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1.
PLoS One ; 15(2): e0228641, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053630

RESUMO

The use of plant tissue analysis as a tool for attaining low cyanogenic glucoside levels in cassava roots, has hardly been investigated. Just as the quality of crops is improved through the use of plant tissue analysis, the same can probably be done to consistently attain the lowest possible cyanogenic glucoside levels in cassava roots. High levels of cyanogenic glucosides in consumed fresh cassava roots or in their products have the potential of causing cyanide intoxication, hence the need to lower them. An experiment was thus conducted to assess the occurrence of meaningful relationships between plant nutritional status and cyanogenic glucoside production in cassava roots. Total hydrogen cyanide (HCN) levels in cassava roots were used to assess cyanogenic glucoside production. Using NPK fertiliser application to induce changes in plant nutritional status, the main objective of the study was investigated using the following sub-objectives; (1) to determine the effects of increased NPK fertiliser application on cassava root HCN levels; (2) and to show the occurrence of relationships between changes in nutrient levels in plant 'indicator tissue' and HCN levels in cassava roots. The study was a field experiment laid out as a split-plot in a randomized complete block design with three replicates. It was repeated in two consecutive years, with soil nutrient deficiencies only being corrected in the second year. The varieties Salanga, Kalinda, Supa and Kiroba were used in the experiment, while the NPK fertiliser treatments included; a control with no fertiliser applied; a moderate NPK treatment (50 kg N + 10 kg P + 50 kg K /ha); and a high NPK treatment (100 kg N + 25 kg P + 100 kg K /ha). A potassium only treatment (50 kg K/ha) was also included, but mainly for comparison. The root HCN levels of Salanga, Kalinda and Kiroba were significantly influenced by NPK fertiliser application in at least one of the two field experiments, while those of Supa remained uninfluenced. Changes in plant nutritional status in response to fertiliser application were thus shown to influence cyanogenic glucoside production. The results of the multiple linear regression analysis for the first field experiment, generally showed that the root HCN levels of some cassava varieties could have been 'reduced' by decreasing concentrations of nitrogen, potassium and magnesium in plants, or by improving plant calcium concentrations along with NPK fertiliser application. However, in the second field experiment (with corrected soil nutrient deficiencies) the regression analysis generally showed that the root HCN levels of some cassava varieties could have been 'reduced' by improving either one or a combination of the nutrients phosphorous, zinc and potassium in plants along with NPK fertiliser application. Although the results obtained in the two experiments had been contradicting due to slight differences in how they were conducted, the study had nonetheless demonstrated the occurrence of meaningful relationships between plant nutritional status and cyanogenic glucoside production; confirming the possible use of plant tissue analysis in predicting fertiliser needs for the consistent attainment of low cyanogenic glucosides in cassava roots.


Assuntos
Fertilizantes , Glucosídeos/análise , Cianeto de Hidrogênio/análise , Manihot/química , Nitrilos/análise , Raízes de Plantas/química , Agricultura , Produtos Agrícolas/química , Cianetos/análise , Glicosídeos/análise , Concentração de Íons de Hidrogênio , Modelos Lineares , Nitrogênio/análise , Fósforo/análise , Potássio/análise , Solo
2.
Environ Sci Pollut Res Int ; 27(8): 8176-8187, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31900767

RESUMO

The removal of cyanide compounds in soil by leaching was investigated in flask and column tests. All the experiments were conducted under alkaline conditions to prevent loss of hydrogen cyanide. Results showed that leaching progressed rapidly when the leaching temperature or the initial cyanide concentration was high. The obtained cyanide data in the flask test fitted an inner diffusion process, as described by a shrinking core model. In the batch column test, the cyanide concentration decreased from 44.06 to 9.86 mg/kg when the leaching intensity was 79 L/(m2 h) after 23.8 h leaching. The leaching process for the cyanide compounds was divided into two stages according to the batch column test despite the decrease in the leaching velocity as the cyanide concentration in soil declined. Cyanide removal in the batch column test was better than that in the flask test due to the higher gradient of cyanide concentration. The aqueous solution containing cyanide compounds was decomposed effectively by the hybrid process of ozone and UV rays. Furthermore, the leaching and decomposition of the soil and leaching wastewater were performed with a continuous column test with circulating leaching liquid. The cyanide compounds in the soil and wastewater were removed effectively.


