Tài liệu Mechanism of vortex assisted liquid liquid microextraction of strontium in water sample

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY CHU NGUYEN THE STUDY MECHANISM OF VORTEX-ASSISTED LIQUID-LIQUID MICROEXTRACTION OF STRONTIUM IN WATER SAMPLE BACHELOR THESIS Study mode : Full-time Major : Environmental Science and Management Faculty : Advanced Education Program Office Batch : 2014 - 2018 Thai Nguyen 24/9/2018 DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of Environmental Science and Management Student name Chu Nguyen Student ID DTN1453150016 Thesis Title Supervisors Mechanism of vortex-assisted liquid-liquid microextraction of Strontium in water sample - Prof. Wu ,Chien-Hou - Prof. Nguyen The Hung Supervisor’s Signature Abstract: A vortex-assisted liquid–liquid microextraction method was applied in many years ago, however the first time it was developed for the chromatographic determination of strontium (alkaline-earth) in aqueous samples in 2017. In the extraction , strontium was in aqua phase with the presence of tetraphenylborate as the counter anion, while organic phase (1- octanol was chosen) was complexed with 4′,4″(5″)-di-(tert-butylcyclohexano)-18-crown-6 (7:1 respectively ). Strontium from the organic phase was stripped with nitric acid back to aqueous solution and determined by ion chromatography. By changing the concentration of 4′,4″(5″)-di-(tert-butylcyclohexano)-18-crown6 and tetraphenylborate, with standard conditions as vortex for 10s; centrifugation at 6000 rpm for 4 min; stripping by 0.1 M nitric acid and lightproof condition, the result is that with [TPB]=0,003 M and [DtBuCH18C6]= 0,01 M, the extraction of Sr is i optimum with Recovery rate= 79% ,and distribution coefficient logD =1,22. Key words Strontium, tetra phenyl borate, ion chromatography, strontium, vortex-assisted liquid–liquid micro-extraction Number of pages 50 Date of Submission: 24/09/2018 ii ACKNOWLEDGEMENT To have completed this thesis, in addition to the ongoing efforts of myself, I would like to thank for teachers in Advanced Education Program Office 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 do 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. Furthermore, express my sincere deepest gratitude to Prof. Wu Chien Hou, from Biomedical Engineering & Environmental Science Department, National Tsing Hua University,who provided physical conditions in laboratory, documents and allowed me to trigger my experiments by myself, and Prof. Nguyen The Hung from Thai Nguyen University of Agriculture and Forestry, who guided and created favorable conditions for me during the implementation of this thesis. Next, i would like spend special thanks to Ms. Pham Thi Hai Van - MSc student who suggested, directly guided to do research my thesis, Ms Yang ziruo who teach me tips, principle and working-skills in the laboratory and usage of all devices used in my experiments. Besides, they provided the information and data necessary for my implementation process and helped me finish this thesis. Finally, I would like to sincerely thank my family, all of my friends who always beside me all the time, giving spiritual help for me complete the tasks assigned during learning and doing this thesis experiment. iii In the process of implementing the project, my thesis might have inevitable shortcomings. Therefore, I appreciate very much if I may receive the attention and feedback from teachers and friends for this thesis is more completion Sincerely, Chu Nguyen iv TABLE OF CONTENT DOCUMENTATION PAGE WITH ABSTRACT ................................................................ i ACKNOWLEDGEMENT .................................................................................................... iii TABLE OF CONTENT ........................................................................................................ v LIST OF TABLES .............................................................................................................. vii LIST OF FIGURES ............................................................................................................ viii LIST OF ABBREVIATIONS .............................................................................................. ix PART I. INTRODUCTION .................................................................................................. 1 1.1. Research rationale .......................................................................................................... 1 1.2. Objectives of the research .............................................................................................. 3 1.3. Research questions and hypothesis ................................................................................ 3 1.4. Limitations of research ................................................................................................... 3 PART II. LITERATURE REVIEW ...................................................................................... 4 2.1. Strontium ........................................................................................................................ 4 2.1.1 The properties of strontium .......................................................................................... 4 2.1.2. The interaction of strontium with environment ........................................................... 6 2.1.3 Effects of Strontium to human‘s health ....................................................................... 7 2.2 Method Review ............................................................................................................. 11 2.2.1 Vortex-assisted liquid–liquid micro-extraction .......................................................... 