Detection Of Sulfur Dioxide Research Articles

A mitochondria-targeted ratiometric probe for the fluorescent and colorimetric detection of SO2 derivatives in live cells

An abnormal endogenous SO2 level can induce toxicological effects leading to cancer, cardiovascular diseases, and neurological disorders, as they involve in various physiology and pathological processes in mitochondria cell apparatus. In this study, we report a ratiometric fluorescent probe (NAB-Id) based on the cyanine dye for the detection of sulfur dioxide (SO2) derivatives in aqueous media and live cells. Upon the addition of SO2 derivatives (SO32−/HSO3−) to the solution of NAB-Id, led to the nucleophilic addition to the polymethine, resulting in dramatic colorimetric and fluorescence dual responses. NAB-Id responses to HSO3− with low detection limit (58.6nM), outstanding specificity (without the interfering of H2S), fast response (t1/2 = 30s) and working well at physiological pH. Fluorescence co-localization studies demonstrated that NAB-Id was a mitochondria-targeted fluorescent probe for the real-time sensing and bioimaging of SO2 derivatives in living cells.

A Comparative Study of Zinc Oxide Based Chemical Gas Sensors for Sulfur Dioxide Detection

A Comparative Study of Zinc Oxide Based Chemical Gas Sensors for Sulfur Dioxide Detection

Developing fast laboratory screening platform for sulfate dioxide in food by surface-enhanced Raman spectroscopy

The direct detection of sulphur dioxide has been realized in various food matrixes with high sensitivity and high selectivity, on the basis of the integration of the high energy resolution of the finger-print spectrum of surface-enhanced Raman spectroscopy and the universal but easy-on-going pretreatment procedure. The characteristic peak of sulphur dioxide at ~630 cm−1 was applied as the qualitative and quantitative standard, which displayed a lowest detectable concentration at the 1 mg kg−1 level for the spiked food samples. The key point of the high sensitivity and selectivity is the effective pretreatment born out of the standard distillation one, which has been improved in the three parts. (1) Using CaCO3 and Zeolite instead of N2 gas as the bubbling reagent. (2) Using oxalic acid as the acidic distillation solution to eliminate the hazards from acid volatilization, such as hydrochloric acid. (3) Using diluted sodium hydroxide solution as the absorption reagent instead of lead acetate solution to avoid the secondary pollution. With the three distinguished advantages of environment friendly, high sensitivity and free of matrix interference, the proposed method has great potential to replace the traditional ones for the fast screening of the illegal or abused sulphur dioxide in food.

Analysis of free and total sulfur dioxide in wine by using a gas-diffusion analytical system with pH detection.

The use of sulfur dioxide as preservative in winemaking industry has a direct impact on wine quality. The standard methods to analyze this parameter require several processes and are time consuming. In this paper a simple and rapid analytical method for free and total sulfur dioxide detection is proposed. This method is based on the separation of the analyte from the sample with a permeable gas diffusion membrane and its indirect detection with a pH sensor. The system has been validated and optimized for free sulfur dioxide detection in the range of 1-60mgL-1 and for total sulfur dioxide in the range of 30-300mgL-1 with a limit of detection of 0.5mgL-1. Validation of the system has been carried out using a total of 70 samples of white and red wines and two standard methods, the Ripper and the Paul method. The obtained values have demonstrated a good agreement for both methods.

