纳米MgO催化发光检测硫化氢

研究了硫化氢在纳米Mg O表面的催化发光现象,发现纳米Mg O对硫化氢具有较好的特异性,据此设计了硫化氢催化发光传感器。通过优化设计建立了一种快速检测硫化氢的新方法,线性范围为2.00~200ppm(r=0.999 3),检出限为0.8 ppm(信噪比S/N=3)。采用此传感器进行人工合成样品中硫化氢的加标回收分析,回收率为88.4%~97.2%。此传感器具有灵敏、快速、操作简便等优点,在硫化氢快速检测领域具有潜在应用前景。该文还探讨了硫化氢的催化发光反应机理。     

基于酶催化银沉积质量放大的血吸虫压电免疫传感器的研究

发展了一种基于酶催化金属银沉积信号放大的新型高灵敏气相压电免疫传感检测技术.先将血吸虫抗原(SjAg)共价固定在石英晶体表面,制备得到血吸虫压电免疫传感器.检测时,在晶振上滴加不同浓度的待测血吸虫抗体,再将碱性磷酸酶标记的二抗通过夹心方式结合到传感器表面.然后利用碱性磷酸酶催化磷酸化的抗坏血酸酯水解从而还原硝酸银,使金属银沉积在晶振表面上,放大传感器的质量响应信号.实验结果表明该传感检测方法可显著提高气相压电免疫传感器的检测灵敏度,传感器对血吸虫抗体的响应线性范围在1～225 ng/mL,检测下限为1 ng/mL.     

基于纳米Co3O4低温催化发光的乙醚传感器

基于纳米Co3O4材料上乙醚的催化发光(CTL)现象,建立了直接测定空气中乙醚浓度的方法.研究发现,在较低温度下,乙醚在球链状的纳米Co3O4表面具有很高的发光强度和较好的选择性,以此为敏感材料就可以建立一种高效稳定的乙醚气体传感器.其最佳操作条件为:测定温度176℃,分析波长440 nm,载气流速180 mL/min.乙醚气体在4.0～1500 ppm(φ)的浓度范围内呈良好的线性关系(R=0.9993),响应时间为2 s,检出限为φ=1.67 ppm(3σ),回收率为97.3%～103.0%.考察了11种相同浓度的常见挥发性有机物的干扰情况,发现除丙酮、乙醇、四氯化碳和乙酸乙酯有轻微干扰(小于0.8%),其余7种物质均未产生明显的CTL信号.连续140 h通过150 ppm(φ)的乙醚气体,发光强度无明显降低,表明该传感器是一种长寿命的、性能稳定的传感器.     

基于四氧化三钴材料催化发光的丙醛气体传感器研究

研究发现, 在一定条件下丙醛气体在四氧化三钴材料表面上具有催化发光特性,基于此建立了一种检测空气中痕量丙醛气体的催化发光传感器.在对合成的3种形貌四氧化三钴的催化发光性质进行比较的基础之上,对分析方法条件进行了优化,其结果表明:在以微球状四氧化三钴作为传感材料,检测波长490 nm, 反应温度232 ℃,载气流速400 mL/min的最优条件下,可测定的丙醛气体浓度的线性范围为0.3～171 mg/L(r=0.9977, n=13),检出限为0.1 mg/L(S/N=3),测定4.8 mg/L丙醛的相对标准偏差为1.8%(n=5).此外,考察了相同浓度的常见挥发性有机物的干扰情况,其结果表明该传感器具有很好的选择性.连续80 h通过4.8 mg/L丙醛,发光强度无明显降低,相对标准偏差小于5%,表明此传感器使用寿命长.并将该传感器成功用于人工合成样品的分析,回收率在91%～103%之间,测定浓度值与实际组成基本相符.     

电化学发光传感器在农业传感领域中的研究进展

基于电化学发光(ECL)分析法构建的电化学发光传感器具有灵敏度高、背景信号低、操作简单的优点,因此,它在农业、工业、环境、临床和食品等领域具有广泛的应用前景。 本文主要综述了电化学发光传感器检测农药残留和真菌毒素的应用及其相应的检测性能,分析了电化学发光传感器在农业传感领域的研究现状,并阐述了未来电化学发光传感器的发展趋势。     

基于丝网印刷电极的甲胎蛋白电化学免疫传感器

报道了一种基于金纳米粒子(AuNPs)双重信号放大的高灵敏电化学免疫传感器,并应用于肝癌标志物甲胎蛋白(AFP)的检测。通过在丝网印刷电极(SPE)表面电沉积AuNPs提高电极的重现性,利用AuNPs的吸附作用固定AFP抗体,用于捕获样品中的待测AFP抗原,并进一步与固定了辣根过氧化物酶(HRP)标记检测抗体的纳米金免疫探针发生特异性结合,所形成的夹心免疫复合物可以催化底物得到响应电流。用扫描电镜(SEM)和微分脉冲伏安法(DPV)等技术研究电极组装过程以及电极的化学性质,讨论了影响免疫传感器性能的因素。在最优实验条件下,传感器的峰电流信号与AFP浓度在2.5~30ng/mL范围内呈良好的线性关系,检出限为0.16ng/mL。该传感器具有灵敏度高、成本低、仪器体积小的优点,具有较好的应用前景。     