Assuntos
Cianetos/análise , Poluentes do Solo , China , Cianetos/química , Solo , Águas Residuárias
3.
Mar Pollut Bull ; 150: 110770, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31910523

RESUMO

Ornamental fish have been legally harvested since the 1930's but in the 60's, cyanide fishing was first documented. Target fish exposed to the chemical are temporarily paralysed making them easier to catch, but with high post-capture mortality and significant ecological impacts, its use is banned in most exporting countries. To differentiate illegally caught fish from those sustainably collected, efforts to develop a post-collection detection test began nearly 30 years ago. However, even the most promising approach has been questioned by other researchers as unrepeatable under different experimental conditions. In this paper we summarise the evidence-base for establishing a cyanide detection test for live fish by evaluating current approaches. We describe the key knowledge gaps which continue to limit our progress in implementing a screening programme and highlight some alternative solutions which may provide greater short to medium term opportunities to prevent the illegal practise before fish enter the supply chain.


Assuntos
Cianetos/análise , Monitoramento Ambiental , Alimentos Marinhos , Poluentes Químicos da Água/análise , Animais , Pesqueiros/estatística & dados numéricos , Peixes
4.
Ecotoxicol Environ Saf ; 189: 110015, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31830602

RESUMO

This paper adopts a novel data-processing method of ECSA® based on TG/DSC-MS system to basically study the characteristics of release and conversion of fluorides and cyanides during heat treatment of the spent cathode carbon block (SCCB). All the experiments were conducted at 10 K⋅min-1 heating rate and under Ar or Ar-O2 atmospheres. The results indicate that the release of fluorides was just a steady but slow phase transition process under both Ar and Ar-O2 atmospheres, which can be comparatively accelerated when the carbon material was burnt. The cyanides were effectively decomposed at high temperature and at Ar-O2 atmosphere, with around three quarters of the cyanides being converted to the N2 and nearly a quarter being to the NO. Finally, analysis on the flue gas composition indicates that it had a more complicated composition of CO2, N2, NO, NO2, HCN under Ar-O2 atmosphere but only had a composition of CO2 and NO under Ar atmosphere.


Assuntos
Poluentes Atmosféricos/química , Carbono/química , Cianetos/química , Eletrodos , Fluoretos/química , Poluentes Atmosféricos/análise , Alumínio , Argônio/química , Atmosfera/química , Cianetos/análise , Fluoretos/análise , Temperatura Alta , Metalurgia , Eliminação de Resíduos
5.
Talanta ; 207: 120278, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594612

RESUMO

Cyanide is potentially hazardous and quickly acting chemical used in many fields of industry. Therefore, detection of cyanide is of main health concern due to its serious impacts on living organisms. In this context, we have developed rapid, low-cost and on-site sensory two molecules for the colorimetric and fluorogenic sensing of cyanide ion in aqueous samples and food samples. The prepared probes undergo distinct visual color change and exhibits selective fluorogenic turn-on or turn-off response towards cyanide. Competing anions have little or negligible effect on the detection of cyanide. The limit of detection for cyanide ion was calculated as low as 0.45 µM. Free receptors could be successfully regenerated by treating them with Ag+ ion. Moreover, a new visual colorimetric strip based on paper was fabricated with the pale yellow-to-pink color change signal. The fabricated test strips also demonstrated excellent selectivity towards cyanide ion without interfering possible fluoride and acetate ions. The smartphone-based technique which could directly read out the color value using a smartphone revealed an excellent potential for the cyanide detection without additional device.


Assuntos
Colorimetria/economia , Colorimetria/instrumentação , Custos e Análise de Custo , Cianetos/análise , Corantes Fluorescentes/química , Smartphone , Cianetos/química , Limite de Detecção , Modelos Moleculares , Conformação Molecular , Fitas Reagentes/química , Fatores de Tempo , Água/química
6.
Chemosphere ; 239: 124707, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31479912

RESUMO

Site soils with persistent cyanide compounds (primarily iron-cyanide complex) pose potential hazards to the environment and require remediation before redevelopment. This study evaluated the possibility of thermal treatment on remediation of cyanide-contaminated soils via batch heating experiments spanning a wide temperature range (200-500 °C). The change with operation variables of total cyanide and some reaction intermediates (e.g. CN-) was analyzed in order to elucidate the optimal variables that guarantee cyanide removal while generating no hazardous byproducts. Temperature, heating time and cyanide species have been found to be important parameters influencing removal/destruction of cyanide in soils. For soils bearing K3[Fe(CN)6] and K4[Fe(CN)6], a removal efficiency of >99.9% can be obtained with temperatures over 350 °C at 1 h, while for samples bearing Fe4[Fe(CN)6]3, a higher temperature (>450 °C) is needed to obtain an equivalent efficiency. During heating, the iron-cyanide complexes decomposed, releasing highly toxic free cyanides, which will subsequently be oxidized. However, a small percentage of free cyanide can always be detected as a result of incomplete oxidation, thus caution should be taken to minimize the accumulation of free cyanide during thermal treatment.