11 2.2.1. a Vortex-assisted liquid–liquid micro-extraction concept and mechanism .............. 11 2.2.1.b The factors affect to the vortex-assisted liquid-liquid microextraction. ................. 13 2.2.1.c Advantages of VALLME and applications ............................................................. 14 2.2.2 Crown ether- DtBuCH18C6 ....................................................................................... 15 2.2.3 Sodium tetraphenylborate ........................................................................................... 18 2.2.4.Ion Chromatography ................................................................................................... 20 2.2.4.a Ion Chromatography mechanism. ............................................................................ 20 2.2.4.b Ion chromatography system. ................................................................................... 21 PART III. METHODS ......................................................................................................... 26 3.1. Material ......................................................................................................................... 26 v 3.1.1 Chemical materials .................................................................................................... 26 3.1.2 Instrumentation ........................................................................................................... 26 3.2 Methods ......................................................................................................................... 27 3.2.1 Micro-extraction procedure ........................................................................................ 27 3.2.2 Analysis ...................................................................................................................... 28 PART IV. RESULTS .......................................................................................................... 29 4.1 The effect of DtBuCH18C6 and TPB concentration to result of Strontium extraction.29 4.2 Calibration Curve .......................................................................................................... 33 PART V. DISCUSSION AND CONCLUSION ................................................................. 34 5.1. DISCUSSION............................................................................................................... 34 5.2 CONCLUSION. ............................................................................................................ 34 REFERENCE ..................................................................................................................... 35 vi LIST OF TABLES Table 2.1. The properties of strontium ................................................................................ 4 Table 2.2. Properties of 4’,4’’(5’’)-di-tert-butyldicyclohexano 18-crown-6 (DtBuCH18C6) (12)( en.wikipedia.org) ........................................................................... 18 Table 2.3. Properties of sodium tetraphenylboron (NaTPB)(13 ) ( en.wikipedia.org) ..... 19 Table 2.4. Function of parts in an IC system.................................................................... 23 vii LIST OF FIGURES Figure.2.1. Applications of VALLME procedure in real samples (C. Bosch Ojeda ,F. Sánchez Rojas, 2014) ....................................................................... 15 Figure 2.2. Ion Chromatography System Configuration ................................................... 22 Figure 3.1. A vortex-assisted liquid–liquid microextraction process ............................... 27 Figure 4.1. The variance of Peak Area of Sr2+ when DtBuCH18C6 concentration is changed ................................................................................................... 29 Figure 4.2. The variance of Peak Area of Sr2+ when TPB concentration is changed ....... 29 Figure 4.4 .Effect of TPB concentration on the distribution coefficient of Sr .................. 31 Figure 4.5. Effect of DtBuCH18C6 concentration on the distribution coefficient of Sr .. 31 Figure 4.6. Extraction of Sr as a function of DtBuCH18C6 concentration ...................... 32 Figure 4.7. Calibration Curve ............................................................................................ 33 viii LIST OF ABBREVIATIONS Aqueous Phase AP Distribution Coefficient D Aqueous Sample DP 4’,4’’(5’’)-Di-Tert-butyldicyclohexano 18-crown-6 DtBuCH18C6 Ion Chromatography IC Liquid–Liquid Microextraction LLE Strontium Sr Vortex-Assisted Liquid–Liquid Microextraction VALLME ix PART I. INTRODUCTION 1.1. Research rationale Commonly, natural strontium compounds coexist with other alkali and alkaline-earth compounds, such as sodium, calcium, magnesium, and barium compounds, which make the separation of strontium more complex. Fuming nitric acid has been used previously to separate strontium from large quantities of alkali, alkaline-earth, and other elements effectively (Ying et al., 2015). However, the Vortex-assisted liquid–liquid microextraction is discovered as an efficient method to extract Strontium in water sample which is complexed 4′,4″(5″)-di-(tert-butylcyclohexano)-18-crown-6 in the presence of tetraphenylborate as the counter anion (Chin-Yi et al., 2017). Moreover, Agency for Toxic Substances and Disease Registry reported (2000), study the mechanism of this method and optimize the efficiency of the extraction of Strontium, also it‘s applications in the future, the my research was implemented . On the other hand, strontium is an element which affects seriously to human and environment also. Firstly, human exposure to strontium is primarily by the oral route (via fruits, vegetables, and