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.
Figure
A gas sensor for propionaldehyde was fabricated based on the cataluminescence (CTL) emission generated by the catalytic oxidation of propionaldehyde on a nanosized ZrO2 surface. The sensor showed highly sensitivity and good selectivity to propionaldehyde with a response time of less than 3 s and a recovery time of under 20 s 相似文献
Estrogen plays a crucial role in various stages of human development and is present in the human body at trace level; therefore, an efficient strategy for the quantitative analysis of trace estrogens is required. However, this analysis is complicated by the presence of extremely complex biological matrices. To address this challenge, a novel method based on monolithic column solid-phase microextraction and ultra-high-performance liquid chromatography-tandem mass spectrometry was developed for the sensitivity analysis of six estrogens: β-estradiol, α-estradiol, 17α-ethynylestradiol, estrone, diethylstilbestrol, and hexestrol, in human urine and serum samples. The method exhibits a low limit of detection (8.6–37 ng L?1), with wide linear ranges (0.10–25 μg L?1) for each analyte and remarkable correlation coefficients (R2?=?0.9953–0.9995). The developed method was successfully used to detect estrogens in urine and serum samples. The six analytes were satisfactorily recovered between 76.2 and 107% with relative standard deviations ranging from 2.5 to 8.3% (n?=?3). The results demonstrated that the developed method, based on a poly(methacrylic acid/3-acrylamidophenylboronic acid-co-ethylene glycol dimethacrylate) monolithic column, is an effective enrichment approach toward the analysis of trace estrogens in human urine and serum samples.
A novel aptamer‐modified magnetic mesoporous carbon was prepared to develop a specific and sensitive magnetic solid‐phase extraction method through combination with ultra‐high performance liquid chromatography‐tandem mass spectrometry for the analysis chloramphenicol in complex samples. More specifically, the chloramphenicol aptamer‐modified Mg/Al layered double hydroxide magnetic mesoporous carbon was employed as a novel magnetic solid‐phase extraction sorbent for analyte enrichment and sample clean‐up. The extraction solvent, extraction time, desorption solvent, and desorption time were investigated. It was found that the mesoporous structure and aptamer‐based affinity interactions resulted in acceptable selective recognition and a good chemical stability toward trace amounts of chloramphenicol. Upon combination with the ultra‐high performance liquid chromatography‐tandem mass spectrometry technique, a specific and sensitive recognition method was developed with a low limit of detection (0.94 pmol/L, S/N = 3) for chloramphenicol analysis. The developed method was successfully employed for the determination of chloramphenicol in complex serum, milk powders, fish and chicken samples, giving recoveries of 87.0‐107% with relative standard deviations of 3.1‐9.7%. 相似文献
The fabrication of efficient fluorescent probes that possess an excellent sensitivity and selectivity for uric acid is highly desirable and challenging. In this study, composites of silver nanoparticles (AgNPs) wrapped with nitrogen-doped carbon quantum dots (N-CQDs) were synthesised utilising N-CQDs as the reducing and stabilising agents in a single reaction with AgNO3. The morphology and structure, absorption properties, functional groups, and fluorescence properties were characterised by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, fluorescence spectroscopy, and X-ray diffraction spectroscopy. In addition, we developed a novel method based on AgNPs/N-CQDs for the detection of uric acid using the enzymatic reaction of uric acid oxidase. The fluorescence enhancement of the AgNPs/N-CQDs composite was linear (R2 = 0.9971) in the range of 2.0–60 μmol/L, and gave a detection limit of 0.53 μmol/L. Trace uric acid was successfully determined in real serum samples from the serum of 10 healthy candidates and 10 gout patients, and the results were consistent with those recorded by Qianxinan Prefecture People’s Hospital. These results indicate that the developed AgNP/N-CQD system can provide a universal platform for detecting the multispecies ratio fluorescence of H2O2 generation in other biological systems. 相似文献