A vinyl acetate sensor based on cataluminescence on MgO nanoparticles

A novel cataluminescence (CTL) sensor using nanosized MgO as the sensing material for determination of the trace of vinyl acetate in air was proposed in the present study. Eight catalysts were examined and the results showed that the CTL intensity on MgO nanoparticles was the strongest. Under the optimized conditions, the linear range of the CTL intensity versus the concentration of vinyl acetate vapor was 2-2000 ppm with a detection limit of 1.0 ppm (3σ) and a relative standard deviation (R.S.D.) of 1.18% for five times determination of 1000 ppm vinyl acetate. There were no CTL emissions when foreign substances, including ammonia, benzene, acetic acid, formaldehyde and ethyl acetate, passed through the sensor. CTL emissions were detected for methanol, ethanol and acetaldehyde at levels around 5.5%, 10.1% and 13.4% compared with the responsed vinyl acetate. The sensor had a long lifetime more than 100 h.     

An ethanol sensor based on cataluminescence on ZnO nanoparticles

A novel gas sensor for the determination of ethanol was proposed in the present work, which was based on the generated cataluminescence emission from catalytic oxidation of ethanol on the surface of ZnO nanoparticles. The cataluminescence characteristics and the effect of different parameters on the signal intensity, such as morphology of synthesized ZnO, temperature and flow rate, were discussed in detail. Under the optimized experimental conditions, the calibration curve of cataluminescence intensity versus ethanol vapor concentration was linear in the range 1.0-100 ppm, and with a detection limit of 0.7 ppm (S/N = 3). Compared with the traditional electrical conductivity-based ZnO gas sensor for the determination of ethanol, the proposed ethanol sensor showed the advantages of high sensitivity, high selectivity and low working temperature.     

基于纳米ZnO-ZrO2催化发光丙酮传感器的研究

研究了丙酮在纳米ZnO-ZrO2(质量比为4:1)表面催化发光行为,发现基于这种纳米催化剂的气体传感器对丙酮的检测具有高灵敏度和较强的选择性。在波长460 nm,温度219℃,载气流速25 mL/min时进行定量分析,催化发光强度与丙酮浓度在一定范围内呈良好的线性关系,线性范围为0.1～4000 mL/m3(r=0.9996,n=6);检出限为1.6 mL/m3(S/N=3)。传感器工作时间可达106h以上,可用于丙酮的实时在线检测。     

A highly sensitive and selective dimethyl ether sensor based on cataluminescence

A sensor for detecting dimethyl ether was designed based on the cataluminescence phenomenon when dimethyl ether vapors were passing through the surface of the ceramic heater. The proposed sensor showed high sensitivity and selectivity to dimethyl ether at an optimal temperature of 279 °C. Quantitative analysis were performed at a wavelength of 425 nm, the flow rate of carrier air is around 300 mL/min. The linear range of the cataluminescence intensity versus concentration of dimethyl ether is 100-6.0 × 10³ ppm with a detection limit of 80 ppm. The sensor response time is 2.5 s. Under the optimized conditions, none or only very low levels of interference were observed while the foreign substances such as benzene, formaldehyde, ammonia, methanol, ethanol, acetaldehyde, acetic acid, acrolein, isopropyl ether, ethyl acetate, glycol ether and 2-methoxyethanol were passing through the sensor. Since the sensor does not need to prepare and fix up the granular catalyst, the simple technology reduces cost, improves stability and extends life span. The method can be applied to facilitate detection of dimethyl ether in the air. The possible mechanism of cataluminescence from the oxidation of dimethyl ether on the surface of ceramic heater was discussed based on the reaction products.     

