluorescent fluorescein mercuric sulfide, which can be related to the concentration of the sulfide ions present in solution. The response behaviour of the membrane is slightly pH dependent at pH values higher than 10.0. At pH 12.5, the useful detection range is 0.07 to 4.4 µmol dm–3 of sulfide ions since this range has better response to Na2S. The detection limit is calculated to be 0.07 µmol dm–3. The concentrations of sulfide ions in spiked water samples determined by the sulfide-selective optode membranes at pH 12.5 were found to reasonably agree with the added concentrations. The optode membrane has a fast response time of less than 1 min. The fluorescence signal of the optode membrane can easily be recovered by rinsing with a solution of 0.42 mmol dm–3 of sodium hypochlorite and 0.10 mmol dm–3 of sodium acetate. Anions including bromide, nitrate, perchlorate and dichromate interfere seriously with the detection but other anions such as sulfite, oxalate, thiosulfate, iodide, sulfate, nitrite, acetate, fluoride, chloride and carbonate either do not interfere or interfere slightly.