Assuntos
Cianetos/análise , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Temperatura , Cianetos/química , Poluição Ambiental/prevenção & controle , Ferrocianetos/análise , Ferrocianetos/química , Oxirredução , Poluentes do Solo/química
7.
Chem Commun (Camb) ; 55(100): 15137-15140, 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31789333

RESUMO

A fluorescent probe (TPA-BTD-MT) was designed to monitor cyanide ions (CN-) with a "turn-on" response, changing from "turn-off" behavior due to the structural change. TPA-BTD-MT exhibited high selectivity for sensing CN- in several food samples and was successfully used for imaging CN- in living cells and animals with strong "turn-on" fluorescence.


Assuntos
Cianetos/análise , Corantes Fluorescentes/química , Análise de Alimentos/métodos , Imagem Óptica , Compostos de Anilina/química , Animais , Linhagem Celular Tumoral , Limite de Detecção , Manihot/química , Manihot/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Fluorescência , Teoria Quântica , Solanum tuberosum/química , Solanum tuberosum/metabolismo
8.
J Fluoresc ; 29(6): 1401-1410, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31755047

RESUMO

A quantitative and qualitative fluorogenic molecular probe (R) has been designed and synthesized using Rhodamine-B hydrazide and 3,5-dibromo salicylaldehyde. The probe R has been applied for detection of ionic species and probe R turned out to be a prominent distinguisher among divalent and trivalent cations Al3+, Cr3+ and Fe3+ via the fluorometric response in acetonitrile medium. Colorimetric changes were observed for trivalent cations and Cu2+. Among all trivalent cations, Al3+ is possessing relay recognition for CN- even in the presence of other interfering anions with optimum precision. The association constant and the detection limit for R-Al3+ are 4.5 × 106 M-1 and 17.9 nM respectively. On the other hand, R + Al3++CN- exhibits an association constant and detection limit of 5.77 × 105 M-1 and 4.6 nM respectively. The stoichiometry of Al3+ binding with R is found to be 1:1. Quantum efficiency of probe R, R + Al3+ and R + Al3++CN- are found to be 0.2, 0.88 and 0.04 respectively. The receptor showed excellent real-time applicability for commercially available antiperspirant and apple seeds extract. The efficiency of the receptor further extended for fluorescent imaging of Al3+ and CN- in RAW264.7 cells.


Assuntos
Alumínio/análise , Cianetos/análise , Corantes Fluorescentes/química , Imagem Óptica , Animais , Cinética , Camundongos , Células RAW 264.7 , Espectrometria de Fluorescência
9.
Leg Med (Tokyo) ; 41: 101628, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31711010

RESUMO

Cyanide poisoning has been regarded to contribute the fatal outcome in fire victims. The toxicity of inhaled hydrogen cyanide (HCN) at the cellular level was evaluated considering the impact of methemoglobin (MetHb) produced by fire gases. Cyanide (CN) concentrations and total hemoglobin contents were measured in right heart blood (RHB) and seven organs/tissues (basal ganglia, brain stem, heart, lung, liver, kidney and psoas muscle) collected from 20 fire fatalities. MetHb and carboxyhemoglobin saturations were also measured in RHB. The amount of CN probably bound to the cytochrome c oxidase of the tissue cells (CCO-CN) was extrapolated from CN and hemoglobin contents in RHB and organs/tissues, MetHb saturation in RHB and binding capacity of MetHb for CN. CN concentrations in RHB showed a wide range with the highest concentration of 8.927 µg/mL. The lung contained the largest CN content among organs/tissues with the mean concentration of 2.219 µg/g, then the heart (0.259 µg/g) and it was lower than 0.100 µg/g in others. Exceedingly large amount of CN in the lung could be explained by high hemoglobin content, being the port of entry of HCN and postmortem diffusion of fire gases. CCO-CN was theoretically present in about 20% of organ/tissue samples, most commonly in the basal ganglia (10 samples, with the mean of 0.059 µg/g) followed by heart (eight samples, with the mean of 0.109 µg/g). No CCO-CN was found in liver and kidney. HCN might have the effect on brain and heart.