A cataluminescence gas sensor for carbon tetrachloride based on nanosized ZnS

A novel and sensitive gas sensor was proposed for the determination of carbon tetrachloride based on its cataluminescence (CTL) by oxidation in the air on the surface of nanosized ZnS. The luminescence characteristics and the optimal conditions were investigated in detail. Under the optimized conditions, the linear range of the CTL intensity versus the concentration of carbon tetrachloride was 0.4-114 μg mL⁻¹, with a correlation coefficient (R) of 0.9986 and a limit of detection (S/N = 3) of 0.2 μg mL⁻¹. The relative standard deviation (R.S.D.) for 5.9 μg mL⁻¹ carbon tetrachloride was 2.9% (n = 5). There was no or weak response to common foreign substances including methanol, ethanol, benzene, acetone, formaldehyde, acetaldehyde, dichloromethane, xylene, ammonia and trichloromethane. There was no significant change of the catalytic activity of the sensor for 40 h over 4 days, with a R.S.D. of less than 5% by collecting the CTL intensity once an hour. The proposed method was simple and sensitive, with a potential of detecting carbon tetrachloride in environment and industry grounds. The possible mechanism was also discussed briefly.     

A new cataluminescence sensor for carbon tetrachloride using its catalytic reduction by hydrogen on palladium/carbon surface

A new cataluminescence (CTL) sensor was developed based on the chemiluminescence (CL) emission from the catalytic hydrodechlorination of carbon tetrachloride on the surface of palladium/carbon catalyst. The factors influencing the CTL signal, such as the catalyst, carrier gas, gas flow rate, temperature and the CL wavelength, were investigated in detail. Under the optimal conditions, the linear range of the CTL intensity versus concentration of carbon tetrachloride was 4.7–235 μg/mL (R = 0.9944, n = 7), with a limit of detection of 0.7 μg/mL (σ = 3). GC/MS results suggest that the possible CTL mechanism of the reduction is the formation of CCl₃ radicals. The CCl₃ radicals combine with H free atoms or capture hydrogen atoms from H₂ molecules to form excited CHCl₃ intermediates, which decay from the excited-state to the ground giving CTL emission for the detection. It is also found that some benzene derivatives with α-H of branched-chain, such as toluene, ethylbenzene and xylenecan, can play a role of catalyst in the reaction.     

A cataluminescence gas sensor based on nanosized V2O5 for tert-butyl mercaptan

This work proposed a gas sensor for the determination of tert-butyl mercaptan, one of the highly toxic volatile sulfur compounds, which was based on cataluminescence emission during its catalytic oxidation on the surface of nanosized V₂O₅. The cataluminescence characteristics and the optimum conditions, including the morphology of sensing material, the wavelength of cataluminescence emission, the oxygen flow rate and working temperature were investigated in detail. Under the optimized conditions, the calibration curve of the relative cataluminescence intensity versus the concentration of tert-butyl mercaptan vapor was made, with the linear range of 5.6-196 μg mL⁻¹ and the detection limit of 0.5 μg mL⁻¹ (S/N = 3). The relative standard deviation (R.S.D.) (n = 5) of relative cataluminescence intensity for 84 μg mL⁻¹ tert-butyl mercaptan was 3.6%. There is no or weak response to some common substances, such as formic acid, alcohol (methanol, ethanol, propanol, isopropanol, n-butanol, isoamyl alcohol), o-dichlorobenzene, acetonitrile, ethyl acetate, aldehyde (formaldehyde, acetaldehyde and propanal), 1,2-dichloroethane and ammonia. Furthermore, the proposed sensor was successfully used for determining tert-butyl mercaptan in four artificial samples, with a good recovery. The results demonstrated that the proposed gas sensor had a promising capability for the tert-butyl mercaptan in routine monitoring.     

