CHAPTER IBACKGROUND A. Background We already know that the atom consists of a nucleus of an atom and the electrons circulating around it. Ordinary chemical reactions (such as combustion reaction and salting), only involves a change in the atomic shell, especially electrons in the outer shell, while the atomic nucleus unchanged. Reactions relating to changes in the nucleus called a nuclear reaction or a nuclear reaction (nucleus = core). No nuclear reactions that occur spontaneously or artificial. Spontaneous nuclear reaction occurs in the nucleus of an unstable atom. Substances containing an unstable nucleus is called a radioactive substance. The nuclear reaction can not spontaneously occur in a stable core and the core is not stable. Energy nuclear reactions accompanied by changes in the form of radiation and heat. Various types of nuclear reactions accompanied by the release of heat is very powerful, larger and ordinary chemical reactions. It turns out, many elements are naturally radioactive. All isotopes of atomic numbers above 83 are radioactive. Element atomic number 83 or less have a stable isotope of technetium and promesium exception. Radioactive isotopes are called radioactive isotopes or radioisotopes, isotopes that are not radiaktif called stable isotopes. Today, radioisotopes may also be made of stable isotopes. So in addition to natural radioisotopes are also no artificial radioisotopes. The use of radioisotope techniques today has expanded in various fields, such as chemistry, medicine, animal husbandry and agriculture, steel industry, the food industry, the field of hydrology and sedimentology field. These applications are intended for human welfare in various fields. Radioisotopes are commonly used in various fields of human needs such as health, agriculture, hydrology and industry, especially in chemical midwife who comes to the analysis of a sample, tracer techniques and the like are very helpful in the study. In general, there is no radioisotope in nature because most of its half-life is relatively short. Radioisotopes created within a nuclear reactor that has a density (flux) high neutron by reaction between certain atomic nuclei with neutrons. In addition, radioisotopes may also be produced using the accelerator through the reaction between certain atomic nuclei with a particle, such as alpha, neutrons, protons or other particles. Therefore, the existence of this paper is to determine the usefulness of radioisotopes in chemistry both in terms of application and specifications. B. Problem 1. What are the application of radioisotopes in chemistry? 2. How does the use of radioisotopes in chemistry? CHAPTER II DISCUSSION A. Definition of Radioisotopes Radioisotopes can occur naturally or intentionally (synthesis) created by humans in the research reactor. Radioisotopes are commonly used in various fields of human needs such as health, agriculture, hydrology and industry, in general, does not exist in nature, as most paronya relatively short lifespan. Therefore made radioisotopes synthesis. Radioisotope production with the activation process (synthesis) carried out by shooting at stable isotopes with neutrons in the reactor core. This process is commonly called a neutron irradiation, while the irradiated material is called the target or targets. The process created within a nuclear reactor that has a density (flux) high neutron by reaction between certain atomic nuclei with neutrons. Neutrons are fired will be entered into the target atomic nucleus so that the number of neutrons in the nucleus of the target increases. These events can lead to instability of the nuclei thus transformed into a radioactive nature. In addition, radioisotopes may also be produced using the accelerator through the reaction between certain atomic nuclei with a particle, such as alpha, neutrons, protons or other particles. An element that is identical from the chemical properties of the material may vary slightly in weight. These characteristics can be explained that the atoms in the same element can have different numbers of neutrons in the nucleus. Differences in these forms known as isotopes. Examples of carbon element that has three natural isotopes is C-12, C-13, C-14. The third of these isotopes have the same chemical properties as the same number of protons but a different number of neutrons, this affects the physical properties of each atom. If the number of neutrons equal to or more than the number of protons, the nucleus so stable and so-called stable isotopes. When the number of neutrons less than the number of protons, the nucleus is unstable nuclei will release energy in the form of radiation. Isotope with an unstable nucleus is known as radioisotopes. Radioactive substances is any substance that emits ionizing radiation with a specific activity greater than 70 kBq / kg or 2 nCi / g (seventy kilobecquerel per kilogram or two nanocurie per gram). Figures 70 kBq / kg (2 nCi / g) is a reference to a substance can be called a common radioactive substances on its established by the International Atomic Energy Agency (International Atomic Energy Agency). However, there are some substances that despite having a lower specific activity than that limit can be regarded as radioactive substances as defined may not limit the same for all substances given the nature of each of these substances is different. Here are the benefits and dangers of radioactive substances in everyday life. B. Useful of radioactive chemistry 1. Tracer technique Tracer technique can be used to study the mechanisms of various chemical reactions. For example in the esterification reaction. With oxygen-18 can be followed by a reaction between carboxylic acid and alcohol. From the analysis of mass spectroscopy, esterification reaction that occurs can be written as follows. (isotope oxygen-18 are colored). Results of this analysis showed that water molecules do not contain oxygen-18. If