Determination Of Thiocyanate Research Articles

Mxene Quantum Dot Nanosurface Molecularly Imprinted Polymer Resonance Rayleigh Scattering Probe for Highly Sensitive and Selective Determination of Thiocyanate.

In this article, a nanosurface molecularly imprinted polymer (MQD@MIP) resonance Rayleigh scattering (RRS) spectral probe for SCN- was prepared by sol-gel method, using Mxene quantum dot as a matrix, thiocyanate (SCN-) as a template ion, (3-aminopropyl) triethoxysilane (APTES) as a functional monomer, tetraethoxysilane (TEOS) as the cross-linker, and ammonia as the initiator. The probe produced an RRS peak at 370 nm and exhibits a strong RRS energy transfer (RRS-ET) effect when the MQD@MIP probe identifies SCN-. As the concentration of SCN- increased, the RRS-ET was enhanced, and the signal value of the system decreased linearly at 370 nm, with a determination range of 0.87-5.22 μg/L, and a detection limit of 0.37 μg/L SCN-. This detection method has the characteristics of simplicity, sensitivity, and specific recognition. The RRS method was used to determine SCN- in the sample, with relative standard deviation of 1.95-10.98% and recovery of 89.0-102.8%.

Aqueous Two-Phase Flotation Combined with Gold Nanoparticle Colorimetry for Determination of Thiocyanate in Raw Milk

Thiocyanates are effective in inhibiting the growth of microorganisms in raw milk to extend shelf life, but excessive addition can cause human health problems. Currently, ion chromatography and spectrophotometry are the main methods used in industry to determine SCN, but the pre-treatment process is cumbersome and time-consuming and has low sensitivity. Aqueous two-phase flotation (ATPF) technology has the advantages of simplicity, rapidity and economy. In this study, an acetonitrile/ammonium sulfate ATPF–gold nanoparticle (AuNP) colorimetric method was developed for the determination of SCN− in raw milk, and ATPF was used to separate and concentrate SCN− in raw milk to improve the detection sensitivity under convenient and economical conditions. The separation conditions were optimized by single-factor experiments and RSM, while the detection conditions, effects of CTAB concentration, pH and reaction time, were investigated. The “aggregation–anti-aggregation” mechanism of the gold-nano colorimetric method for the determination of SCN− was investigated by UV-vis absorption spectroscopy (UV-vis) and transmission electron microscopy (TEM). Under the optimal separation and detection conditions, the SCN− concentration showed a linear relationship with A630/A520 values in the concentration range of 0–2.5 mg/L with R2 of 0.9933, limit of detection (LOD) of 0.0919 mg/L, limit of quantitation (LOQ) of 0.306 mg/L, intra-day precision of 5.3% and spiked recoveries of 80.91–101.25%. In addition, the ATPF-AuNP colorimetric method demonstrated high selectivity and stability.

Nanostructured cobalt(II) phthalocyanine modified screen‐printed electrodes for the determination of thiocyanate in human saliva

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Semiquantitative Determination of Thiocyanate in Saliva Through Colorimetric Assays: Design of CNN Architecture via Input-Aware NAS

Semiquantitative Determination of Thiocyanate in Saliva Through Colorimetric Assays: Design of CNN Architecture via Input-Aware NAS

Concurrent determination of cyanide and thiocyanate in human and swine antemortem and postmortem blood by high-performance liquid chromatography-tandem mass spectrometry.