drinking water,) although inhalation exposures are also possible. No toxic effects of stable strontium have been reported for the exposure levels normally encountered in the environment. Strontium is not readily absorbed through intact skin, but is absorbed through abraded skin and through puncture wounds. The biological effects of strontium are related to its chemical similarity to calcium, with both elements being found in Group 2 of the periodic table and forming divalent cations (Agency for Toxic Substances and Disease Registry, 2000). However, since strontium is not the same size as calcium, it does not substitute precisely for calcium in biological processes. At different stages of the life cycle, organisms vary in their ability to discriminate between strontium 1 and calcium, which may cause age-related differences in gastrointestinal absorption, and therefore in health effects. Because of its similarity to calcium, strontium accumulates to a high degree in bone, and, in high concentrations, may seriously interfere with the normal process of bone development. The young are particularly vulnerable because a lack of discrimination between calcium and strontium occurs during a dynamic period of bone formation and growth. For this reason, body burdens of strontium will be higher in children than in adults, and the health effects associated with high exposure levels would be more severe (Atlanta, 2004). Radioactive strontium isotopes incorporate into bone and irradiate the bone cells, the hemopoietic bone marrow, and potentially, the soft tissues surrounding bone, especially in the skull. The external dose from strontium radionuclides emitting beta radiation outside the body is normally of little health concern unless the radioactive material contacts the skin (Agency for Toxic Substances and Disease Registry, 2000). Skin contact can allow the beta radiation to pass through the epidermis to live dermal tissue where it becomes a major contributor to a radio strontium-generated radiation dose to the skin. At very high doses, the beta radiation can cause such adverse effects as erythema, ulceration, or even tissue necrosis (Atlanta, 2004). Once radioactive strontium is internalized, it is absorbed, distributed, and excreted in the same manner as stable strontium; the chemical similarity of strontium to calcium results in deposition of radioactive strontium in bone. The internal radiation dose from strontium is actually a measure of the amount of energy that the beta emissions deposit in tissue (Agency for Toxic Substances and Disease Registry, 2000). The short-range beta radiation produces a localized dose, generally to bone and the soft tissues adjacent to bone; hemopoietic bone marrow is the most biologically significant target of radioactive 2 strontium emissions (Fischer, M., & Kampen, W. U., 2012). Molecular damage results from the direct ionization of atoms that are encountered by beta radiation and by interactions of resulting free radicals with nearby atoms. Tissue damage results when the molecular damage is extensive and exceeds the capacity of natural repair mechanisms (Atlanta, 2004). 1.2. Objectives of the research By comparing the result of strontium extractions which is implement with changing of 18C6 and TPB concentration, the specific objectives of this study are: - The optimal condition of microextraction of strontium - The mechanism of 4′,4″(5″)-di-(tert-butylcyclohexano)-18-crown-6 1.3. Research questions and hypothesis 1. which concentration of 4′,4″(5″)-di-(tert-butylcyclohexano)-18-crown-6 and TPB have the highest sensitivity micro-extraction of Strontium? 2. How effective is the VALLME with ratio 1:7 for Organic phase : Aqueous phase ? 1.4. Limitations of research However, the thesis training time was too short, the device has had errors for 2 months and, this research project is still completed on the time by myself with the supports. 3 PART II. LITERATURE REVIEW 2.1. Strontium 2.1.1 The properties of strontium Table 2.1 The properties of strontium Properties Value Melting point 777oC, 1050 K Boiling point 1380oC, 1653 K Atomic weight 87.62 g.mol-1 Density 20oC 2.6g/cm3 Atomic number Ionic radius Isotopes 38 0.113nm (+2) 14 Electronic shell [Kr] 5s2 Energy of first ionization 549.2 kJ.mol-1 Energy of second ionization 1064 mol-1 (Source: Lenntech, 1998) Strontium is a natural and commonly occurring element. Strontium can exist in two oxidation states: 0 and +2. Under normal environmental conditions, only the +2 oxidation state is stable enough to be important. Pure strontium is a hard, white-colored metal, but this form is not found in the environment. Rather, strontium is usually found in nature in the form of minerals. Strontium can form a variety of compounds. Strontium compounds do not have any particular smell (Agency for Toxic Substances and Disease Registry, 2018). There are two types of strontium compounds, those that dissolve in water and those that do not. Natural strontium is not radioactive and exists in four stable types (or isotopes), each of which can be written as 84Sr, 86Sr, 87Sr, and 88Sr, and read as strontium eighty-four, strontium eighty-six, etc. All four isotopes behave the same 4 chemically, so any combination of the four would have the same chemical effect on your body (Atlanta, 2004). Rocks, soil, dust, coal, oil, surface and underground water, air, plants, and animals all contain varying amounts of strontium. Typical concentrations in most materials are a few parts per million (ppm). Strontium ore is found in nature as the minerals celestite (SrSO4) and strontianite (SrCO3). After the strontium is extracted from strontium ore, it is concentrated into strontium carbonate or other chemical forms by a series of chemical processes (Agency for Toxic Substances and Disease Registry, 2018). Strontium compounds, such as strontium carbonate, are used in making ceramics and glass products, pyrotechnics, paint pigments, fluorescent lights, medicines, and other products. Strontium can also exist as radioactive isotopes. 