Assuntos
Cianetos/análise , Fogo , Adulto , Idoso , Idoso de 80 Anos ou mais , Gânglios da Base/química , Tronco Encefálico/química , Carboxihemoglobina/análise , Feminino , Medicina Legal , Hemoglobinas/análise , Humanos , Rim/química , Fígado/química , Pulmão/química , Masculino , Metemoglobina/análise , Pessoa de Meia-Idade , Miocárdio/química , Músculos Psoas/química , Adulto Jovem
10.
Analyst ; 144(21): 6422-6431, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31584578

RESUMO

Herein, a colorimetric sensor (L) based on a naphthyl derivative bearing hydrazone receptors was synthesized via a one-step reaction process, and its recognition properties towards biologically important anions in an acetonitrile-water mixture were investigated by naked-eye observation and UV-Vis and 1H NMR spectroscopy. The molar addition of anions, such as TBAF-, TBAOH-, TBACN- and TBAAcO-, induced a significant red shift in the charge transfer band (Δλ = 73 nm, from 337 nm to 410 nm), in agreement with visible "naked eye" detectable colorimetric activities; in addition, soaked-in-L paper strips were prepared, which could significantly discriminate cyanide (KCN) and hydroxide (NaOH) ions dissolved in tap water via the litmus test method. This study was complemented by density functional theory computations to gain more insight into the interaction between L and anions.


Assuntos
Colorimetria/métodos , Cianetos/análise , Água Potável/química , Hidróxidos/análise , Cianetos/química , Teoria da Densidade Funcional , Hidrazonas/química , Hidróxidos/química , Modelos Moleculares , Conformação Molecular , Fatores de Tempo
11.
Chemistry ; 25(62): 14214-14222, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31452291

RESUMO

A series of new ruthenium(II) vinyl complexes has been prepared incorporating perylenemonoimide (PMI) units. This fluorogenic moiety was functionalised with terminal alkyne or pyridyl groups, allowing attachment to the metal either as a vinyl ligand or through the pyridyl nitrogen. The inherent low solubility of the perylene compounds was improved through the design of poly-PEGylated (PEG=polyethylene glycol) units bearing a terminal alkyne or a pyridyl group. By absorbing the compounds on silica, vapours and gases could be detected in the solid state. The reaction of the complexes [Ru(CH=CH-PerIm )Cl(CO)(py-3PEG)(PPh3 )2 ] and [Ru(CH=CH-3PEG)Cl(CO)(py-PerIm )(PPh3 )2 ] with carbon monoxide, isonitrile or cyanide was found to result in modulation of the fluorescence behaviour. The complexes were observed to display solvatochromic effects and the interaction of the complexes with a wide range of other species was also studied. The study suggests that such complexes have potential for the detection of gases or vapours that are toxic to humans.


Assuntos
Monóxido de Carbono/análise , Cianetos/análise , Corantes Fluorescentes/química , Imidas/química , Nitrilos/análise , Perileno/análogos & derivados , Rutênio/química , Alquinos/química , Monóxido de Carbono/toxicidade , Complexos de Coordenação/química , Cianetos/toxicidade , Nitrilos/toxicidade , Perileno/química , Piridinas/química
12.
Environ Sci Pollut Res Int ; 26(27): 27854-27861, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342349

RESUMO

In this paper, a flexible and efficient nano-reinforced polymer inclusion membrane (PIM) was fabricated and used for cyanide (CN-) extraction from water samples. Aliquat 336 (a liquid anion exchanger) was embedded in poly(vinyl chloride) (PVC) support as the extractant. Mg-Al-CO3 layered double hydroxide (LDH) with high surface area and anion exchange ability was applied to promote the extraction efficiency of PIM. A PIM comprising 56% PVC, 40% Aliquat 336, and 4% Mg-Al-CO3 LDH showed the best extraction efficiency. A single beam ultraviolet-visible spectrophotometer was used for the detection of cyanide. Surface morphology of the PIM was studied by field emission scanning electron microscopy. The experimental parameters influencing the extraction process were investigated and optimized. The intra- and inter-day relative standard deviations at two different concentrations were in the range of 2.8-7.6%. The dynamic range of the method was in the range of 5-500 µg L-1, and the detection limit was 1.4 µg L-1. The LDH reinforced PIM showed proper characteristics for the extraction of cyanide from real water and wastewater samples with recoveries between 82 and 115%.