Rapid integrated microfluidic paper-based system for sulfur dioxide detection

An integrated platform consisting of a microfluidic paper-based/PMMA (Polymethyl-Methacrylate) chip and a small battery-operated detection system is proposed for the concentration detection of sulfur dioxide (SO2). In the proposed method, a small strip of filter paper is coated with acid-base indicator and then inserted into a PMMA microchip. The SO2 sample is then injected into the reservoir of the chip; prompting a reaction with the acid-base indicator. The chip is transferred to the detection system, where the reaction-induced color change is captured by a CMOS (Complementary Metal-Oxide Semiconductor) camera. Finally, the CMOS image is transferred to a cell phone via a USB (Universal Serial Bus) connector and the SO2 concentration is derived using self-written RGB color analysis software. The experimental results obtained for 10 control samples show that the correlation coefficient for the variation of the R(ed) signal intensity with the SO2 concentration is equal to R2=0.9971 in the low-concentration range (20∼600ppm) and R2=0.9920 in the high-concentration range (600∼5000ppm). The real-world applicability of the proposed platform is demonstrated by measuring the SO2 concentrations of fifteen commercial food samples. The concentration measurements deviate by no more than 4.29% from those obtained using a standard macroscale technique. Overall, the results presented in this study show that the proposed integrated microfluidic paper-based system provides a cheap, compact and reliable method for SO2 concentration measurement purposes.

Application of Near-Infrared Hyperspectral Imaging to Detect Sulfur Dioxide Residual in the Fritillaria thunbergii Bulbus Treated by Sulfur Fumigation

Sulfur-fumigated Chinese medicine is a common issue in the process of Chinese medicines. Detection of sulfur dioxide (SO2) residual content in Fritillaria thunbergii Bulbus is important to evaluate the degree of sulfur fumigation and its harms. It helps to control the use of sulfur fumigation in Fritillaria thunbergii Bulbus. Near-infrared hyperspectral imaging (NIR-HSI) was explored as a rapid, non-destructive, and accurate technique to detect SO2 residual contents in Fritillaria thunbergii Bulbus. An HSI system covering the spectral range of 874–1734 nm was used. Partial least squares regression (PLSR) was applied to build calibration models for SO2 residual content detection. Successive projections algorithm (SPA), weighted regression coefficients (Bw), random frog (RF), and competitive adaptive reweighted sampling (CARS) were used to select optimal wavelengths. PLSR models using the full spectrum and the selected optimal wavelengths obtained good performance. The Bw-PLSR model was applied on a hyperspectral image to form a prediction map, and the results were satisfactory. The overall results in this study indicated that HSI could be used as a promising technique for on-line visualization and monitoring of SO2 residual content in Fritillaria thunbergii Bulbus. Detection and visualization of Chinese medicine quality by HSI provided a new rapid and visual method for Chinese medicine monitoring, showing great potential for real-world application.

2f-wavelength modulation Fabry-Perot photothermal interferometry.

Trace gas detection was performed by the principle of photothermal interferometry using a Fabry-Perot interferometer combined with wavelength modulation and second harmonic detection. The sensor employed a compact, low-volume gas cell in an overall robust set-up without the use of any moveable part. A quantum cascade laser was used as powerful mid-infrared excitation source to induce refractive index changes in the sample, whereas a near-infrared laser diode served as probe source to monitor the photo-induced variations. The functional principle of the selective sensor was investigated by detection of sulfur dioxide. For the targeted absorption band centered at 1379.78 cm-1 a 1 σ minimum detection limit of about 1 parts per million by volume was achieved. The work demonstrates high potential for further sensor miniaturization down to a sample volume of only a few mm3. Limitations and possible improvements of the sensor regarding sensitivity are discussed.

Optical sulfur dioxide sensor based on broadband absorption spectroscopy in the wavelength range of 198–222 nm

A highly sensitive sulfur dioxide detection system based on broadband absorption spectroscopy was developed using the 198–222nm wavelength range. The compact and simple measurement system was constructed utilizing fiber optoelectronic sensing device. A modified approach based on differential optical absorption spectroscopy was used for the computation of sulfur dioxide concentrations. The results of sulfur dioxide concentration were calibrated and displayed using a LabVIEW-based software. A system detection limit of 17ppb per meter has been reached, and a ten-fold improvement in sensitive and uncertainty has been achieved for measuring sulfur dioxide concentrations. The system is suitable for monitoring sulfur dioxide concentration in air as well as for the fault diagnosis of gas insulated switchgears.

Manipulating the Surface Chemistry of Quantum Dots for Sensitive Ratiometric Fluorescence Detection of Sulfur Dioxide.

