Saijing Zheng

Preparation of phenyl group-functionalized magnetic mesoporous silica microspheres for fast extraction and analysis of acetaldehyde in mainstream cigarette smoke by gas chromatography–mass spectrometry

Acetaldehyde is regarded as a toxic mainstream cigarette smoke constituent, and measurement of acetaldehyde in complex real samples is difficult owing to its high volatility and reactivity. In this work, phenyl group-functionalized magnetic mesoporous microspheres were developed as the solid-phase extraction sorbents for enrichment and analysis of acetaldehyde in mainstream cigarette smoke. The functional magnetic microspheres were first synthesized through a facile one-pot co-condensation approach. The prepared nanomaterials possessed abundant silanol groups in the exterior surface and numerous phenyl groups in the interior pore-walls, as well as a large surface area (273.5m(2)/g), strong superparamagnetism and uniform mesopores (3.3 nm). Acetaldehyde in mainstream cigarette smoke was collected in water and derivatizated with O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine. The formed acetaldehyde oximes were extracted and enriched by the prepared adsorbents via π-π interactions and subsequently analyzed using GC-MS. Extraction conditions such as amounts of sorbents, eluting solvent, adsorption and desorption time were investigated and optimized to achieve the best efficiency. Method validations including linearity, recovery, repeatability, and limit of detection were also studied. It was found that the suggested methodology provided low detection limit of 0.04 mg/mL, good recovery of 88-92%, intra-day and inter-day RSD values of 4.5% and 10.1%, and linear range of 0.25-4 mg/mL (R(2)=0.999). The results indicated that the proposed method based on phenyl-functionalized magnetic mesoporous microspheres was rapid, efficient and convenient for the enrichment and analysis of acetaldehyde in tobacco.

Development of magnetic graphene as an adsorbent and matrix for selective enrichment and detection of crotonaldehyde in saliva by MALDI-TOF-MS

Crotonaldehyde has long been regarded as an important environmental pollutant from cigarette smoke to human health. To have an efficient and high-throughput screening of crotonaldehyde in saliva samples, it is essential to develop an analytical method considering both enrichment and measurement processes. In this study, we proposed a novel method based on matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for the analysis of crotonaldehyde in saliva. Magnetic graphene was synthesized via a facile hydrothermal process, and then applied as an adsorbent and a matrix for MALDI-TOF-MS. Crotonaldehyde in saliva was derived by 2,4-dinitrophenylhydrazine first followed by a magnetic solid-phase extraction process and high-throughput MALDI-TOF-MS detection. Due to its large surface area, strong interaction force and excellent inherent properties, magnetic graphene showed a satisfactory ionization and enrichment performance for the enrichment and ionization of crotonaldehyde by MALDI-TOF-MS. The crotonaldehyde derivatives could be sensitively detected from saliva samples even at a low concentrations. The results indicated that the proposed method was simple, rapid, sensitive and efficient for the analysis of crotonaldehyde in saliva and other biological samples.

Surface properties of solid materials measured by modified inverse gas chromatography.

A novel modified inverse gas chromatography (IGC) method has been developed to investigate the surface properties of solid materials. On the modified IGC system, the every adjusted retention time of miscellaneous probe molecules can be rapidly calculated within only one sample injection through wisely induction a capillary column and two detectors, i.e., flame ionization detector (FID) and thermal conductivity detector (TCD). In the system, the relative dead time can be acquired from FID detector while the retention time can be obtained from TCD detector simultaneously. The significant advantage of our design is that, experimental time is greatly saved compared to the traditional IGC. In addition, the new system is capable of distinguishing variety surface properties of porous materials. Two types of active carbon samples were tested, and the results showed that their thermodynamic parameters were quite different, indicating that the samples have opposite acidic/basic properties. The use of IGC would be an effective tool to evaluate the physiochemical data of solid materials.

Development of microwave-assisted headspace solid-phase microextraction followed by gas chromatography-mass spectrometry for the analysis of phenol in a cigarette pad

Phenol is a mainstream cigarette smoke constituent and has been classified as a main toxic component directly related to environmental and health issues. Analysis of phenol in mainstream cigarette smoke is of great importance. In this work, microwave-assisted headspace solid-phase microextraction (HS-SPME) was developed for the fast analysis of phenol in a cigarette pad. Analyte in a Cambridge cigarette pad, activated by a short period of microwave irradiation, was headspace extracted by SPME and analyzed by GC-MS. Extraction conditions such as microwave irradiation time, SPME fiber coating, adsorption time and desorption time were investigated and optimized to achieve the best effect. The method was validated through the investigation of linearity, detection limit, recovery and precision. The linearity was in a wide range of 0.005–1 μg mL−1 with a correlation coefficient R2 = 0.999. The limit of detection was as low as 0.5 ng mL−1, and acceptable recovery and RSD values of 86.5% and 11.5% were achieved. The proposed method was successfully applied to the analysis of phenol in cigarette pad samples. The experimental results have demonstrated that microwave-assisted HS-SPME followed by GC-MS was a rapid, efficient and convenient method for the determination of phenol in tobacco products.