Assuntos
Hidróxido de Alumínio/análise , Cianetos/análise , Hidróxidos/análise , Magnésio/análise , Hidróxido de Alumínio/química , Cianetos/química , Hidróxidos/química , Limite de Detecção , Magnésio/química , Microscopia Eletrônica de Varredura , Polímeros , Águas Residuárias , Água
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 221: 117172, 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31174138

RESUMO

A new quinone-benzothiazole imine based chemodosimeter (R) was rationally designed, synthesized and characterized using NMR and mass spectral techniques. The receptor colorimetrically senses cyanide in aq. HEPES buffer: DMF (2:8 v/v) solution with an instantaneous colour change from yellow to bluish green. An enhancement of fluorescence intensity at 429 nm with excimer formation is also observed after addition of cyanide to the receptor, which is accompanied with a colour change from yellow to blue under UV lamp. Nucleophilic addition of cyanide to imine C-atom inhibits intra-molecular charge transfer (ICT) transition, which is responsible for the excimer formation. This chemical reaction is confirmed by 1H NMR titration. The receptor binds with two equivalents of cyanide with a binding constant of 5.55 × 104 M-1. The limit of detection (LOD) of cyanide by the receptor is found to be as low as 69 nM, which is much lower than the acceptable limit of cyanide in drinking water as set by the WHO (1.9 µM). Electrochemical studies support the termination of ICT transition upon addition of cyanide ion. Theoretical studies substantiate experimental findings and excimer formation. The receptor fluorometrically detects cyanide present in tap water and food materials such as cassava flour, almond and potato.


Assuntos
Colorimetria/métodos , Cianetos/análise , Corantes Fluorescentes/química , Análise de Alimentos/métodos , Benzotiazóis/química , Cianetos/química , Técnicas Eletroquímicas , Farinha/análise , Corantes Fluorescentes/síntese química , Água Doce/análise , Limite de Detecção , Espectroscopia de Ressonância Magnética , Manihot/química , Prunus dulcis/química , Solanum tuberosum/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Poluentes Químicos da Água/análise
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 222: 117157, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31203052

RESUMO

New azo-azomethine sensor, HL, has been synthesized and characterized using standard spectroscopic methods. HL was found to sense CN- and AcO- in DMSO and semi-aqueous media over other anions such as F-, Cl-, Br-, I-, H2PO4- and HSO4-. The anions recognition ability of HL was also evaluated using UV-Vis absorption and 1H NMR spectroscopy. Importantly, HL can detect CN- and AcO- in DMSO even at 0.7 ppm and 1.3 ppm, respectively. The binding stoichiometry between HL and the mentioned anions was found to be 1:1 with binding constants of 8.81 × 103 M-1 and 3.64 × 104 M-1 for CN- and AcO-, respectively. Successfully, HL was used for the detection of sodium diclofenac over the other opiate drugs such as codeine phosphate, noscapine hydrochloride, papaverine hydrochloride, and morphine sulfate. The designed chemosensor has also shown highly promising results for the qualitative and quantitative detection of sodium diclofenac in oral pills.


Assuntos
Ânions/análise , Anti-Inflamatórios não Esteroides/análise , Compostos Azo/química , Corantes/química , Cianetos/análise , Diclofenaco/análise , Tiossemicarbazonas/química , Colorimetria/métodos , Limite de Detecção , Comprimidos
15.
PLoS One ; 14(5): e0216708, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31083702

