A highly sensitive NO2-selective optode membrane

Nezel, Tomas; Fakler, Alphons; Zhylyak, Gleb; Mohr, Gerhard J.; Spichiger‐Keller, Ursula E.

doi:10.1016/s0925-4005(00)00560-8

Cited by 12 publications

(9 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1). The detection process begins with the sorption of NO2(g) into the polymer membrane (1). In a second step NO2(m) reacts with the water molecule in the axial position of aquacyanocobalt(III)-cobyrinate perchlorate to form nitric and nitrous acid (2).…”

Section: Model Of the Reaction Mechanismmentioning

confidence: 99%

See 1 more Smart Citation

Aquacyanocobalt(III)-Cobyrinate as a Key Compound in NO2-Sensitive Polymeric Liquid Membranes

Nezel

Zhylyak

Mohr³

et al. 2003

ANAL. SCI.

Self Cite

View full text Add to dashboard Cite

Recently, an NO2-sensitive polymeric optode membrane based on an aquacyanocobalt(III)-cobyrinate derivative and a phenoxazine derivative has been introduced. 1 Optical microsensors based on this layer have been produced, characterized and shown to be suitable for application in fire detectors, exhibiting a detection limit of 15 ppb NO2. 2In this study the reaction mechanism which occurs within the NO2-sensitive membrane was investigated in detail. Reactions occurring within the membrane were characterized by determining the reaction products and by modifying the composition of the membrane.Since the polymer membrane only reflects the true situation in equilibrium with NO2 pressure, NMR and MS experiments were not feasible. Therefore, non-destructive investigations had to be performed on-line, during exposure to NO2. A suitable technique would be ATR FT-IR. However, using a commercial device it was found that the method is not sensitive enough to monitor species of interest within a polymeric membrane. In various experiments, though, it was possible to obtain the necessary information with UV/VIS-spectroscopy due to the fact that both membrane compounds are optically active.In sensor technology, the interactions between the interfering species and the sensitive layer have to be studied to specify the selectivity. Unlike sensor schemes which are based only on unspecific acid/base reactions, the sensing scheme proposed here comprises a selective step. The interaction of SO2 with the sensor membrane was investigated and compared with respect to the unique affinity of aquacyanocobalt(III)-cobyrinate for nitrogen dioxide, to characterize the proposed reaction mechanism. Experimental Membrane preparation and reagentsThe NO2-selective liquid polymeric membrane used in this study incorporated 0.13 to 2 weight% of aquacyanocobalt(III)-hepta(2-phenylethyl)cobyrinate perchlorate (nitrite-ionophore I, Fluka Chemie AG, Buchs). The chromoionophores used were ETH 5418 ([11-[(1-butylpentyl)oxy]-11-oxoundecyl-4-{[9-(dimethylamino)-5H-benzo[a]phenoxazine-5-ylidene]amino}-benzenate]) and ETH 7058 (2′,4′,5′,7′-tetraiodofluorescein octadecyl ester) in a concentration of 100 to 400 mol% relative to the cobalt complex. Poly(vinylchloride) (PVC) and DOS (bis(2-ethylhexyl)sebacate) as a plasticizer (Fluka Chemie AG, Buchs) were used as the matrix in a ratio of 1:2.ETH 7058 was synthesized from erythrosin extra bluish (Fluka) and 1-bromooctadecane (Fluka) and purified. 3 The product was further purified with flash chromatography (silica gel 60) using CH2Cl2/acetone/triethylamine (20/5/1) as the eluent. The fraction was treated with 0.01 M HCl and shaken. The organic phase was separated and washed three times with doubly distilled water and dried over MgSO4. After filtration and evaporation of the solvents, the precipitate was dissolved in chloroform and converted into potassium salt by exposure to 0.01 M KOH. Then, the organic phase was dried with MgSO4 and evaporated. The indicator salt obtained was dried at high vacuum.The synthesis of ...

show abstract

Section: Model Of the Reaction Mechanismmentioning

confidence: 99%

“…1 Optical microsensors based on this layer have been produced, characterized and shown to be suitable for application in fire detectors, exhibiting a detection limit of 15 ppb NO2. 2 In this study the reaction mechanism which occurs within the NO2-sensitive membrane was investigated in detail.…”

Section: Introductionmentioning

confidence: 99%

Aquacyanocobalt(III)-Cobyrinate as a Key Compound in NO2-Sensitive Polymeric Liquid Membranes

