Article of the Year 2021
Point-of-Care Diagnoses and Assays Based on Lateral Flow TestRead the full article
International Journal of Analytical Chemistry publishes research reporting new experimental results and chemical methods, especially in relation to important analytes, difficult matrices, and topical samples.
Chief Editor, Professor Charles L. Wilkins, is a Distinguished Professor of Chemistry and Biochemistry at the University of Arkansas, USA. His research focuses on the development of novel analytical chemistry instrumentation and analysis paradigms.
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Relationship between the UPLC Fingerprints of Citrus reticulata “Chachi” Leaves and Their Antioxidant Activities
Citrus reticulata “Chachi” (CRC) leaves contain abundant flavonoids, indicating that they possess good nutritional/pharmacological research and development potential. This study aims to explore chemical antioxidant quality markers based on the spectrum-effect relationship and quality control strategy of CRC leaves. The ultrahigh performance liquid chromatography (UPLC) system was used to establish chromatographic fingerprints of Citrus reticulata “Chachi” leaves. Simultaneously, they were evaluated by using similarity analysis (SA), hierarchical cluster analysis (HCA), and principal component analysis (PCA). Afterwards, the DPPH assay was adopted to study the antioxidant effects. The spectrum-effect relationship between UPLC fingerprints and DPPH radical-scavenging activities was studied with grey relational analysis (GRA). Analysis results indicated that there were twenty-one common peaks of fourteen batches of CRC leaves which were from different regions of Guangdong province, and their similarities ranged from 0.648 to 0.997. HCA results showed that fourteen batches of samples of CRC leaves could be divided into six classes at Euclidean distance of 5. The results from GRA showed that tangeretin and hesperidin were the main flavonoids responsible for the antioxidant activity in CRC leaves. In conclusion, this research established a chromatographic analysis method suitable for CRC leaves and demonstrated that chromatographic fingerprints analysis combined with the antioxidant activity could be used to evaluate the material basis of CRC leaves and may provide a reference to establish a quality standard.
Synthesis of Chitosan Microparticles Encapsulating Bacterial Cell-Free Supernatants and Indole Acetic Acid, and Their Effects on Germination and Seedling Growth in Tomato (Solanum lycopersicum)
Encapsulation of biostimulant metabolites has gained popularity as it increases their shelf life and improves their absorption, being considered a good alternative for the manufacture of products that stimulate plant growth and fruit production. Cell-free supernatants (CFS) were obtained from nine indole-3-acetic acid (IAA) producing bacterial strains. Stenotrophomonas maltophilia (PT53T) produced the highest concentration of IAA (15.88 μg/mL) after 48 h of incubation. CFS from this strain, as well as an IAA standard were separately encapsulated in chitosan microparticles (CS-MP) using the ionic gelation method. The CS-MP were analyzed by Fourier transform infrared spectroscopy (FTIR), showing absorption bands at 1641, 1547, and 1218 cm−1, associated with the vibrations of the carbonyl C=O, the N-H amine, and the bond between chitosan (CHI) and sodium tripolyphosphate (TPP). The effects of unencapsulated CFS, encapsulated CFS (EN-CFS), and encapsulated IAA standard (EN-IAA) on germination and growth of seven-day-old tomato (Solanum lycopersicum) seedlings were studied. Results showed that both EN-CFS and EN-IAA significantly () increased seed germination rates by 77.5 and 80.8%, respectively. Both CFS and EN-IAA produced the greatest increase in aerial part length and fresh weight with respect to the treatment-free test. Therefore, it was concluded that the application of EN-CFS or EN-IAA could be a good option to improve the germination and growth of tomato seedlings.
Application of Cement-Based Carbon Fiber Material in Construction of Building Durability
In order to solve the problem of drying shrinkage of cement-based carbon fiber materials in the early stage of hardening, the author proposes the application of cement-based carbon fiber materials in the construction of building durability. The author uses a self-designed fast ring test method to test and study the drying shrinkage performance of cement-based carbon fiber materials in the early stage of hardening. The results showed that the addition of MP-I and MP-II fibers, which can significantly reduce shrinkage cracking in plastic concrete, has little effect on preventing the shrinkage and cracking of concrete in the early stage of hardening. Mixed with a certain amount of steel fiber, carbon fiber, MH-I, and MPH-I hardened anticrack fiber, all have a better effect on preventing early water loss and drying shrinkage of hardening. The MH-I and MPH-I hardening anticracking fibers have an economical and feasible dosage, and the early water loss shrinkage and crack reduction rates of concrete hardening are 71.2% and 79.0%, respectively. MH-I fibers have no anticracking effect in the plastic stage and are only suitable for shrinkage and crack prevention of concrete in the early stage of hardening, while MPH-I hardened anticrack fibers have a 100% crack-reducing effect in the plastic stage, it is an engineering fiber material that can simultaneously prevent the plasticity and early hardening of concrete from shrinkage and cracking. The application of MPH-I hardened anticrack fiber is of great significance to improve the quality of structural engineering.