90Sr, or strontium ninety, is the most hazardous of the radioactive isotopes of the chemical element strontium. 90Sr is formed in nuclear reactors or during the explosion of nuclear weapons. Each radioactive element, including strontium, constantly gives off radiation, and this process changes it into an isotope of another element or a different isotope of the same element (Agency for Toxic Substances and Disease Registry, 2004). This process is called radioactive decay. 90Sr gives off beta particles (sometimes referred to as beta radiation) and turns into yttrium ninety (90Y); 90Y is also radioactive and gives off radiation to form zirconium ninety (90Zr), which is a stable isotope. The radioactive half-life is the time that it takes for half of a radioactive strontium isotope to give off its radiation and change into a different element. 90Sr has a half-life of 29 years (Atlanta, 2004). 90Sr has limited use and is considered a waste product. The radioactive isotope 89Sr is used as a cancer therapeutic to alleviate bone pain. 85Sr has also been used in medical applications. 5 Quantities of radioactive strontium, as well as other radioactive elements, are measured in units of mass (grams) or radioactivity (curies or becquerels). Both the curie (Ci) and the becquerel (Bq) tell us how much a radioactive material decays every second. The becquerel is a new international unit known as the SI unit, and the curie is an older unit; both are used currently (Agency for Toxic Substances and Disease Registry, n.d). A becquerel is the amount of radioactive material in which 1 atom transforms every second. One curie is the amount of radioactive material in which 37 billion atoms transform every second; this is approximately the radioactivity of 1 gram of radium. 2.1.2. The interaction of strontium with environment Stable and radioactive strontium compounds in the air are present as dust. Emissions from burning coal and oil increase stable strontium levels in air. The average amount of strontium that has been measured in air from different parts of the United States is 20 nano-grams per cubic meter (a nano-gram is a trillion times smaller than a gram). Most of the strontium in air is in the form of stable strontium. Very small dust particles of stable and radioactive strontium in the air fall out of the air onto surface water, plant surfaces, and soil either by themselves or when rain or snow falls. These particles of strontium eventually end up back in the soil or in the bottoms of lakes, rivers, and ponds, where they stay and mix with stable and radioactive strontium that is already there (Atlanta, 2004). In water, most forms of stable and radioactive strontium are dissolved. Stable strontium that is dissolved in water comes from strontium in rocks and soil that water runs over and through. Only a very small part of the strontium found in water is from the settling of strontium dust out of the air. Some strontium is suspended in water. Typically, the amount of strontium that has been measured in drinking water in different parts of the United States by the Enviromental Protection and Agency is less than 1 milligram for 6 every liter of water (1 mg/L). 90Sr in water comes primarily from the settling of 90Sr dust out of the air. Some 90Sr is suspended in water. In general, the amount of 90Sr that has been measured in drinking water in different parts of the United States by EPA is less than one-tenth of a picocurie for every liter of water (0.1 pCi/L or 0.004 Bq/L). Strontium is found naturally in soil in amounts that vary over a wide range, but the typical concentration is 0.2 milligrams per kilogram (kg) of soil (or 0.2 mg/kg). The disposal of coal ash, incinerator ash, and industrial wastes may increase the concentration of strontium in soil. Generally, the amount of 90Sr in soil is very small and is only a fraction of the total concentration of strontium in soil. Higher concentrations of 90Sr in soil may be found near hazardous waste sites, radioactive waste sites, and Department of Energy facilities located around the United States (Agency for Toxic Substances and Disease Registry, 2004). A major portion of stable and radioactive strontium in soil dissolves in water, so it is likely to move deeper into the ground and enter groundwater. However, strontium compounds may stay in the soil for years without moving downward into groundwater. In the environment, chemical reactions can change the water-soluble stable and radioactive strontium compounds into insoluble forms. In some cases, waterinsoluble strontium compounds can change to soluble forms. For more information about the transport properties of stable and radioactive strontium in the environment. 