you want to know the water O atoms derived from the carboxylic acid or alcohol, then I know is to use O-18 radioisotope. If the O-18 is used as an OH group of carboxylic acids turned out to be found in water. Whereas if the O-18 is used as the alcohol turns out that we find on the ester. In addition, the use of radioisotopes in the field of chemistry is to study the dynamic equilibrium, suppose the equilibrium between solid PbI2 with ions in a saturated solution. We want to know whether, after equilibrium is reached, the reaction is still in progress or not. The trick is to make a saturated solution PbI2 in glass A and glass B. In A glass used PbI2 containing radioactive I-131 was on the glass and used PbI2 not contain radioactive. Furthermore, some of the solvent from the glass A (excluding sediment) was transferred to the glass B. After a while deposition on glass and analyzed, turned out to contain radioactive PbI2. So it can be concluded that after the equilibrium is achieved PbI2 formation reaction was continued and at the same time took place PbI2 dissolution reaction. a). The use of tracer principle Tracer method (tracer) has been used in virtually every field of science and technologies such as medicine, biology, chemistry, agriculture, physiology, nutrition, physics, instrumentation, pharmaceutical, toxicology, biotechnology and so on. Applications in this method is to perform tracing of the object under study or called Tracee. Tracee may be a component of substan substan or as radicals, molecules or atoms. The ideal tracer must have physical, chemical, or biological weapons together with Tracee studied. The nature of these characteristics makes it possible to detect in the system where Trace it. The principle of tracer production involves a replacement (substitution) of one or more atomatom of specific positions in the molecule with an isotope trace in the atom. Stable isotopes and radioactive isotopes can be used as a tracer. The difference lies in the masses of the isotopes of different numbers of neutrons, thus not affect its chemical properties. Nature can not distinguish between stable isotopes and radioactive isotopes in the same material, they can take part in chemical reactions in the materials or the same element. The use of tracer labeling requires an assumption that there will be no difference between the molecules or atoms are labeled with molecules that are not labeled and will trace the position or movement of the molecules that are not labeled. As has been explained that the various isotopes in an element having physical and chemical properties are almost identical, just have different masses. This difference makes an isotopdapat distinguish between isotopes from one another. The use of several isotopes for observing a process of evaporation or rootuptake in plants, can be observed using elements with low molecular weight. The radiation emitted by the radioisotope during decay can ionize the atoms around it. A number of compounds will emit light when exposed to radiation, the intensity of the emitted light depends on the radiation exposure. Light intensity is measured with a scintillation counter and a Geiger counter or ionization chambers. b. Measurement tracer Radioisotope tracer can be detected based on the nature of decay, which is a type of radiation emitted and energy as well as time paronya. When a small amount of radioisotope used and the length of time it takes half a statistically significant measurement technique dibutuhkanuntuk as stable isotopes. On the use radioisotoptersebut is necessary to note these things: 1) The nature of the radioactive Radioisotope tracer is a radioactive source was in the sample. Thus the final enumeration must be corrected for decay background (Background) agarmendapatkan absolute values. The radiation emitted in the decay of a single nucleus can ionize the atoms around it but rarely have an influence on the bottom line. c. Measurement is based on the stimulation of the response to stimuli To detect a stable isotope or radioisotope with low activity, then measurements required by stimulation of a typical response (isotopic), can pass through; • Application of the electrical circuit to ionize the sample, thus atomatom and molecules can be distinguished by a mass ratio charge (m / z values), so that the tracer can be determined based on the mass of the core. As an example; tracer contained in the sample can be determined by measuring the intensity of the current according to the tracer ion using a detector such as Faraday cups, secondary electron multipliers and so on. • Induction of nuclear reactions by shooting a bullet with the samples using a particular type and energy. Thus tracer distinguished based on the emission of radioactive reaction products. 2. Use of Isotopes in the Field of Chemical Analysis The use of isotopes in the analysis used to determine trace elements in the sample. Analysis with radioisotopes or called radiometric can be done in two ways, as follows: 1) Isotope Dilution Analysis. Isotope dilution analysis to determine the levels of a substance is done by adding a radioactive substance known activity of its kind and has been diluted into a substance that will be assayed. The compounds used have properties identical to the compound to be analyzed. On isotope dilution analysis, into a solution to be analyzed is added a solution containing a known amount of radioactive species and an unknown substance. The substance then separated, and radioactivity is determined. Isotope dilution analysis process in general is: Analysis mixture of compounds based on the type of footage, with a component that has been known to kind of activity; Quantitative determination of compounds in complex mixtures can be implemented by adding the compound marked with the liveliness of the type and number of known accurately; for this purpose should be used compounds labeled with properties