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1 THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY NGO QUI TRUNG COMPARISON OF SPE VALLME AND VALLME WITH INCREASED SAMPLE VOLUME FOR SENSITIVITY ENHANCEMENT IN DETERMINATION OF STRONTIUM[.]
THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY NGO QUI TRUNG COMPARISON OF SPE-VALLME AND VALLME WITH INCREASED SAMPLE VOLUME FOR SENSITIVITY ENHANCEMENT IN DETERMINATION OF STRONTIUM BY ION CHROMATOGRAPHY BACHELOR THESIS Study Mode : Full-Time Major : Environmental Science and Management Faculty : International Programs Office Batch : 2013 – 2017 Thai Nguyen, 20/07/2017 DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University Of Agriculture And Forestry Degree Program: Bachelor of Environmental Science and Management Student name: Ngo Qui Trung Student ID: DTN 1253060212 Comparison of solid phase extraction combined with vortex-assisted liquid-liquid micro-extraction and vortex- Thesis Title: assisted liquid-liquid micro-extraction with increased sample volume for sensitivity enhancement in the determination of strontium by ion chromatography Assoc Prof Dr Wu, Chien-Hou - National Tsing Hua Supervisor (s): University,Taiwan Assoc Prof Dr Nguyen The Hung - Thai Nguyen University of Agriculture and Forestry, Vietnam Abstract: Strontium compound that is considered a danger to human health If it absorb to much in the body, it will make some disease such as: lung cancer or bone cancer Many methods was found by difference scientists but the sensitivity quite low Therefore, in this research, we compared solid phase extraction and large sample volume (50 mL) combined with vortex-assisted liquid–liquid micro-extraction to test the sensitivity enhancement in the determination of strontium by ion chromatography According to VALLME, dispersion of micro-volumes of a low density extraction organic solvent into the water sample is achieved by using for the first time vortex mixing Strontium from the organic phase was stripped with nitric acid back to aqueous solution and determined by ion chromatography The optimum microextraction conditions were as follows: 50 mL aqueous samples with mL 50 mM TPB; 400 μL of 1-octanol as the extraction phase with 10 mM DtBuCH18C6 followed by sequential vortex 20s and manual shaking 10s The strontium-rich organic solvent was recovered by centrifugation at 3200 rcf for The calibration curve showed good linearity over the range between 0.01 and 0.1 mg L-1 with detector sensitivity was 0.7635 and a correlation coefficient higher than 0.9992 while the LOD was 8.74 µg L-1 Moreover, when we combined vortex-assisted liquid–liquid micro-extraction with solid phase extraction at the same linearity range, the detector sensitivity was 1.0671 and the correlation coefficient R2 was 0.9861 Therefore, SPE-VALLME methodology more effective than other methods (with highest detector sensitivity) when we increased sample volume Key-words: Strontium (Sr), solid-phase extraction (SPE), ion chromatography, vortex-assisted liquid–liquid microextraction (VALLME) Number of pages: 53 Date of submission: 20th September, 2017 Supervisor’s signature ACKNOWLEDGEMENT Firstly, I would like to express the deepest appreciation to teachers in faculty of International Training and Development as well as teachers in Thai Nguyen University of Agriculture and Forestry, who have dedicated teaching to me the valuable knowledge during study time in university and gave me a chance to my thesis oversea It is with immense gratitude that I acknowledge the support and help of Biomedical Engineering & Environmental Science Department, National Tsing Hua University for accepting me to working in this wonderful place Foremost, I would like to express my sincere gratitude and deep regards to my supervisor: Assoc Prof Dr Wu, Chien-Hou of National Tsing Hua University (Taiwan), who guidance, encouragement, suggestion and very constructive criticism have contributed immensely to the evolution of my ideas during the project Without his guidance, I may not have this