2.1.3 Effects of Strontium to human‘s health To protect the public from the harmful effects of toxic chemicals and to find ways to treat people who have been harmed, scientists use many tests. One way to see if a chemical will hurt people is to learn how the chemical is absorbed, used, and released by the body. In the case of a radioactive chemical, it is also important to gather information concerning the radiation dose and dose rate to the body (Agency for Toxic Substances and Disease Registry, 2004). For some chemicals, animal testing may be necessary. Animal 7 testing may also be used to identify health effects such as cancer or birth defects. Without laboratory animals, scientists would lose a basic method to get information needed to make wise decisions to protect public health. Scientists have the responsibility to treat research animals with care and compassion. Laws today protect the welfare of research animals, and scientists must comply with strict animal care guidelines (Agency for Toxic Substances and Disease Registry, 2018). There are no harmful effects of stable strontium in humans at the levels typically found in the environment. The only chemical form of stable strontium that is very harmful by inhalation is strontium chromate, but this is because of toxic chromium and not strontium itself. Problems with bone growth may occur in children eating or drinking unusually high levels of strontium, especially if the diet is low in calcium and protein (Hassan, 2014). Ordinary strontium salts are not harmful when inhaled or placed on the skin. Animal studies showed that eating or drinking very large amounts of stable strontium can be lethal, but the public is not likely to encounter such high levels of strontium. In these unusually high amounts, so much strontium was taken into bone instead of calcium that growing bones were weakened. Strontium had more severe effects on bone growth in young animals than in adults (Agency for Toxic Substances and Disease Registry, 2018). It is not known whether stable strontium affects reproduction in people. The effect of stable strontium on reproduction in animals is not known. The Department of Health and Human Services has determined that strontium chromate is expected to be a carcinogen, but this is because of chromium. There is no information that any other form of stable strontium causes cancer in humans or animals (Agency for Toxic Substances and Disease Registry, 2004). 8 The harmful effects of radioactive strontium are caused by the high energy effects of radiation. Since radioactive strontium is taken up into bone, bone itself and the soft tissues nearby may be damaged by radiation released over time. Because bone marrow is the essential source of blood cells, blood cell counts may be reduced if the dose is too high. This has been seen in humans who received injections of radioactive strontium (89Sr) to destroy cancer tissue that had spread to the bone marrow (Radiation damage and protection levels, 2013). Lowered blood cell counts were also seen in animals that breathed or swallowed radioactive strontium. Numerous problems occur when the number of blood cells is too low. A loss of red blood cells, anemia, prevents the body from getting sufficient oxygen, resulting in tiredness. A loss of platelets may prevent the blood from clotting properly, and may result in abnormal bleeding, especially in the intestines. A loss in white blood cells harms the body’s ability to fight infectious disease. Radiation damage may also occur from exposure to the skin. Medically, radioactive strontium probes have been used intentionally to destroy unwanted tissue on the surface of the eye or skin. The eye tissues sometimes become inflamed or abnormally thin after a long time. Thinning of the lower layer of the skin (dermis) has also been reported in animal studies as a delayed effect (Agency for Toxic Substances and Disease Registry, 2004). It is not known whether exposure to radioactive strontium would affect human reproduction. Harmful effects on animal reproduction occurred at doses that were more than a million times higher than typical exposure levels for the general population. Radioactive strontium may cause cancer as a result of damage to the genetic material (DNA) in cells. An increase in leukemia over time was reported in individuals in one foreign population who swallowed relatively large amounts of 90Sr (and other radioactive 9 materials) in river water contaminated by a nuclear weapons plant. Cancers of the bone, nose, and lung (in the case of a breathing exposure), and leukemia were reported in animal studies (Agency for Toxic Substances and Disease Registry, 2004). In addition, skin and bone cancer were reported in animals that received radiation at high doses to the skin. The International Agency for Research on Cancer (IARC) has determined that radioactive strontium is carcinogenic to humans, because it is deposited inside the body and emits beta radiation. The EPA has determined that radioactive strontium is a human carcinogen. Specially, children are exposed to stable strontium in the same manner as adults: usually in small amounts in drinking water and food. Young children who have more hand-to-mouth activity or who eat soil may accidentally eat more strontium (Alexander et al., 1973). Infants and children with active bone growth absorb more strontium from the gut than adults. Excess stable strontium causes problems with growing bone. For this reason, children are more susceptible to the effects of stable strontium than adults who have mature bone. Children who eat or drink unusually high levels of stable strontium may have problems with bone growth, but only if the diet is low in calcium and protein (Alexander et al., 1973). Children who drink milk, especially milk fortified with vitamin D, are not likely to have bone problems from exposure to excess stable strontium. The amount of stable strontium that is usually taken in from food or water or by breathing is too low to cause bone problems in children. No developmental studies in humans or animals examined the effect on the fetus when the mother takes in excess strontium. However, no problems are expected with fetal bone growth because only small amounts of strontium are transferred from the mother across the placenta to the fetus. Evidence suggests that stable strontium can be transferred from the mother to nursing infants 10