RESUMO

Soils in areas affected by konzo (a cassava cyanide intoxication paralytic disorder) are predominantly infertile and probably unable to supply cultivated cassava with the nutrients it needs to achieve optimal growth. Soil nutrient supply in these areas could also be influencing cyanogenic glucoside production in cassava, however there is hardly any knowledge on this. An assessment of soil nutrient levels on crop fields in konzo-affected areas was therefore carried out to determine their adequacy for optimal cassava growth. Konzo-affected Mtwara region of Tanzania, was used as a case study. Whether soil nutrient supply influences cyanogenic glucoside production in cassava cultivated in konzo-affected areas and how it could be doing this, was additionally investigated. To investigate this, correlations between total hydrogen cyanide (HCN) levels (a measure of cyanogenic glucoside content) in cassava roots and various soil nutrient levels on crops fields were carried out. This was followed by an investigation of relationships between cases of cassava cyanide intoxication and soil nutrient levels on crop fields from which the consumed toxic cassava roots had been harvested. Cases of cassava cyanide intoxication were used as a proxy for high cyanogenic glucoside levels in cassava roots. Logistic regression analysis was used in the latter investigation. Other important non-nutrient soil chemical characteristics, like pH and soil organic carbon, were also included in all analysis performed. The results revealed that most soil nutrients known to have reducing effects on cassava cyanogenic glucosides, like potassium (mean = 0.09 cmol/kg, SD = 0.05 cmol/kg), magnesium (mean = 0.26 cmol/kg, SD = 0.14 cmol/kg) and zinc (mean = 1.34 mg/kg, SD = 0.26 mg/kg) were deficient on several crop fields. The results also showed that cyanogenic glucosides in cassava roots could be increased with the increased supply of sulphur in soils in bitter cassava varieties (rs = 0.593, p = 0.032), and with the increased supply of P in soils in all cassava varieties (rs = 0.486, p = 0.026). The risk of cassava cyanide intoxication occurring (and thus high cyanogenic glucoside levels in cassava) was found to be likely increased by cultivating cassava on soils with high pH (X2 = 8.124, p = 0.004) and high iron (X2 = 5.740, p = 0.017). The study managed to establish that cassava grows under conditions of severe nutrient stress and that soil nutrient supply influences cyanogenic glucoside production in cassava cultivated in konzo-affected areas of Mtwara region. Despite the multiple soil nutrient deficiencies on crop fields, low soil fertility was however not the only probable cause of increased cyanogenic glucosides in cassava, as high soil nutrient levels were also found to be potential contributors.


Assuntos
Glicosídeos/análise , Manihot/crescimento & desenvolvimento , Solo/química , Carbono/análise , Cianetos/análise , Glucosídeos/análise , Glicosídeos/metabolismo , Concentração de Íons de Hidrogênio , Manihot/metabolismo , Nutrientes/metabolismo , Raízes de Plantas/química , Potássio/análise , Tanzânia , Tiocianatos/análise
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 297-306, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31051424

RESUMO

A simple selective colorimetric and fluorimetric chemosensor RD based on Rhodamine B hydrazone derivatives was designed and synthesized, which showed both colorimetric and fluorescence responses for cyanide and Cu2+ in aqueous solution with specific selectivity and high sensitivity. In the presence of cyanide, the sensor exhibited a visible color change from colorless to pale yellow by naked-eyes and rapidly produced a strong yellow fluorescence in aqueous solution. The detection limit on fluorescence response of RD sensor to CN- is down to 3.54×10-7M. In addition, compared to other metal ions such as Fe3+, Hg2+, Ag+, Ca2+, Cu2+, Co2+, Ni2+, Cd2+, Pb2+, Cr3+, Zn2+ and Mg2+ in aqueous solutions, RD could show both colorimetric and fluorescence responses rapidly for Cu2+. Notably, this sensor can be used as a molecular switch controlled by CN- and H+ cyclically. Test strips based on RD were fabricated that could be used as a convenient and efficient CN- and Cu2+ test kits. RD could detect cyanide in germinated potato, bitter almond and tap water. This chemosensor enabled detection of two ions, which do not need to rely on two different sensors.


Assuntos
Cobre/análise , Cianetos/análise , Corantes Fluorescentes/química , Rodaminas/química , Colorimetria/métodos , Hidrazonas/química , Limite de Detecção , Prunus dulcis/química , Solanum tuberosum/química , Espectrometria de Fluorescência/métodos , Água/análise
17.
Anal Sci ; 35(7): 821-825, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31105086

RESUMO

We describe the bioluminescence of a genetically engineered Escherichia coli harboring a recombined plasmid with a catalase gene promoter fused lux gene cluster, responsible for the generation of photons closely associated with respiratory inhibition, with the aim of applying it for cyanide sensing. This E. coli construct was favorably utilized for the microplate assay of cyanide by leveraging the microenvironment of the biocompatible alginate. The brightness of the bioluminescence, induced by cyanide stimulation of the respiration causative of the production of hydrogen peroxide, positively correlates with its concentration. Moreover, visualization of cyanide with a consumer digital camera, ranging in concentration from about 0.01 mg CN·L-1 in the alginate sol to around 100 mg CN·L-1 in its gel, was attained.