identical to the compound to be determined. When the compound to be determined can be separated in a pure state, but it is not necessary to obtain the results of the quantitative separation, the levels of the compounds in question can be determined by comparing the activity types before and after separation. a) First, a known amount of an isotope is added to the sample. For example, to determine the amount of I in the sample solution of KI, I131 labeled compounds added AgNO3 and HNO3. (Standard solution or a solution with activity before dilution) For the sample solution, a number of compounds marked I131ditambahkan into KI solution that is going to react with AgNO3 stabil.Penambahan KI in the sample, causing AgI precipitate, whereas in the standard AgI precipitate is formed as AgNO3 reacts with I131 which are radioactive. HNO3 serve to acidic conditions, perfecting AgI precipitate formation, and removes the matrix - matrix interrupt the reaction. Then the precipitate is filtered AgI, counted and weighed. From the experiments showed that the first mass in the sample amounted to 182.894 mg while the KI concentration was 956.4 ppm. Analyzed solution and standard solution was added a solution containing a radioactive species. The substance then separated and determined activity. Concentration of the solution being analyzed is determined by comparison with standard solutions. 2) Neutron Activation Analysis (NAA). Analysis Activation Neutron, or abbreviated with the APN (= NAA, Neutron Activation Analysis) is an analytical technique un sur which is based on the emission of radiation y when nuclides an element of catch and! Or react with thermal neutrons (neutrons with kinetic energy less than 0 , 1 key). This technique is one of the utilization of nuclear techniques in the fields of chemical analysis, in addition to other analytical techniques such as radioisotope dilution analysis and radioimmunoassay. Rad APN method can be used for qualitative and quantitative analysis. This technique can also be used for the simultaneous analysis of multiple elements at once without being distracted by the chemical form of each element and the similarities or differences in the chemical properties of elements are analyzed. This is due to the interaction of the elements with neutrons produce nuclides sensitivity characteristics which are difficult or can not be achieved by means of another analysis. Even the technique of APN otherwise be able to detect and determine the level of trace element content and ultra-trace for no less than 75 kinds of elements. APN technique was first introduced by Hevesy and Levi in 1936 while doing research suggests that exposure to neutrons in materials containing rare earth elements keradoaktivan very high yield. Oari observation of the onset keradioaktivan. Neutron activation analysis can be used to determine the trace elements in the sample being a solid. Eg for determining heavy metals (Cd) in the samples of sea belt. Samples irradiated with neutrons in the reactor to become radioactive. One of the emitted radiation is gamma rays. Further samples of minced with a gamma spectrometer to determine the activity of the elements to be determined. Basic Principles state budget If a nuclide element / atom is irradiated with the thermal neutron core neutron capture reaction occurs that produces the species, which is very unstable and are at the level of excitation energies corresponding to the neutron binding energy with the target nuclides. In order very short period, between the species suffered deeksitasi energy level is accompanied by emission of γ radiation called γ radiation - prompt (prompt-y) and core transformation has occurred generate radioactive nuclides (= radionuclide). lradiasi with thermal neutrons followed by radiation emission of y-prompt terse but declared a nuclear reaction A (n, γ) A * A is the target nuclide (= nuclide irradiated) and * A is a radionuclide produced. Compared with the target nuclides, radionuclides nuclear reaction products (n, γ) does not change the number of protons, but the number of neutrons increased by one. Thus the product radionuclides are radioactive isotopes of the elements of the target. Furthermore, A * decay and emit γ radiation or a particle or particles or particles ~ + ~ - or a combination of ke'empatnya. Oalam relation to APN, γ radiation accompanying the decay is called γ radiation -tunda (delayed- γ). Nuclides decay product is new, it may still radioactive but which might also be stable nuclides. Grouping Techniques APN grouped by 2 different categories. The first is based on the type of radiation y were measured, and the second based on the presence or absence of component separation treatment footage before the measurement process. APN grouping based on the type of radiation γ. Based on the type of γ radiation being measured, categorized APN techniques in utilizing APN- prompt γ γ radiation -prompt, and APN- γ γ -tunda using radiation from radionuclides decay product activation [3,4]. Oi in APN- γ- prompt, detection and measurement carried out during the activation process. This technique is usually used neutron beams extracted through a door beam of neutrons in the reactor so that the neutron flux that is used is much lower than the neutron flux in the reactor core, which is about one millionth of the neutron flux in the reactor core. Because the technique APN- γ -prompt more done for the analysis of elements that have a neutron absorption cross section is high, eg B, Cd, Sm, and Od, element in the activation produce radionuclides with very short half-life or a radionuclide that decays emit low energy γ radiation. In APN- γ -tunda, detection and measurement carried out after the completion of activation in the peri ode radionuclides decay time product activation. The second technique is more of a public option that APN designation is usually meant as APN- γ delay. APN grouping