树枝状硅钛杂化纳米球的制备及乙醚催化发光性能研究

采用两步后接枝法制备了树枝状硅钛杂化纳米球(DMSTNs),将DMSTNs均匀涂覆于陶瓷加热棒表面构建了一种新型乙醚催化发光传感平台。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、电感耦合等离子体发射光谱(ICP-OES)、傅里叶红外光谱(FT-IR)以及N₂吸附-解吸曲线对DMSTNs的形貌、结构、晶型、化学组成、孔体积、比表面积等进行表征,并讨论了乙醚在DMSTNs催化剂表面的催化发光机理。在优化条件下(440 nm吸收波长、380℃反应温度、270 mL/min载气流速),乙醚传感器催化发光强度与乙醚浓度在10～45 mmol/L范围内有良好的线性关系(R²=0.9933),检出限为4 mmol/L,相对标准偏差RSD为2.4%(S/N=3)。     

纳米In_2O_3催化发光传感器快速检测三氯乙烯

本文以纳米In_2O_3为传感元件,设计构建了快速检测三氯乙烯的催化发光传感器。该传感器对三氯乙烯具有灵敏度高、特异性好及响应快速等优点。在检测波长为440nm,工作温度为250℃条件下,催化发光信号强度与三氯乙烯浓度呈良好的线性关系,其线性范围为20~1 200mg/m~3(r=0.9984),检出限(S/N=3)为8.0mg/m~3。苯、甲苯、邻二甲苯、对二甲苯、间二甲苯、氨水、甲醇、乙醇、甲醛、乙醛、四氯化碳、甲酸、乙酸、乙酸乙酯、正己烷及环己烷经过此传感器时,只有乙醇产生弱的发光信号,其它物质不产生响应信号。在72h内24次测定100mg/m~3的三氯乙烯,所得相对标准偏差小于5.0%,表明传感器稳定性好,使用寿命长。将此传感器用于三氯乙烯的分析,加标回收率为93.2%~103%。     

基于丝网印刷碳纳米管电极的电化学传感检测有机磷农药

采用商品化丝网印刷碳纳米管电极(CNTSPE),并利用层层组装技术将乙酰胆碱酯酶(AChE)、聚二烯丙基二甲基氯化铵(PDDA)逐层依次修饰于CNTSPE表面,制备了PDDA/AChE/PDDA/AChE/PDDA修饰的CNTSPE传感器(PDDA/(AChE/PDDA)_2/CNTSPE),并以对氧磷、毒死蜱为研究模型,考察了该电化学传感器的性能并建立了对氧磷、毒死蜱的电化学传感检测方法。结果表明,电极对氧磷、毒死蜱两种农药的线性响应范围分别为50～150 ng/mL,20～150 ng/mL,检测限分别为20 ng/mL,10 ng/mL。该传感器应用于实际样品中目标农药的检测,回收率在87. 5%～90. 6%之间。     

复合ZrO2/MgO催化发光丙烯醛气体传感器

设计了基于在纳米ZrO2中掺杂Mg0的催化发光传感器,以快速检测丙烯醛气体.与纯ZrO2相比,MgO的掺杂量为5%时,丙烯醛的催化发光强度增大了1.8倍,干扰气体乙醛的催化发光强度降为原来的约1/7.传感器在波长425 nm,温度279 ℃,流速200 mL/min条件下,对丙烯醛具有高灵敏度和选择性,发光强度与丙烯醛...     

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.     

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 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.     

基于CeO2-Co3O4纳米纤维的催化发光式甲醛传感器研究

采用双喷嘴静电纺丝法制备了CeO2-Co3 O4纳米纤维,将制备的CeO2-Co3 O4纳米纤维均匀涂覆于 ω型加热线圈表面形成催化发光薄膜,设计了一种新型催化发光甲醛传感器.采用X射线衍射仪、 扫描电子显微镜、 全自动程序化学吸附仪和X-射线光电子能谱仪,表征了Co3 O4-CeO2纳米纤维的相组成和微观形貌,讨论了甲醛在CeO2-Co3 O4催化剂表面的电化学特性和催化发光机理.在优化条件下,即波长500 nm、 温度550℃ 、 载气流速0.2 L/min,甲醛传感器件(Ce30)催化发光强度与甲醛浓度在1.2~50μg/m3范围内有良好的线性关系,灵敏度为40.04 a.u./(μg/m3),检出限为1.2μg/m3,动态响应和恢复时间分别为2.4和3.5 s.此传感器可用于汽车尾气中甲醛浓度检测,相对误差范围为0.4%~1.1%,相对标准偏差RSD<3%(n=6).     