Herein, we report a novel approach to the rapid visual detection of gaseous sulfur dioxide (SO2) by manipulating the surface chemistry of 3-aminopropyltriethoxysilane (APTS)-modified quantum dots (QDs) using fluorescent coumarin-3-carboxylic acid (CCA) for specific reaction with SO2. The CCA molecules are attached to the surface amino groups of the QDs through electrostatic attraction, thus the fluorescence of CCA is greatly suppressed because of the formation of an ion-pair complex between the ATPS-modified QDs and CCA. Such an interaction is vulnerable to SO2 because SO2 can readily react with surface amino groups to form strong charge-transfer complexes and subsequently release the strongly fluorescent CCA molecules. The mechanism has been carefully verified through a series of control experiments. Upon exposure to different amounts of SO2, the fluorescent color of the nanoparticle-based sensor displays continuously changes from red to blue. Most importantly, the approach owns high selectivity for SO2 and a tolerance of interference, which enables the sensor to detect SO2 in a practical application. Using this fluorescence-based sensing method, we have achieved a visual detection limit of 6 ppb for gaseous SO2.

A ratiometric fluorescent probe for rapid, sensitive and selective detection of sulfur dioxide with large Stokes shifts by single wavelength excitation.

4-(Benzothiazol-2-yl)-3-hydroxybenzaldehyde, probe 1, has been developed as a ratiometric fluorescent probe for the sensitive and selective detection of sulfur dioxide with a fast response time (within seconds). This probe itself exhibited a yellow emission (λmaxem = 563 nm) with a 186 nm Stokes shift. Upon treatment with sulfite anions, this probe instantaneously displayed a blue emission (λmaxem = 467 nm) with a 133 nm Stokes shift. The large Stokes shifts and absorption spectral overlap of probe 1 both in the absence and in the presence of SO3(2-)/HSO3(-) allow the fluorescence detection under single wavelength excitation. Importantly, this ratiometric probe was successfully demonstrated for the imaging of intracellular sulfite anions in living cells.

Headspace thin-film microextraction coupled with surface-enhanced Raman scattering as a facile method for reproducible and specific detection of sulfur dioxide in wine.

By coupling thin-film microextraction (TFME) with surface-enhanced Raman scattering (SERS), a facile method was developed for the determination of sulfur dioxide (SO2), the most effective food additive in winemaking technology. The TFME substrate was made by free settling of sea urchin-like ZnO nanomaterials on a glass sheet. The headspace sampling (HS) procedure for SO2 was performed in a simple homemade device, and then the SO2 was determined using SERS after uniformly dropping or spraying a SERS-active substrate (gold nanoparticles, AuNPs) onto the surface of the TFME substrate. A reproducible and strong SERS response of the SO2 absorbed onto the ZnO substrate was obtained. After condition optimization, the SERS signal intensity at a shift of 600 cm(-1) and the SO2 concentration showed a good linearity in the range of 1-200 μg/mL, and the linear correlation coefficient was 0.992. The detection limit for SO2 was found to be 0.1 μg/mL. The HS-TFME-SERS method was applied for the determination of SO2 in wine, and the results obtained agreed very well with those obtained using the traditional distillation and titration method. Analysis of variance and Student t test show that there is no significant difference between the two methods, indicating that the newly developed method is fast, convenient, sensitive and has selective characteristics in the determination of SO2 in wine.

A Fabry–Perot interferometer-based camera for two-dimensional mapping of SO<sub>2</sub> distributions

Abstract. We examine a new imaging method for the remote sensing of volcanic gases, which relies on the regularly spaced narrow-band absorption structures in the UV–VIS of many molecules. A Fabry–Perot interferometer (FPI) is used to compare the scattered sunlight radiance at wavelengths corresponding to absorption bands with the radiance at wavelengths in between the bands, thereby identifying and quantifying the gas. In this first theoretical study, we present sample calculations for the detection of sulfur dioxide (SO2). Optimum values for the FPI setup parameters are proposed. Furthermore, the performance of the FPI method is compared to SO2 cameras. We show that camera systems using an FPI are far less influenced by changes in atmospheric radiative transfer (e.g., due to aerosol) and have a great potential as a future technique for examining emissions of SO2 (or other gases) from volcanic sources and other point sources.