Nezel

Zhylyak

Mohr³

et al. 2003

ANAL. SCI.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, NO2 reacts also with various chemicals (e.g., volatile organic compounds) in the atmosphere under sunlight irradiation, to form other air pollutants such as suspended particulate matters and photochemical oxidants such as ozone, aldehydes, and peroxyacetyl nitrates, and these products also gave a serious risk to human health [4,5]. Therefore, numerous efforts have been so far directed to developing various types of NO2-sensing devices such as solid electrochemical [6][7][8], optical [9,10], and acoustic sensors [11,12]. Among them, it is well known that semiconductor gas sensors show relatively large sensitivity and excellent selectivity to NO2 at elevated temperatures, and SnO2 [13][14][15][16], In2O3 [17][18][19], WO3 [20][21][22][23], and the related materials are especially promising candidates as the NO2-sensing materials, among all the oxide semiconductors.…”

Section: Introductionmentioning

confidence: 99%

Semiconductor-type SnO2-based NO2 sensors operated at room temperature under UV-light irradiation

Hyodo

Urata

Kamada

et al. 2017

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

NO2-sensing properties of typical oxide (SnO2, In2O3, or WO3)-based semiconductor gas sensors were measured at 30°C with and without UV-light irradiation (main wavelength: 365 nm), and effects of noble-metal (Pd or Pt) loading, UV-light intensity (0-134 mW cm −2) and relative humidity in target gas (0-80%RH) on their NO2-sensing properties were investigated in this study. The UV-light irradiation effectively reduced the resistances of all sensors, enhanced their NO2 responses in some cases, and tended to accelerate their response and recovery speeds in dry air, because the UV-light irradiation promoted the adsorption and desorption of NO2-species on the surface. The SnO2 sensor showed the largest NO2 response in dry air, among all the pristine oxide sensors, especially under weak UV-light irradiation (≤ 35 mW cm −2), together with relatively fast response and recovery speeds. The Pd or Pt loading onto SnO2 enhanced the NO2 response of the SnO2 sensor and accelerated their response and recovery speeds in dry air, while XPS analysis indicated that most of the Pd and Pt nanoparticles loaded on the surface were oxidized after heat treatment at 500°C. Among all the sensors, the 0.05 wt% Pd-loaded SnO2 sensor showed the largest NO2 response under weak UV-light irradiation (≤ 35 mW cm −2), together with relatively fast response and recovery speeds. The addition of moisture to the target gas had adverse effects on the NO2 responses and the response speeds of the SnO2 and 0.05 wt% Pd-loaded SnO2 sensors, but the weak UV-light irradiation (7 mW cm −2) largely reduced the dependence of the NO2 response of the 0.05Pd/SnO2 sensor on relative humidity while maintaining the large NO2 response, probably because the weak UVlight irradiation promotes the desorption of physisorbed water molecules and then the effective adsorption of NO2 on the 0.05Pd/SnO2 surface.

show abstract

“…or chemical (covalent bond) methods [20]. Optodes are used based on different analytical techniques such as absorbance [21], fluorescence [22], or reflectance [18,19] the best of the authors' knowledge, only a few studies have been reported on the determination of nitrite based on optical sensors [23][24][25][26][27] using spectrophotometric measurement [23][24][25][26] and the quenching effect on chemiluminescence of CdSe [27]. Despite their advantages, all the optodes, however, suffer from the interference of oxalate and Fe(III) and from their inability to measure nitrite at concentrations below 5 ng mL −1 .…”

Section: Introductionmentioning

confidence: 99%

A highly selective optical sensor for catalytic determination of ultra-trace amounts of nitrite in water and foods based on brilliant cresyl blue as a sensing reagent

Ensafi¹,

Amini²

2010

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

A highly sensitive NO2-selective optode membrane

Cited by 12 publications

References 9 publications

Aquacyanocobalt(III)-Cobyrinate as a Key Compound in NO2-Sensitive Polymeric Liquid Membranes

Aquacyanocobalt(III)-Cobyrinate as a Key Compound in NO2-Sensitive Polymeric Liquid Membranes

Semiconductor-type SnO2-based NO2 sensors operated at room temperature under UV-light irradiation

A highly selective optical sensor for catalytic determination of ultra-trace amounts of nitrite in water and foods based on brilliant cresyl blue as a sensing reagent

Contact Info

Product

Resources

About