A novel gaseous pinacolyl alcohol sensor utilizing cataluminescence on alumina nanowires prepared by supercritical fluid drying

A cataluminescence (CTL) sensor using Al₂O₃ nanowires as the sensing material was developed for the determination of trace pinacolyl alcohol in air samples based on the catalytic chemiluminescence (CL) of pinacolyl alcohol on Al₂O₃ nanowires. Eight catalysts were examined and the CL intensity on Al₂O₃ nanowires prepared by supercritical fluid drying was the strongest. This novel CL sensor showed high sensitivity and selectivity to gaseous pinacolyl alcohol at optimal temperature of 340 °C. Quantitative analysis was performed at a wavelength of 460 nm. The linear range of CTL intensity versus concentration of gaseous pinacolyl alcohol was 0.09 × 10⁻⁶ to 2.56 × 10⁻⁶ g mL⁻¹ (r = 0.9983, n = 6) with a detection limit (3σ) of 0.0053 × 10⁻⁶ g mL⁻¹. None or only very low levels of interference were observed while the foreign substances such as water vapor, ethanol, ammonia, chloroform, benzene, nitrogen dioxide, methylbenzene, hydrochloric acid, methanol and butanol were passing through the sensor. The response time of the sensor is less than 100 s, and the sensor had a long lifetime more than 60 h. The sensor would be potentially applied to analysis of the nerve agents such as Soman.     

A new cataluminescence gas sensor based on SiO2 nanotubes fabricated using carbon nanotube templates

In the present work, two morphologies of SiO₂ nanomaterials (SiO₂ nanotubes and nanoparticles) have been successfully synthesized in supercritical fluids (SCFs). The cataluminescence (CTL) features of the two SiO₂ nanomaterials to some common harmful gases were compared, and the results showed that SiO₂ nanotubes had better CTL sensing characteristic to some common harmful gases. The SiO₂ nanotubes not only had uniform size and shape with a high specific surface area, but also exhibited superior sensitivity and selectivity to ethyl acetate vapor. Using the SiO₂ nanotubes as sensing material, a CTL sensor for ethyl acetate vapor was developed. The proposed sensor showed high sensitivity and specificity to ethyl acetate at optimal temperature of 293 °C, a wavelength of 425 nm and a flow rate of 345 mL/min. With a detection limit of 0.85 ppm, the linear range of CTL intensity versus concentrations of ethyl acetate vapor was 2.0-2000 ppm. None or only very low levels of interference were observed while the foreign substances such as acetone, acetaldehyde, acetic acid, formaldehyde, ammonia, ethanol, benzene and methanol were passing through the sensor. This method allows rapid determination of gaseous ethyl acetate at workshop.     

A cataluminescence sensor for propionaldehyde based on the use of nanosized zirconium dioxide

A sensor is described for the detection of propionaldehyde in the gas phase. The sensing scheme is based on the blue cataluminescence (CTL) emission that results from the catalytic oxidation of propionaldehyde on the surface of nanosized zirconium dioxide. The sensor displays high sensitivity to propionaldehyde, a response time of 3 s, and a recovery time of 8 s. Under optimized conditions, the intensity of CTL is linearly related to the concentration of propionaldehyde in the 2.5–1,300 mg·m^?3 concentration range, with a limit of detection of 0.6 mg·m^?3 (at an SNR of 3) and a relative standard deviation (for n?=?6) of 2.2 % at a level of 80 mg·m^?3 of propionaldehyde. Relatively weak interference is observed for ethanol, acetone and acetaldehyde. The method was applied to analyze environmental air samples containing propionaldehyde, and data were compared with those obtained by GC-MS. The results were in good agreement, thereby indicating the utility of the sensor for routine monitoring. A possible mechanism for the catalytic oxidation of propionaldehyde on the ZrO₂ surface is discussed on the basis of the chromatograms of the reaction products.

