|
1. Full name: Hoang Thai Long
2. Sex: Male
3. Date of birth: 08/11/1960
4. Place of birth: Hue City
5. Admission decision number: 212/SĐH, Dated 12/08/2004 of Vietnam National University, Hanoi.
6. Changes in academic process: Decision for extension number 1220/SĐH, dated 19/10/2007 of the Director of College of Science, Vietnam National University, Hanoi.
7. Official thesis title: Study on the determination of trace arsenic in aquatic environment by stripping voltammetry
8. Major: Analytical Chemistry
9. Code: 62 44 29 01
10. Supervisors:
- Main supervisor: Assoc. Dr. Hoang Tho Tin
- Secondary supervisor: Prof. Dr. Tu Vong Nghi
11. Summary of the new findings of the thesis:
- A new gold film electrode (AuFE ex-in) was developed, by using a simple fabrication that can be applied to poor equipped laboratories in Vietnam. This new electrode has overcome the limitation of the conventional gold film electrode on reproducibility when used for arsenic determination..
- AsIII can be analyzed by using DP-ASV/AuFE ex-in with a good reproducibility (RSD = 3.5%, n = 20), good sensitivity (109.1 nA/ppb), low detection limit (0.4 ppb), and wide linear range (2 – 80 ppb). In comparison with the conventional AuFE (AuFE ex-situ), DP-ASV using AuFE ex-in gave better reproducibility, detection limit and linear range.
- For the first time, Na2S2O4 was used to reduce AsV to AsIII for total inorganic As determination by DP-ASV. AsV is calculated by difference from total inorganic As and AsIII. .
- Interference of ZnII, CuII, SO42-, and NO3- ions become significant only at very high concentrations compared to theirs concentration in aquatic environment. FeII and FeIII only slightly affect when their concentrations are higher than AsIII concentration 200 times. At a concentrations less than 1 M, Cl- ion increases Ip of arsenic, but decreases it at higher concentrations. AsIII does not interfere with AsV reduction and analysis.
- An analysis procedure has been successfully established using DP-ASV/AuFE ex-in for the determination of AsIII and AsV in aquatic environment. Reliability of this procedure was verified by CRM determination test. 21 water samples were also analyzed by using two different determination methods (DP-ASV/AuFE ex-in and HG-AAS). The obtained results were not significantly different.
12. Practical applicability, if any: Proposed method for arsenic determination by using DP-ASSV/AuFE ex-in situ can be applied to determine arsenic in natural and wastewater samples. This method may effectively fulfill the needs of investigating and assessing arsenic pollution of water sources in Vietnam with a low determination cost in comparison with other spectrometry methods.
13. Futher research directions, if any:
- Study and develop digestion method to determine arsenic in other environment samples, such as biosamples, material samples, by proposed determination method;
- Study on new electrode materials to develops electrochemical methods for arsenic determination;
- Study on the change in the micromorphology of AuFE surface in arsenic the ASV determination of arsenic.
14. Thesis-related publications:
1. Hoang Thai Long, Nguyen Thi Minh Trang, Nguyen Van Hop, Tu Vong Nghi, Hoang Tho Tin (2005). “Study on the development of activated gold film electrode
for trace AsIII determination by anodic stripping voltammetry”. Proceedings of the Second National Conference on Analytical Sciences, Hanoi, pp. 255-259.
2. Hoang Thai Long, Hoang Nhat Hung, Nguyen Van Hop, Tu Vong Nghi, Hoang Tho Tin (2008). “Determination of As(III) by cathodic stripping voltammetry in the presence of sodium diethyldithiocarbamate” Journal of Analytical Sciences, Vol. 13 (2), pp. 40-44.
3. Hoang Thai Long, Bui Hai Dang Son, Nguyen Van Hop, Hoang Tho Tin, Tu Vong Nghi (2008). “Development of Gold Film Electrode for Anodic Stripping Voltammetric Determination of Trace Arsenic(III) in Natural Water”. Proceedings of the International Scientific Conference on “Chemistry for Development and Integration”, Hanoi, pp. 558-567.
4. Hoang Thai Long, Tran Thi Hanh, Nguyen Van Hop, Hoang Tho Tin, Tu Vong Nghi, Yuta Yasaka (2008). “A new preparation of gold film electrode for anodic stripping voltammetric determination of AsIII”. Proceedings of The 8th General Seminar of the Core University Program on “Environmental Science & Technology for the Earth”, Osaka, pp. 368-375.
5. Nguyen Van Hop, Hoang Thai Long, Nguyen Hai Phong, Nguyen Thi Ngoc Anh (2009). “Development Of Mercury-free Metal Film Electrode For Stripping Voltammetric Measurement Of Trace Heavy Metals”. Proceedings of The International Conference on Analytical Sciences and Biotechnology, Hanoi, pp. 93-102.
6. Hoang Thai Long, Duong Van Hau, Nguyen Van Hop, Hoang Tho Tin, Tu Vong Nghi (2009). “Gold film electrode preparation and activation methods for the determination of arsenic by differential pulse anodic stripping voltammetry”. Journal of Chemistry, Vol. 47 (5A), pp. 285-290.
7. Hoang Trong Sy, Hoang Thai Long, Le Thi Anh Phuong (2010). “Determination of As(III) by square wave anodic stripping voltammetry method using gold film electrode ex situ”. Journal of Analytical Sciences, Vol. 15 (1), pp. 36-41.
|