Cyanide (in the form of cyanide anion (CN-) or hydrogen cyanide (HCN), inclusively represented as CN) can be a rapidly acting and deadly poison, but it is also a common chemical component of a variety of natural and anthropogenic substances. The main mechanism of acute CN toxicity is based on blocking terminal electron transfer by inhibiting cytochrome c oxidase, resulting in cellular hypoxia, cytotoxic anoxia, and potential death. Due to the well-established link between blood CN concentrations and the manifestation of symptoms, the determination of blood concentration of CN, along with the major metabolite, thiocyanate (SCN-), is critical. Because currently there is no method of analysis available for the simultaneous detection of CN and SCN- from blood, a sensitive method for the simultaneous analysis of CN and SCN- from human ante- and postmortem blood via liquid chromatography-tandem MS analysis was developed. For this method, sample preparation for CN involved active microdiffusion with subsequent chemical modification using naphthalene-2,3-dicarboxaldehyde (NDA) and taurine (i.e., the capture solution). Preparation for SCN- was accomplished via protein precipitation and monobromobimane (MBB) modification. The method produced good sensitivity for CN with antemortem limit of detection (LODs) of 219 nM and 605 nM for CN and SCN-, respectively, and postmortem LODs of 352 nM and 509 nM. The dynamic ranges of the method were 5-500µM and 10-500µM in ante- and postmortem blood, respectively. In addition, the method produced good accuracy (100 ± 15%) and precision (≤ 15.2% relative standard deviation). The method was able to detect elevated levels of CN and SCN- in both antemortem (N = 5) and postmortem (N = 4) blood samples from CN-exposed swine compared to nonexposed swine.

Amperometric determination of salivary thiocyanate using electrochemically fabricated poly (3, 4-ethylenedioxythiophene)/MXene hybrid film

Thiocyanate (SCN) is a hazardous byproduct of the detoxification of cyanide. Even in minute quantity, the SCN has a negative impact on health. Although there are several ways for SCN analysis, an efficient electrochemical procedure has hardly ever been attempted. Here, the author reports the development of a highly selective and sensitive electrochemical sensor for SCN utilizing Poly (3, 4-Ethylenedioxythiophene) incorporated MXene (PEDOT/MXene) modified screen-printed electrode (SPE). The Raman, X-ray photoelectron (XPS), and X-ray diffraction (XRD) analyses support the effective integration of PEDOT on the MXene surface. Further, scanning electron microscopy (SEM) is employed to demonstrate the formation of MXene and PEDOT/MXene hybrid film. In order to specifically detect SCN in phosphate buffer media (pH 7.4), the PEDOT/MXene hybrid film is grown on the SPE surface via the electrochemical deposition method. Under the optimized condition, the PEDOT/MXene/SPE-based sensor provides a linear response against SCN from 10 to 100 µM and 0.1 μM to 1000 μM with the lowest limit of detections (LOD) of 1.44 μM and 0.0325 μM by differential pulse voltammetry (DPV) and amperometry, respectively. For accurate detection of SCN, our newly created PEDOT/MXene hybrid film-coated SPE demonstrates excellent sensitivity, selectivity, and repeatability. Ultimately, this novel sensor can be used to detect SCN precisely in environmental and biological samples.

Evaluation of the Effects of Processing Technique on Chemical Components in Raphani Semen by HPLC and UPLC-Q-TOF-MS.

In this study, the effects of different processing techniques on the chemical components of Raphani Semen (RS) were evaluated. An established high-performance liquid chromatography (HPLC) method was adopted for the simultaneous determination of glucoraphanin, sinapine thiocyanate, raphanin, and erucic acid in the fried products of Raphani Semen to evaluate the chemical changes during frying processing as well as optimize the best frying technology of Raphani Semen. Then, the chemical components in the fried Raphani Semen were identified by ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). A total of 54 compounds in processed Raphani Semen were identified by UPLC-Q-TOF-MS. The results showed that the content of glucoraphanin and sinapine thiocyanate was the highest in the fried products at 130°C for 10 min, and the effect of “Enzyme Killing and Glycosides Preserving” was the best. Therefore, this condition was chosen as the best frying technology of Raphani Semen. This study provided a more scientific basis for evaluation of the quality of Raphani Semen fried products and optimization of the frying technology of Raphani Semen.

The determination of thiocyanate in the blood plasma and holding water of Amphiprion clarkii after exposure to cyanide.