基于分子印迹聚合物的化学发光传感器测定尿样中的甲福明

合成了甲福明的分子印迹聚合物,以此聚合物为识别物质,在线分离富集甲福明,建立了一种测定甲福明的流动式化学发光但感器。N-溴代丁二酰亚胺(NBS)和荧光素与甲福明发生化学反应,产生强的化学发光。甲福明质量浓度在2×10-8~8×10-6g/mL范围内同发光强度成良好线性关系,方法的检出限为6×10-9g/mL,相对标准偏差小于5%(n=9)。选择性实验表明将分子印迹聚合物作为识别物质应用于化学发光分析中,能大大提高化学发光分析方法的选择性。该传感器可逆性强、稳定性好,可重复使用100次以上,已用于人体尿样中甲福明的测定。     

A chemiluminescence array sensor based on graphene-magnetite-molecularly imprinted polymers for determination of benzenediol isomers

A chemiluminescence (CL) array sensor for determination of benzenediol isomers simultaneously using the system of luminol–NaOH–H₂O₂ based on a graphene-magnetite-molecularly imprinted polymer (GM-MIP) is described. Use of graphene in the GM-MIP thus prepared is helpful to improve the adsorption capacity, while use of magnetite nanoparticles can facilitate the isolation of GM-MIP at end of their synthesis, and rendering easier the use of the polymers in the array sensor. The adsorption performance and properties were characterized. The GM-MIP was used to increase the selectivity in CL analysis. In addition, the sensor was reusable and of good selectivity and adsorption capacity. The array sensor was finally used for the determination of hydroquinone, resorcinol and catechol in waste water samples simultaneously.     

BODIPY-based fluorometric sensor array for the highly sensitive identification of heavy-metal ions

A BODIPY(4,4-difluoro-4-bora-3a,4a-diaza-s-indacene)-based fluorometric sensor array has been developed for the highly sensitive detection of eight heavy-metal ions at micromolar concentration. The di-2-picolyamine (DPA) derivatives combine high affinities for a variety of heavy-metal ions with the capacity to perturb the fluorescence properties of BODIPY, making them perfectly suitable for the design of fluorometric sensor arrays for heavy-metal ions. 12 cross-reactive BODIPY fluorescent indicators provide facile identification of the heavy-metal ions using a standard chemometric approach (hierarchical clustering analysis); no misclassifications were found over 45 trials. Clear differentiation among heavy-metal ions as a function of concentration was also achieved, even down to 10⁻⁷ M. A semi-quantitative interpolation of the heavy-metal concentration is obtained by comparing the total Euclidean distance of the measurement with a set of known concentrations in the library.     

The recognition of beer with flow-through sensor array based on miniaturized solid-state electrodes

Flow-through electronic tongue based on miniaturized solid-state potentiometric sensors has been developed. A simple technique, i.e. membrane solution casting on the surface of the planar Au transducers was applied for the preparation of classical ion-selective and partially selective microelectrodes, introduced in the flow-through sensor array. The performance of the designed electronic tongue was tested in the qualitative analysis of various brands of beer. Samples of the same brand of beer but with different manufacture dates, originating from different manufacture lots, have been applied in the studies. The combination of PLS and ANN techniques allowed the discrimination between different brands of beer with 83% of correct classifications.     

Development of integrated chemiluminescence flow sensor for the determination of adrenaline and isoprenaline

A novel integrated chemiluminescence (CL) flow sensor for the determination of adrenaline and isoprenaline is developed based on the enhancing effect of analytes on CL emission of luminol oxidized by periodate in alkaline solution. The analytical reagents luminol and periodate are immobilized on anion exchange resins, respectively, and packed in a glass tube to construct a reagentless sensor. The proposed sensor allows the determination of adrenaline and isoprenaline over the range from 2.0×10⁻⁸ to 1.0×10⁻⁵ g ml⁻¹ and 2.0×10⁻⁷ to 5.0×10⁻⁵ g ml⁻¹, respectively. The detection limits are 7.0×10⁻⁹ g ml⁻¹ for adrenaline and 5.0×10⁻⁸ g ml⁻¹ for isoprenaline with a relative standard deviation of 1.7% for the 1.0×10⁻⁷ g ml⁻¹ adrenaline (n=11) and 2.1% for 1.0×10⁻⁶ g ml⁻¹ isoprenaline (n=11). The sample throughput was 60 samples h⁻¹. The sensor has been successfully applied to the determination of adrenaline and isoprenaline in pharmaceutical preparations.     