Simultaneous detection of SO2, SO3 and H2O using QCL spectrometer for combustion applications

We demonstrate a high-sensitivity laser-based spectrometer for simultaneous detection of sulphur dioxide (SO2) sulphur trioxide (SO3) and water for coal-fired combustion applications. The spectrometer is based on a quantum-cascade laser (QCL) operating at 7.16 μm, capable of measuring all three components simultaneously in a single frequency sweep. An optical multipass cell having a total path length of 9.1 m is used at increased temperature and at low pressure to ensure reliable measurement of highly reactive SO3 and adequate separation of overlapping spectral features, respectively. Detection limits for SO2 and SO3 are 0.134 and 0.0073 ppm, respectively, when employing a 20-s sampling time.

Quartz-enhanced photoacoustic spectroscopy-based sensor system for sulfur dioxide detection using a CW DFB-QCL

Sulfur dioxide (SO2) trace gas detection based on quartz-enhanced photoacoustic spectroscopy (QEPAS) using a continuous wave, distributed feedback quantum cascade laser operating at 7.24 μm was performed. Influence of water vapor addition on monitored QEPAS SO2 signal was also investigated. A normalized noise equivalent absorption coefficient of NNEA (1σ) = 1.21 × 10−8 cm−1 W Hz−1/2 was obtained for the ν3 SO2 line centered at 1,380.93 cm−1 when the gas sample was moisturized with 2.3 % H2O. This corresponds to a minimum detection limit (1σ) of 63 parts per billion by volume for a 1 s lock-in time constant.

Integrated microfluidic array chip and LED photometer system for sulfur dioxide and methanol concentration detection

An integrated platform comprising a PMMA (Polymethyl-Methacrylate) microfluidic array chip and a LED photometer system is proposed for the concentration detection of sulfur dioxide (SO2) and methanol (CH4O). In the proposed device, the sample and reagent are injected into six open chambers on the microfluidic chip and are mixed via a vortex stirring effect. Following the mixing process, a colorimetric reaction is induced between the sample and the reagent by means of a microhotplate positioned beneath the microfluidic chip array. The microfluidic chip is then transferred to a LED photometer system for detection purposes. The experimental results show that correlation coefficients of R2=0.9915 and R2=0.9941 are obtained when plotting the photometer output voltage against the SO2 and CH4O concentrations of control samples with known concentrations ranging from 50 to 500ppm. The real-world applicability of the proposed experimental platform is demonstrated by measuring the SO2 concentration in two commercial Chinese herbs and the CH4O concentration in two commercial wines. It is shown that the concentration measurements obtained using the proposed system deviate by no more than 9% from those obtained using standard macroscale methods. Overall, the results presented in this study show that the proposed integrated microfluidic platform provides a compact and reliable tool for SO2 and CH4O concentration measurement purposes.

An ionic liquid-mediated electrochemiluminescent sensor for the detection of sulfur dioxide at the ppb level

A novel portable SO2 gas sensor based on ionic liquid (IL) mediated electrochemiluminescence (ECL) for detecting SO2 at the ppb levels has been developed. The sensing system for SO2 detection is based on the strong quenching effect of SO2 on the ECL of the tris(2,2'-bipyridine)ruthenium(ii) (Ru(bpy)3(2+))/O2 coreactant system in the IL film. Over the potential window between -1.0 and +1.3 V, O2 can act as an effective coreactant for Ru(bpy)3(2+) ECL in ILs, giving a bright ECL emission. The ECL of the Ru(bpy)3(2+)/O2 system can be strongly inhibited by SO2 through the direct quenching of the excited state of the luminophore, i.e. Ru(bpy)3(2+)*, by SO2 molecules. The inhibited ECL intensity is proportional to the concentration of SO2 in the range from 40 to 2000 ppb with a detection limit of 20 ppb. The proposed SO2 ECL sensor can be operated at room temperature and shows high selectivity, good reproducibility and long-term stability in a dry atmosphere.