The illegal practice of cyanide fishing continues throughout the Indo-Pacific. To combat this destructive fishing method, a reliable test to detect whether a fish has been captured using cyanide (CN) is needed. We report on the toxicokinetics of acute, pulsed CN exposure and chronic thiocyanate (SCN) exposure, the major metabolite of CN, in the clownfish species, Amphiprion clarkii. Fish were pulse exposed to 50 ppm CN for 20 or 45 s or chronically exposed to 100 ppm SCN for 12 days and blood plasma levels of SCN were measured. SCN blood plasma levels reached a maximum concentration (301–468 ppb) 0.13–0.17 days after exposure to CN and had a 0.1 to 1.2 day half-life. The half-life of blood plasma SCN after chronic exposure to SCN was found to be 0.13 days. Interestingly, we observed that when a fish, with no previous CN or SCN exposure, was placed in holding water spiked to 20 ppb SCN, there was a steady decrease in the SCN concentration in the holding water until it could no longer be detected at 24 hrs. Under chronic exposure conditions (100 ppm, 12 days), trace levels of SCN (∼40 ppb) were detected in the holding water during depuration but decreased to below detection within the first 24 hrs. Our holding water experiments demonstrate that low levels of SCN in the holding water of A. clarkii will not persist, but rather will quickly and steadily decrease to below detection limits refuting several publications. After CN exposure, A. clarkii exhibits a classic two compartment model where SCN is eliminated from the blood plasma and is likely distributed throughout the body. Similar studies of other species must be examined to continue to develop our understanding of CN metabolism in marine fish before a reliable cyanide detection test can be developed.

Aqueous Two-Phase System–Ion Chromatography for Determination of Thiocyanate in Raw Milk

Thiocyanate could effectively inhibit bacteria in milk and extend the shelf life of milk. However, excessive addition will lead to health risks. Therefore, the determination of thiocyanate in raw milk has received a lot of attention, but the determination could be interfered with by other components in raw milk and the pre-treatment of raw milk is complex. In this study, a new pretreatment method combined with ion chromatography (IC) for rapid and sensitive determination of thiocyanate is proposed. An acetonitrile/(NH4)2SO4 aqueous two-phase system (ATPS) was developed for the separation and enrichment of thiocyanate in raw milk. Response surface methodology was performed to optimize the extraction conditions and an efficient pretreatment were obtained using ATPS composed of 42% acetonitrile (w/w) and 16% (NH4)2SO4 (w/w), with the pH 4.7, and the recovery of thiocyanate reached 107.24 ± 0.5%, and the enrichment ratio was 10.74 ± 0.03. IC was used to establish a thiocyanate enrichment method. The linear range was from 0.05 to 15 mg/L and R2 = 0.998, the limit of detection (LOD) was 0.2 μg/L, the limit of quantification (LQD) was 0.6 μg/L. Hence, it is feasible to combine ATPS with IC for the enrichment and determination of thiocyanate in raw milk.

A colorimetric paper-based optode sensor for highly sensitive and selective determination of thiocyanate in urine sample using cobalt porphyrin derivative

In this work, a highly sensitive colorimetric paper-based optode for the determination of thiocyanate in urine samples was developed for the first time. The cocktail solution of the optode was composed of 5,10,15,20-tetrakis(4-octyloxyphenyl)porphyrin cobalt(II) complex (L), tridodecylmethylammonium chloride (TDMACl), 2-nitrophenyl octyl ether, and polyvinyl chloride as an ionophore, an ion exchanger, a plasticizer, and a polymer, respectively. The paper-based optode responded to thiocyanate by increasing the blue component in the RGB index and a visible change, with the naked-eye, of the optode color from pink to green was observed. From the central composite design, the optimized conditions that yielded the highest sensitivity were 4.70 mmol/kg TDMACl and 13.75 mmol/kg L. The developed optode sensor was highly selective and responded to thiocyanate over other anions, with a working range of 0.001–5 mM and with a coefficient of determination (R2) of 0.9915. The limits of detection using naked-eye and camera were determined to be 50.0 μM and 1.26 μM, respectively. In addition, the LOD and LOQ estimated from the standard deviation of the blank were 0.65 and 1.87 μM, respectively. Furthermore, this sensor was successfully applied to the detection of thiocyanate in urine samples from non-smokers and smokers. The results were in good agreement with the standard ion chromatography (IC) technique. This developed paper-based optode sensor was simple, low-cost, portable, and easy to use as a sensing device without any complicated instrument.

Preparation of QSS@AuNPs and Solvent Inducing Enhancement Strategy for Raman Determination of Salivary Thiocyanate.