thesis My special thanks go to Mr.Bill (Wang Chin Yi) Ph.D student-second supervisor - who offered me a warm welcome and provided the information and data necessary for my implementation process and helped me finish this thesis I sincerely thanks to Assoc Prof Dr Nguyen The Hung for his advices, assistance, sharing experiences before and after I went to Taiwan, helping me to understand and complete proposal and thesis My sincere thanks also go to all my classmates – K45 AEP for helping me finish the study Special thanks to Lam, Tar Mivongsack, members in Chien’s laboratory who hearty help me a lot of when I work in there and all the people who helped me when I stayed in Hsinchu - Taiwan Finally, I would like to thank my family, for their love and supporting me throughout my life In the process of implementing the project, I know that my thesis report got many mistakes so this report is inevitable shortcomings So, I would like to receive the attention and feedback from teachers and friends to this thesis is more complete Hsinchu, April 2017 Student Ngo Qui Trung TABLE OF CONTENT LIST OF FIGURES LIST OF TABLES LIST OF ABBREVIATIONS 10 PART I INTRODUCTION 11 1.1 Research rationale 11 1.2 Objectives of this research 12 1.3 Research questions and hypothesis 13 1.4 Limitation of this research 13 PART II LITERATURE REVIEW 14 2.1 The characteristics and health effects of strontium(Sr) 14 2.1.1 Characteristics of strontium 14 2.1.2 Applications 16 2.1.3 Origins of strontium in the environment 16 2.1.4 Health effects of strontium 16 2.1.5 Effects of strontium on the environment 18 2.2 Methods to determine strontium in the environmental sample 19 2.2.1 Solid-phase extraction (SPE) 19 2.2.2 Vortex-assisted liquid-liquid microextraction (VALLME) 23 2.2.3 Combination two methods: solid-phase extraction and vortex-assisted liquid-liquid microextraction (SPE-VALLME) 26 2.3 Crown ether 28 2.4 NaTPB (Sodium tetraphenylboron) 31 PART III.METHOD 32 3.1 Material 32 3.1.1 Chemical materials 32 3.1.2 Instrumentation 32 3.2 Method 34 3.2.1 Determine the optimum concentration 34 3.2.2 Solid-phase extraction (SPE) 36 3.2.3 Vortex-assisted liquid-liquid microextraction (VALLME) 37 4.1 Analysis 38 PART IV: RESULTS 39 PART V: DISCUSSION AND CONCLUSION 47 4.2 Discussion 47 4.3 Conclusion 48 REFERENCES 49 LIST OF FIGURES Figure 2.1 Solid phase extraction steps 22 Figure 2.2 Structures of common crown ether: 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 and diaza-18-crown-6 29 Figure 3.1 Ion chromatography system diagram 34 Figure 4.1 Recovery strontium of 100ml sample volume 3M HNO3 and chromatography graph of samples 39 Figure 4.2 Recovery strontium of 100ml sample volume 8M HNO3 and chromatography graph of samples 40 Figure 4.3 Calibration curve of concentration Sr (II) at low volume sample (2ml)415 Figure 4.4 Comparison 1-octanol recovery between solution sample with crown ether, TPB and without crown ether,TPB 37 Figure 4.5 Effect of volume of extraction solvent on the extraction efficiency of strontium Extraction condition: volume 50ml, Sr (II) concentration 50µg/L, 3ml TPB 38 Figure 4.6 Calibration curve of concentration Sr (II) at high volume sample (50ml) 39 Figure 4.7 Comparison solid phase extraction combined with vortex-assisted liquidliquid microextraction and vortex-assisted liquid-liquid microextraction at low and high volume 40 LIST OF TABLES Table 2.1 Physical and chemical properties of strontium (A.crawford 1790) 15 Table 2.2 Properties of 4’,4”(5”)-di-tert-butyldicyclohexano 18-crown-6 30 Table 2.3 Properties of sodium tetraphenylboron (NaTPB) 31 Table 4.1 Comparison recoveries 1-octanol with and without crown ether and TPB 36 LIST OF ABBREVIATIONS SPE Solid phase extraction Vortex-assisted liquid–liquid micro- VALLME extraction Solid phase extraction combined with SPE-VALLME vortex-assisted liquid–liquid microextraction PPB Part per billion PPM Part per million Sr Strontium IC Ion chromatography DIW Deionised water High Performance Liquid HPLC Chromatography Gas chromatography–mass GC-MS spectrometry 10