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Nguyen Thanh-Nho,Thai Huynh-Thuc,Le-Thi Anh-Dao,Do Minh-Huy,Le-Thi Huynh-Mai,Le Quang-Huy,Nguyen-Thi Kim-Sinh,Nguyen Cong-Hau 한국분석과학회 2023 분석과학 Vol.36 No.5
Aluminium (Al) is one of the major elements in rocks and its concentration can be varied, depending on different rock types as well as sources. The present study aimed to propose an analytical method based on the UV-Vis as a cheap, simple, and common instrument equipped in most laboratories for Al quantification in rocks after the microwave assisted acid digestion. The aluminone and 8-hydroxyquinoline were investigated for the colorimetric assay. The results show that the 8-hydroxyquinoline reagent was more favorable in terms of the minimized affects of the potential interferences present in the digested solutions, i.e., Fe3+, Si4+ and F–. The calibration curve was constructed from 0.10 mg/L to 3.00 mg/L with the goodness of linearity (R2 = 0.9996). The limits of detection and quantification (LOD and LOQ) were estimated, i.e., 0.029 mg/L and 0.087 mg/L, respectively. The 8-hydroxyquinoline was applied to real rock samples, demonstrating favorable precision (RSD = 0.34 %-1.8 %) and no remarkable differences were found compared to the inductively coupled plasma-mass spectrometry (ICP-MS) as a reference measurement approach.
The Effect of Social Capital on Social Entrepreneurial Intention among Vietnamese Students
HA, Ngoc Thang,DOAN, Xuan Hau,VU, Trong Nghia,NGUYEN, Thi Phuong Linh,PHAN, Thanh Hoa,DUONG, Cong Doanh Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8
This study develops the model to estimate the links between social capital, social entrepreneurial self-efficacy, perceived desirability and social entrepreneurial intention. Besides exploring the direct impacts of social capital, social entrepreneurial self-efficacy, and perceived desirability on social entrepreneurial intention, this study also focus on discovering the mediating roles of perceived desirability and social entrepreneurial self-efficacy on this relationship. Throughout adopting measures from some previous studies, the authors design the questionnaires and distribute to students in Vietnam. The study presents some demographic information of 289 students, who are studying at university and colleges in Vietnam. Then, the validity and reliability of scales are assessed using the value of Cronbach's alpha, Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). In addition, by utilizing the structural modeling structure (SEM), the authors show that social capital plays the important role in shaping social entrepreneurial self-efficacy, perceived desirability, and social entrepreneurial intention. Interestingly, besides the direct effects on social entrepreneurial intention, perceived desirability and social entrepreneurial self-efficacy also mediate the correlation between social capital and social entrepreneurial intention. Also, with the interesting findings of the study, the authors propose several recommendations for policy-makers, educators and academics to promote the social entrepreneurship and innovation among Vietnamese students.
Le-Thi Anh-Dao,Do Minh-Huy,Nguyen-Ho Thien-Trang,Nguyen Cong-Hau 한국분석과학회 2024 분석과학 Vol.37 No.2
The appropriate intake of fluoride (F–) is beneficial to human health; however, the over-consumption can result in various potentially harmful effects. This study compared different colorimetric reagents, i.e., aluminium-xylenol orange (Al-XO), zirconium-xylenol orange (Zr-XO), and zirconium-alizarin red S (Zr-ARS), for fluoride measurements by the UV-Vis, in terms of reaction mechanisms, method sensitivity, and interferences from aluminium and ferric ions. The colorimetric procedures were optimized, and the analytical methods were evaluated. The goodness of linearity (R2 > 0.998) was obtained for all three assays within the concentration range of 1.0-20.0 mg/L fluoride in deionized water, in which the method sensitivity followed the descending order of Zr-XO > Al-XO > Zr-ARS. The Zr-XO was applied for determining the fluoride in different tea extracts in water (90 °C and 60-minute-brewing) and black tea demonstrated the highest fluoride content (3.0-3.6 mg/L). The effects of brewing time and temperature on the release of fluoride in the tea extracts were also investigated, indicating these are critical factors for the fluoride extraction. This study highlighted the application potentials of the UV-Vis measurement as a simple, convenient, and cheap analytical approach and discussed different colorimetric reagents used for fluoride determination in tea extracts in the context that the UV-Vis spectrophotometers are commonly equipped in most laboratories.
Le-Thi Anh-Dao,Do Minh-Huy,Vo Hong-Phong,Nguyen Cong-Hau 한국분석과학회 2023 분석과학 Vol.36 No.5
In the present study, an analytical method was proposed for detecting trifluralin in aquatic products at trace concentrations. The method employed QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) as the sample preparation and measurement, respectively. The effect of the aqueous phase volume used in the QuEChERS was demonstrated, and the ratio of 10:10 (mL) between water and acetonitrile phase was used for 5 g of sample. Besides, dSPE using C18 and primary-secondary amine (PSA) was applied to remove the potential interferences from the food matrices, indicating no remarkable analyte loss. The linear range was built up from 0.50 μg L–1 to 3.0 μg L–1 (R2 = 0.9993). Other criteria, i.e., repeatability (RSDr = 0.86-1.96 %), reproducibility (RSDR = 1.09-2.01 %), and recovery (over 90 %), were in accordance with Appendix F of AOAC (2016) for method performance. Although no trifluralin was detected for the commercial samples (fish, shrimp, and breaded shrimp), the spiked samples performed favorable recoveries and precision.