Making the substrates form highly dense, homogeneous, and stable hotspots regions is important for the sensitive detection of surface-enhanced Raman spectroscopy (SERS). A new strategy based on solvent-induced (SI) SERS substrate to form a stable interval of the hotspot for detection was explored and the enhancement factor (EF) of our SERS substrates could reach about 1.4 × 109. By preferential adsorption of alcohol solutions by Q-Sepharose microsphere (QSS) in mixed water and alcohol solutions, the size of QSS@AuNPs was dynamically adjusted and the spacing between gold nanoparticles (AuNPs) was adjusted to keep the substrate in the optimal hotspot mode for the sensitive detection of SERS in the liquid state. As a real application case, such a SI-SERS strategy was employed to determine SCN- in saliva and a limit of detection (LOD) of about 10-10 M could be achieved.

3D Microfluidic Devices in a Single Piece of Paper for the Simultaneous Determination of Nitrite and Thiocyanate.

The concentrations of nitrite and thiocyanate in saliva can be used as the biomarkers of the progression of periodontitis disease and environmental tobacco smoke exposure, respectively. Therefore, it is particularly necessary to detect these two indicators in saliva. Herein, the three-dimensional single-layered paper-based microfluidic analytical devices (3D sl-μPADs) were, for the first time, fabricated by the spraying technique for the colorimetric detection of nitrite and thiocyanate at the same time. The conditions for 3D sl-μPADs fabrication were optimized in order to well control the penetration depth of the lacquer in a paper substrate. Then, the developed 3D sl-μPADs were utilized to simultaneously detect nitrite and thiocyanate and the limits of detection are 0.0096 and 0.074 mM, respectively. What is more, the μPADs exhibited good specificity, good repeatability, and acceptable recoveries in artificial saliva. Therefore, the developed 3D sl-μPADs show a great potential to determine nitrite and thiocyanate for the assessment of the human health.

Potentiometric Solid-Contact Ion-Selective Electrode for Determination of Thiocyanate in Human Saliva.

A new solid-contact potentiometric ion-selective electrode for the determination of SCN− (SCN-ISE) has been described. Synthesized phosphonium derivative of calix[4]arene was used as a charged ionophore. The research included selection of the ion-selective membrane composition, determination of the ISEs metrological parameters and SCN-ISE application for thiocyanate determination in human saliva. Preparation of the ISEs included selection of a plasticizer for the ion-selective membrane composition and type of the electrode material. The study was carried out using ISE with liquid internal electrolyte (LE-ISE) and solid-contact electrodes made of glassy carbon (GC-ISE) and gold rods (Au-ISE). The best parameters were found for GC sensors for which the ion-selective membrane contained chloroparaffin as a plasticizer (S = 59.9 mV/dec, LOD = 1.6 × 10−6 M). The study of potentiometric selectivity coefficients has shown that the thiocyanate-selective sensor could be applied in biomedical research for determination of SCN− concentration in human saliva. The accuracy of the SCN− determination was verified by testing 59 samples of volunteers’ saliva by potentiometric sensors and UV-Vis spectrophotometry as a reference technique. Moreover, SCN− concentrations in the smokers’ and non-smokers’ saliva were compared. In order to investigate the influence of various factors (sex, health status, taken medications) on the thiocyanate level in the saliva, more extensive studies on a group of 100 volunteers were carried out. Additionally, for a group of 18 volunteers, individual profiles of SCN− concentration in saliva measured on a daily basis for over a month were collected.

A Facile Cobalt (II) Tetra Amino Phthalocyanine Ingrained Poloy Aniline (PANI) Nano-fiber Film Layer Based Electrode Material for Amperometric Determination of Thiocyanate