Method of gas mixtures discrimination based on sensor array, temporal response and data driven approach

This work presents a method of gas mixtures discrimination. The principal concept of the method is to apply measurement data provided by a combination of sensors at single time point of their temporal response as input of the discrimination models. The pattern data combinations are selected for classes of target gases based on the criterion of 100% efficient discrimination. Combinations of sensors and time points, which provide pattern data combinations in course or repeated measurements, are encoded in the form of addresses. The designer of sensor system is responsible for their selection and they are included in the software of the final instrument. The study of the method involved the discrimination of gas mixtures composed of air and single chemical: hexane, ethanol, acetone, ethyl acetate and toluene. Two sensor arrays were utilized. Each consisted of six TGS sensors of the same type. The dynamic operation of sensors was employed. As an example the stop-flow mode was chosen. The work provides the evidence of the existence of sensor combinations and time points, which are successful in discrimination of studied classes of target gases. The persistence of addresses was discussed considering the ability of sensor array to recognize analytes, variability of repeated measurement results, number of repeated measurements and a twin sets of sensors. Altogether, the validity of the method was demonstrated.     

一种新型催化发光传感器阵列用于化妆水的识别

采用3种纳米材料构建了一种新型的催化发光(CTL)传感器阵列,并测得10种化妆水在该传感器阵列上的CTL响应曲线.结果表明,不同化妆水在同一种纳米材料表面的CTL响应曲线存在差异;同一种化妆水在不同纳米材料表面的CTL响应曲线也不相同.通过动态时间规整算法(DTW)求算未知样的CTL响应曲线和化妆水模板CTL响应曲线之间的距离,建立三维坐标系,并检验DTW距离的限值,10种化妆水被正确识别.     

Chemiluminescence microfluidic system sensor on a chip for determination of glucose in human serum with immobilized reagents

A chemiluminescence (CL) biosensor on a chip coupled to microfluidic system is described in this paper. The CL biosensor measured 25×45×5 mm in dimension, was readily produced in analytical laboratory. Glucose oxidase (GOD) was immobilized onto controlled-pore glass (CPG) via glutaraldehyde activation and packed into a reservoir. The analytical reagents, including luminol and ferricyanide, were electrostatically co-immobilized on an anion-exchange resin. The most characteristic of the biosensor was to introduce the air as the carrier flow in stead of the common solution carrier for the first. The glucose was sensed by the CL reaction between hydrogen peroxide produced from the enzymatic reaction and CL reagents, which were released from the anion-exchange resin. The proposed method has been successfully applied to the determination of glucose in human serum. The linear range of the glucose concentration was 1.1-110 mM and the detection limit was 0.1 mM (3σ).     

A colorimetric sensor array for detection and identification of sugars

Molecular recognition of sugars and a practical method to detect and discriminate among a large number of such similar analytes remain substantial scientific challenges. We report here a low-cost, simple colorimetric sensor array capable of identification and quantification of sugars and related compounds. Fifteen different monosaccharides, disaccharides, and artificial sweeteners were differentiated without error in 80 trials. Limits of detection at pH 7.4 for glucose were <1 mM, which is below physiologically important levels.     

Dual-response colorimetric sensor array for the identification of amines in water based on supramolecular host-guest complexation

Amines have been found as a challenging compound class in previous works on chemical tongues. Herein, we describe the successful application of libraries based on host-guest inclusion complexes in cyclodextrins (CDs) and cucurbiturils (CBs) for the discrimination of primary, secondary, tertiary, aliphatic and aromatic as well as linear and branched amines in water. Besides the clear need for new detection, identification and quantification techniques of organic compounds in water, the main advantage of our approach is that an array made by combining six simple basic dyes with seven commercial organic capsules allows a perfect discrimination among 14 amines (see list in Table S1 in Supplementary data) with only very subtle structural differences.