Head-column field-amplified sample stacking in capillary electrophoresis for the determination of cimetidine, famotidine, nizatidine, and ranitidine-HCl in plasma.

In this study, low concentrations of histamine2-receptor (H2-)antagonists were effected across a water plug, with separation taking place in a binary buffer comprising ethylene glycol and NaH2PO4 (pH 5.0), and detection at 214 nm. Liquid-liquid extraction with ethyl acetate- isopropanol is shown to provide extracts that are sufficiently clean. The calibration curves were linear over a concentration range of 0.1-2.00 microg/mL cimetidine, 0.2-5.0 microg/mL ranitidine-HCl, 0.3-5.0 microg/mL nizatidine, and 0.1-3.0 microg/mL famotidine. Mean recoveries were > 82%, while the intra- and interday relative standard deviations (RSDs) and relative errors (REs) were all < 13%. The method is sensitive with a detection limit of 3 ng/mL cimetidine, 30 ng/mL ranitidine HCl, 50 ng/mL nizatidine and 10 ng/mL famotidine (S/N = 3, electric-driven injection 90 s). This newly developed capillary electrophoresis (CE) method was applied for the determination of analytes extracted from plasma taken from a volunteer dosing a cimetidine, ranitidine, and nizatidine tablet simultaneously. These three H2-antagonists can be detected in real samples by this method, excluding the low dosing of famotidine tablet.     

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.     

Fast determination of Z-ligustilide in plasma by gas chromatography/mass spectrometry following headspace single-drop microextraction

Angelica sinensis (danggui in Chinese) is a common traditional Chinese medicine (TCM), and its essential oil has been used for the treatment of many diseases such as hepatic fibrosis. Z-Ligustilide has been found to be an important active component in the TCM essential oil. In this work, for the first time, headspace single-drop microextraction (HS-SDME) followed by gas chromatography-mass spectrometry (GC-MS) was developed for the determination of Z-ligustilide in rabbit plasma after oral administration of essential oil of danggui. The extraction parameters of solvent selection, solvent volume, sample temperature, extraction time, stirring rate, and ion strength were systemically optimized. Furthermore, the method linearity, detection limit, and precision were also investigated. It was shown that the proposed method provided good linearity (0.02-20 microg/mL, R2 = 0.997), low detection limit (10 ng/mL), and good precision (RSD value less than 9%). Finally, HS-SDME followed by GC/MS was used for fast determination of Z-ligustilide in rabbit plasma at different time intervals after oral administration of danggui essential oil. The experimental results suggest that HS-SDME followed by GC/MS is a simple, sensitive, and low-cost method for the determination of Z-ligustilide in plasma, and a low-cost approach to pharmacokinetics studies of active components in TCMs.     

Optical nitrite sensor based on chemical modification of a polymer film

A new, low-cost nitrite sensor was developed by immobilizing a direct indicator dye in an optical sensing film for food and environmental monitoring. This sensor was fabricated by binding gallocyanine to a cellulose acetate film that had previously been subjected to an exhaustive base hydrolysis. The membrane has good durability (>6 months) and a short response time (<7 s). Nitrite can be determined for the range 0.008-1.50 microg/ml with 3delta detection limits of 1 ng/ml. The method is easy to perform and uses acetylcellulose as a carrier. The reagents used for activating the cellulose support are inexpensive, non-toxic and widely available.     

Preparation of two-dimensional molybdenum disulfide for NO2 detection at room temperature

In this work, the two-dimensional MoS₂ film was prepared by sulfuring the molybdenum atomic layer on SiO₂/Si substrate. The reaction temperature, heating rate, holding time and carrier gas flow rate were investigated comprehensively. The quality of MoS₂ film was characterized by optical microscopy, atomic force microscopy, Raman and photoluminescence spectroscopy. The characterization results showed that the optimum synthesis parameters were heating rate of 25 °C/min, reaction temperature of 750 °C, holding time of 30 min and carrier gas velocity of 100 sccm. The MoS₂ gas sensor was fabricated and its gas sensing performance was tested. The test results indicated that the sensor had a good response to both reducing gas (NH₃) and oxidizing gas (NO₂) at room temperature. The sensitivity to 100 ppm of NO₂ was 31.3%, and the response/recovery times were 4 s and 5 s, respectively. In addition, the limit of detection could be as low as 1 ppm. This work helps us to develop low power and integrable room temperature NO₂ sensors.