This work describes the synthesis of tetra amino cobalt(II)phthalocyanine ingrained PANI nanofiber (TACoPc-PANI) and their characterization by spectroscopic and analytical techniques. The TACoPc-PANI thin film layer-based sensor was used for the determination of thiocyanate (SCN−) is reported in present work. We present PANI with tetra amino cobalt (II) phthalocyanine immobilized sensor in comparison with phthalocyanine thin film layer onto a sensing surface of glassy carbon electrode (GCE). The sensing of thiocyanate is done on tetra amino cobalt (II) phthalocyanine modified glassy carbon electrode (GCE/TACoPc) in the linear range (CV 0.2–10, CA 0.15–20 μmol L−1), sensitivity (CV 2.3523, CA 0.0457 μA μM−1 cm−2) and lower detection limit (CV 0.06, CA 0.05 µmol L−1) for better electrochemical studied TACoPc was ingrained with PANI nanofibers which increase the electron transferring ability and surface area of GCE, therefore sensing of thiocyanate as studied on GCE/TACoPc-PANI in the linear range of (CV 0.1–50, CA 0.05–50 μmol L−1), sensitivity (CV 1.0684, CA 0.017 μA μM−1 cm−2) and lower detection limit (CV 0.03, CA 0.017 µmol L−1) GCE/TACoPc-PANI ingrained modified sensor electrode shows good electrocatalytic activity than the modified electrode with TACoPc alone towards detection of thiocyanate molecules. The GCE/TACoPc-PANI shows good repeatability, stability and high selectivity even in the presence of an excess of thiosulfate, thiourea, sulfide.

A rapid method for simultaneous determination of nitrate, nitrite and thiocyanate in milk by CZE-UV using quaternary ammonium chitosan as electroosmotic flow inverter

This paper proposes a rapid method for the simultaneous determination of nitrate, nitrite and thiocyanate in different milk samples (cow, goat and soy) using capillary zone electrophoresis. The separations were conducted in a fused silica capillary dynamically coated with quaternary ammonium chitosan, with a total length of 48.5 cm (40 cm effective x 75 μm internal diameter) and direct detection in the UV region at 210 nm. The background electrolyte (BGE) was composed of 30 mmol L−1 of aminocaproic acid and 24 mmol L1 of perchloric acid (pH 3.85).A typical anodic electroosmotic flow of -31 × 10-9 m2 V−1 s−1 was observed at the pH of the separations. Bromate was used as the internal standard. The samples were injected by hydrodynamic pressure (50 mbar, 40 s) and the separation voltage was −30 kV. The proposed method was validated and presented good linearity (R2> 0.99) in the linear range of 0.1–4.0 mg L−1. The ranges of the limit of detection (LOD) and limit of quantification (LOQ) were 0.03-0.04 and 0.05–0.07 mg L−1, respectively. The intra-day and inter-day precision values were better than 4.2 and 8.7 %, respectively. Recovery values ranged from 85 to 104% for the different samples of milk. The proposed method was applied in 12 commercial samples with run times of less than 2 min. The good analytical performance indicates that the method proposed is a promising alternative for the determination of nitrate, thiocyanate and nitrite in milk samples.

Detection of Selenocyanate in Biological Samples by HPLC with Fluorescence Detection Using König Reaction

We developed a simple and sensitive HPLC method for the determination of selenocyanate (SeCN-). The König reaction, which is generally used for the determination of cyanide and thiocyanate, was applied for the post-column detection, and using barbituric acid as a fluorogenic reagent made it possible to detect SeCN- with high sensitivity. The limits of detection (LOD) and quantification (LOQ) were 73.5 fmol and 245.1 fmol, respectively. Subsequently, the amounts of SeCN- in human blood and in cultured cell samples were analyzed, and no SeCN- was detected in human whole blood. Interestingly, we have found that some of the spiked SeCN- decomposed to cyanide in human whole blood. Ascorbic acid suppressed the decomposition of SeCN- to cyanide by reducing the ferric ion, which is typically involved in SeCN- decomposition. Then, SeCN- was detected in cultured HEK293 cells exposed to selenite. The established HPLC method with fluorescence detection of SeCN- is useful for investigating small amounts of SeCN- in biological samples.