Assuntos
Alginatos/química , Técnicas Biossensoriais/métodos , Cianetos/análise , Escherichia coli/genética , Engenharia Genética , Medições Luminescentes/métodos , Plasmídeos/genética , Células Imobilizadas/química , Escherichia coli/química , Escherichia coli/citologia , Luz
18.
Anal Chim Acta ; 1065: 113-123, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31005143

RESUMO

A new highly selective and sensitive dual-mode sensor 3TD based on the conjugate of oligothiophene and barbituric acid moiety was developed for colorimetric and turn-on fluorescent detection of CN─. The sensor 3TD exhibited high specificity towards CN─ by interrupting its own ICT producing thereupon a large blue-shift in UV-Vis spectrum and remarkable "turn-on" fluorescence emission. The detection limit was 2.26 × 10─7 M, which is quite lower than the permissible level of CN─ in drinking water according to the WHO. The fluorescent detection of CN─ was well demonstrated by filter paper strips and silica coated TLC plates. Moreover, the sensor was also used to detect CN─ in environmental water and agro-products with satisfactory results. Most importantly, in terms of these advantages of colorimetric and turn-on fluorescent dual-mode, immediate response, excellent selectivity, high sensitivity, low cytotoxicity, and good biocompatibility, the sensor 3TD was successfully applied into CN- imaging in living cells, demonstrating its excellent value in practical application.


Assuntos
Barbitúricos/química , Colorimetria , Cianetos/análise , Corantes Fluorescentes/química , Tiofenos/química , Barbitúricos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Células HeLa , Humanos , Estrutura Molecular , Imagem Óptica , Papel , Teoria Quântica , Dióxido de Silício/química , Espectrometria de Fluorescência , Relação Estrutura-Atividade , Tiofenos/farmacologia , Água/química
19.
Methods Appl Fluoresc ; 7(2): 025003, 2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30822766

RESUMO

A naphthoquinone-imine based fluorescent probe (R) has been synthesized and characterized by NMR and mass spectral techniques. The receptor shows high selectivity towards cyanide in water in the presence of other competitive anions with an instantaneous colour change from non-emissive to green under UV light. The turn-on fluorescence is due to deprotonation of three hydroxyl groups by cyanide ions as evidenced from 1H NMR titration experiment. The LOD of cyanide by R in water is 0.6 µM, which is much lower than the permissible limit of cyanide in drinking water according to the WHO.


Assuntos
Cianetos/análise , Água Potável/análise , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Naftoquinonas/química , Poluentes Químicos da Água/análise , Cor , Colorimetria/métodos , Teoria da Densidade Funcional , Corantes Fluorescentes/síntese química , Iminas/síntese química , Iminas/química , Limite de Detecção , Manihot/química , Modelos Químicos , Naftoquinonas/síntese química , Prunus dulcis/química
20.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1110-1111: 36-42, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30776613

RESUMO

Cyanide (CN) is the biomarker of exposure to the components of tobacco smoke, although its presence in biological samples is also due to the consumption of products containing cyanogenic glycosides. In this work, we determine the concentration of the free cyanide in urine, saliva and breast milk matrices, using ion chromatography with pulsed amperometric detection (IC-PAD). IC-PAD is an emerging method, with only few documented applications in urine and saliva, and the presented determination in breast milk is its first published report for any method. The biological samples, which were obtained from women staying in a maternity ward, showed cyanide concentrations spanning 1.82-98.47 µg L-1. Under the optimized chromatographic conditions, the IC-PAD system exhibited satisfactory repeatability (R < 3%, n = 3) and good linearity in the range of 1-100 µg L-1. Thus, it proved to be an effective tool for monitoring trace cyanide concentration in a series of human body fluid matrices, including breast milk. This last matrix is especially important due to the possible effect on infant health related to the mothers' smoking habits.


Assuntos
Cromatografia por Troca Iônica/métodos , Cianetos/análise , Exposição Ambiental/análise , Leite Humano/química , Adulto , Feminino , Humanos , Limite de Detecção , Modelos Lineares , Gravidez , Reprodutibilidade dos Testes , Fumaça/análise , Fumar , Adulto Jovem
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