Application of 3D Printing Technology and Porous Nano-Ceramic Decorative Sheet in Interior Landscape Design
In order to solve the problems that the traditional ceramic method is difficult to form porous ceramics with complex structures, the mold production cycle is long, and the cost is high, the authors propose the application of 3D printing technology and porous nano-ceramic decorative sheet in interior landscape design. Based on the use of photocuring molding technology to make high-precision regular resin molds, optimize the low-viscosity, high-solid content alumina ceramic slurry required by the gel injection molding process and form alumina ceramic blanks by means of a vacuum pressure process, so as to realize the net shape of complex structural porous ceramic parts. In view of the filling problem of ceramic slurry in complex structure in the process, the effects of slurry pH value, dispersant dosage, and vacuum pressurization process on ceramic molding were studied, and parameters such as porosity and compressive strength of the green body were tested. Experimental results show the following. Under the conditions of pH value of 9, mass fraction of dispersant of 0.4%, and vacuum pressure of 90 min, alumina ceramics with a volume fraction of 52% can be prepared, the porosity is 51.5%, and the compressive strength is 40.1 MPa. The ceramic material prepared by this process has complete structure and smooth surface and can be used as a process for preparing porous ceramic parts with complex structure.
The Research Progress in the Application of Ceramic Nanofibers in Antibacterial Textile Materials
In order to investigate the application effect of ceramic nanofibers in antibacterial textile materials and improve the comprehensive use efficiency of antibacterial textile materials, ceramic nanofibers were introduced firstly and their fabrication methods and specific functions were discussed. Then, the antibacterial textile materials were introduced and their main uses and contributions were discussed. Finally, the application of ceramic nanofibers in antibacterial textile materials was investigated based on CiteSpace software. The results showed that the research on ceramic nanofibers had increased rapidly since 2000. Also, the number of the foreign literature retrieval was about 9,200 at most and 6,300 at least. The number of Chinese literature was about 6,000 at most and 1,000 at least. It can be seen that the current research of ceramic nanofibers is quite mature. But the quantity of the research on ceramic nanofibers in the application of antibacterial materials is relatively small. In the foreign literature retrieval, the number of the literature was about 1,300 at most and about 220 at least. In the Chinese literature retrieval, the number of the literature was about 600 at most and about 30 at least. It can be seen that the current domestic research on the application of ceramic nanofibers in antibacterial textile materials is not mature, but the foreign research is relatively good. The research not only provides a reference for the further research of ceramic nanofibers but also contributes to the improvement of antibacterial textile materials.
Development of Green UV-Vis Method for Direct Determination of Total Sugars in the Aqueous Extract of Teff (Eragrostis tef (Zuccagni) Trotter) Grains and Other Cereals
There is no ultraviolet visible (UV-Vis) spectrophotometric method for the direct determination of total sugars in the aqueous extract of teff grain samples. Therefore, the objective of this study was to develop a green UV-Vis spectrophotometric method to determine total sugars in the aqueous extract of white teff, brown teff, white rice, and red wheat grain samples. The calibration curve was established in the range of 20.11–7,907 mg/L using sucrose as a standard with R2 = 0.9996. The limit of detection and limit of quantification were 4.4 and 14.6 mg/L, respectively. The relative standard deviation (6.9%) of the method for the sucrose standard was within the acceptable range indicating that the method is precise. The amount of total sugars determined in the white teff (5.48–9.44% (w/w), brown teff (6.17–10.32% (w/w)), white rice (3.19% (w/w)), and red wheat (9.22% (w/w)) grain samples was comparable with other reported cereal grains. Furthermore, the accuracy of the developed analytical method was also evaluated by spiking the known amount of the sucrose standard solution to the white teff, brown teff, white rice, and red wheat sample extracts, and percentage recoveries found were in the acceptable range (85 ± 2 − 105 ± 4%) with an average recovery of 93%, confirming that the new green method is quantitatively reproducible. Hence, a fast, simple, inexpensive, widely used, selective, sensitive, precise, and accurate green UV-Vis method was developed and validated for the direct determination of total sugars in the aqueous extract of teff, white rice, and red wheat grain samples.