Development of a miniaturized photometer with paired emitter-detector light-emitting diodes for investigating thiocyanate levels in the saliva of smokers and non-smokers

A simple, small and inexpensive photometer that uses a pair of light-emitting diodes (LEDs) and a simple operational amplifier was developed for investigating thiocyanate levels in saliva obtained from smokers and non-smokers. The photometer is based on paired emitter-detector diodes (PEDDs), and the entire system can be purchased for less than a hundred US dollars. The PEDD-based photometer can measure the transmittance of a solution in a 1-cm disposable polystyrene cuvette using only rechargeable dry-cell batteries, which makes it suitable for analysis outside of equipped laboratories. The metal complex formation between Fe (III) and thiocyanate ions in an acidic condition permits colorimetric detection of thiocyanate ions using LEDs emitting at 465 nm, because the complex shows maximum absorption at 457 nm. The developed photometer exhibits excellent performance with linearity ranging from 0.05 mmol L−1 to 0.75 mmol L−1 and a correlation coefficient (r2) > 0.999. The limits of detection and quantification were 0.01 mmol L−1 and 0.05 mmol L−1, respectively. Both intra- and inter-day precision were obtained with relative standard deviations (RSD) of less than 1% in the determination of thiocyanate. The proposed method is simple, facile, and sensitive enough to investigate the levels of thiocyanate in the saliva samples of smokers and non-smokers with centrifugation being the only special treatment for samples. The results showed that the concentrations of thiocyanate were approximately 5-fold higher in smokers than in non-smokers.

Thiocyanate Determination using Technique of Flow Injection-Gas Diffusion Spectrophotometry with Cerium (IV)-Ninhydrin Reagent.

Numerous food plants contain thiocyanate, which can inhibit iodine uptake of thyroid gland and induce to the risk of iodine deficiency disorders (IDD). This research is focused on the development of new method for thiocyanate determination based on the formation of red hydrindantin using spectrophotometric flow injection (FI)–gas diffusion technique. In this technique, thiocyanate is oxidized by cerium (IV) in the acid donor stream to form hydrogen cyanide which diffuses through the membrane in the gas diffusion cell and reacts selectively with alkaline ninhydrin in the acceptor stream to form a red hydrindantin detected by spectrophotometer at 485 nm. The common operational conditions including sample volume, the length of mixing coil, and the flow rate as well as chemical parameters (concentration of cerium (IV) and ninhydrin, and pH reaction) were optimized with respect to sensitivity, analysis time, and linearity. The optimum condition notified by highest absorbance with sharp single peak and fast analysis was obtained under flow rate of 2 mL min−1, 300 µL sample volume, 75 cm mixing coil, 0.01 M cerium (IV), 1 % ninhydrin, and pH of 11. The interfering ions frequently exist with thiocyanate were also studied. Under the optimized conditions, the method showed linear for thiocyanate concentration from 5-30 mgL−1 and sampling rate of 120 s/h with a satisfactory reproducibility (RSD < 2% at n=3). This method has been successfully applied to determine thiocyanate in saliva from smoker and non-smoker and the results showed good agreement with those obtained from standard spectrophotometry method.

Kinetic-Spectrophotometric Determination of Thiocyanate in Human Saliva Based on Landolt Effect in Presence of Astrafloxine FF

In the present study a kinetic-spectrophotometric method for thiocyanate determination is described. The suggested method for the determination of thiocyanate is based on its "Landolt effect" on the reaction of bromate with hydrobromic acid, which leads to the formation of only one halogen bromine. The reaction was monitored spectrophotometrically at the maximum wavelength of astrafloxine FF light absorption at 535 nm. The absorbance of reactants mixture decreased with an increase of the reaction time. The calibration curve for thiocyanate determination was obtained in the concentration range of 0.03-2.0 μg mLμ1 under the optimal conditions (pH 1.5; CBrO3 - = 7.6 × 10-4 mol L-1; Castrafloxine FF = 1 × 10-5 mol L-1). The limit of detection was 0.01 μg mLμ1. The method was successfully applied to the determination of thiocyanate in human saliva samples with satisfactory results.

Simultaneous determination of cyanide and thiocyanate in swine plasma by high-performance liquid chromatography with fluorescence detection based on a novel D–π–A carbazole-based turn-on fluorescence labeling reagent

The goal of the current work was to develop a simple and sensitive high-performance liquid chromatography in combination with the fluorescence detection (HPLC-FLD) method for the fluorescence turn-on determination of cyanide and thiocyanate in swine plasma.