Edge-tailored graphene oxide nanosheet-based field effect transistors for fast and reversible electronic detection of sulfur dioxide

Graphene oxide was tailored into GO nanosheets with periodic acid treatment. Interestingly, the latter have a superior sensing performance for the fast and reversible detection of SO(2) compared with the former at room temperature. Its sensing mechanism was proposed from the structural changes of the GO nanosheets during the sensing and recovering processes.

Electronic sensor for sulfide dioxide based on AlN nanotubes: a computational study

Single-walled aluminum nitride nanotubes (AlNNTs) are introduced as an electronic sensor for detection of sulfur dioxide (SO₂) molecules based on density functional theory calculations. The proposed sensor benefits from several advantages including high sensitivity: HOMO-LUMO energy gap of the AlNNT is appreciably sensitive toward the presence of SO₂ so that it decreases from 4.11 eV in the pristine tube to 1.01 eV in the SO₂-adsorbed form, pristine application: this nanotube can detect the SO₂ molecule in its pristine type without manipulating its structure through doping, chemical functionalization, making defect, etc., short recovery time: the adsorption energy of SO₂ molecule is not so large to hinder the recovery of AlNNTs and therefore the sensor will possess short recovery times, and good selectivity: the tube can selectively detect the SO₂ molecule in the presence of several molecules such as H₂O, CO, NH₃, HCOH, CO₂, N₂, and H₂.

Improved detection of sulphur dioxide in volcanic plumes using satellite‐based hyperspectral infrared measurements: Application to the Eyjafjallajökull 2010 eruption

The explosive phase of the eruption of the Eyjafjallajökull volcano in Iceland beginning on 14 April 2010 caused extensive disruption to aviation in Europe with serious social and economic consequences. Despite its impact, the explosive phase was modest in size and the amount of sulphur dioxide (SO2) released was low. The potential of hyperspectral thermal infrared measurements to discriminate emissions from similar events by measuring SO2 is examined using the Infrared Atmospheric Sounding Interferometer (IASI) on board MetOp‐A. The transported plume in the initial stages of the explosive phase contained low amounts of SO2 at low altitude which placed it at the detection limit of space‐based sensors used to monitor the volcanic threat to aviation using current methods. A recently developed technique for the fast retrieval of SO2 from IASI is applied in the context of the Eyjafjallajökull eruption to show that IASI is easily capable of sensing the SO2 in the plume at this stage where existing methods fail. The fast SO2 retrieval is calibrated against a fully quantitative optimal estimation retrieval of SO2 total column amount and plume altitude to derive the detection limit for the plume on 15 April 2010. An estimate of the general detection limit for the instrument is placed conservatively at 0.3 Dobson Units (DU) which is an order of magnitude lower than previously thought.

Compact, DC-electrical biased sulfur dioxide sensing elements for use at high temperatures

Fabrication and operation of sensing elements for the detection of sulfur dioxide (SO2) at high temperature (800–900°C) are reported. The sensing elements consisted of three (two oxide and one Pt) electrodes on yttria-stabilized zirconia substrates. To operate the elements, a DC current (on the order of 0.1mA) is driven between two of the electrodes and the voltage between one of these electrodes and the third electrode is used as the sensing signal. These sensing elements respond very strongly to SO2, for example when one of these sensing elements was operated at 900°C, 2ppmV of SO2 in a background of 7vol% O2, balance N2 was found to produce a >10% change in the sensing signal, which could be easily detected. Sensing elements fabricated to be nominally identical were shown to yield qualitatively identical sensing behavior, and temperature, oxygen content, and flow were all found to strongly impact sensing performance. The effect of interferents, such as NOx and CO, was evaluated and found to be relatively small in comparison to the SO2 response. The sensing response, over a 1 month period, was very stable, with the ratio of the average change in sensing signal over one day to the average sensing signal magnitude being about 0.1%.