based on whether there is a separation process APN grouping in this category there are two kinds, namely APN instrumental (APNI) and APN radiochemical (APNR). Oi in separation techniques APNI not equal at all. After irradiation (activation), with or without a cooling stage after irradiation, footage can be directly measured. Keradioaktivan that is not mutually interfere with the implementation of the detection and measurement of each. Adults 1 m APN analysis equipment generally been equipped with automatic data processing system and computed. APNI technique is becoming the choice of many people because it is much simpler and easier to do so in connection with this category generally referred to APN is APNI. To facilitate the separation of radiochemical techniques APNR, after the cooling process after the irradiation, the footage analyte (either in a form absorbed on filter paper or in the form of other preparation) was dissolved again in a suitable solvent and then added a carrier prior to the separation process. Chemical species added carrier must comply with the elements to be separated and are intended to contain un sur which is intended to be the amount which enables the separation chemistry. Furthermore, radiochemical separation process can be done with appropriate techniques, such as precipitation. chromatography, extraction, electrochemical and so on. Each [Raksi separated and left. When required to be analyzed, measured and specified further in the geometric sarna with standard footage. b) Some Important Aspects In APN Capability and sensitivity analysis As one element analysis techniques, APN not only has high sensitivity, but also can be applied to the analysis of approximately 70% of the elements that have been known so far [1]. Footage analyte can be derived from a variety of materials, such as foodstuffs, biological materials, environmental materials, industrial materials, pharmaceutical materials and so on. c) Advantages and limitations of APN as an analytical technique other elemental analysis techniques Excellence: a). Is a multi-element analysis techniques simultaneously for qualitative and quantitative analysis, and does not depend on the level of oxidation or chemical and physical form of the element being analyzed. b). The detection sensitivity is so high that only the required amount of euplikan (mass weight or volume) of the Minor. c) In many ways a non-destructive analytical techniques, it is not necessary for the separation process analysis. d). If the means of irradiation and measurement instruments have been available, the analysis can be done with a procedure that is easy, fast and simple. e). No analysis could be disrupted by chemical contaminants in the environment. f). Can be applied to about 70% of this type of element on the Periodic Map euplikan in a wide variety of materials. g). Oari one irradiation process can be repeated measurements adjusted with the span of half-element analysis. Limitations: a) Requires neutron source facility (nuclear reactor or neutron generator) that can not always be shared by all laboratory chemical analysis. b). Legality and require special permits with respect to aspects of safety and / or radiation protection. e). Does not provide information on the chemical form or degree of oxidation of the analyte elements. d). It can not be done for the analysis of certain elements such as elements cross section of neutrons reaction is very low (for this type of analysis such as activating proton activation analysis system using a cyclotron can be a complement to the APN). d) Some kind of interference in the APN Some rnacarn disorders irnplernentasi dalarn APN can rnengurangi accuracy and effectiveness analysis, among others: • Spectral Disorders. Spectral interference occurs when two rnacarn radionuclide results rnenghasilkan activation energy y adjacent. It Inl rnenyebabkan chopped overlap that can rnenghasilkan error information obtained. If this situation can not be overcome by the use of high resolution detector, rnaka required re-measurement after a certain time interval after a short half-life time of radionuclides that may be considered rneluruh exhausted. • Disturbance second order additive. Second-order interference occurs when the additive element in dalarn rnatrik analyte rnenghasilkan radionuclides rneluruh rnenjadi stable isotopes are equal to the elements analyzed so happens pertarnbahan nuclear reactions produce readionuklida analyzed. For example, in the analysis of phosphorus by reaction 31p (n, y) 32P, there will be disruption of the Si in the matrix, because Si will undergo nuclear reaction 30Si (n, y) 31Si ~ 31p + ~ and further 31p from decay 31Si also 31p undergo nuclear reactions (n, y) 32P. • Secondary Disorders. This type of disorder is caused by the formation of the analyzed radionuclides that do not originate from the analyte elements were intended. This can happen when the activation reactions take place in addition to (n, y), for example activation reaction (n, p) or (n, a) which is followed by decay of radionuclides produce results equal to the activation reaction (n, y). • Primary Disorders. Primary disorder is a disorder in which the most dominant APN. Type these disorders occur because the elements in the matrix of analyte undergo nuclear reactions other than the (n, y) and immediately produce radionuclides matrix analytes undergo nuclear reactions other than the (n, y) and directly produces radionuclides equal with radionuclides reaction products (n, y) desired. CHAPTER III CLOSING A. Conclusion Based on the above discussion it can be concluded that: Radioisotopes can occur naturally or intentionally (synthesis) created by humans in the research reactor. Radioisotopes are commonly used in various fields of human needs such as health, agriculture, hydrology and industry, in general, does not exist in nature, as most paronya relatively short lifespan. Radioisotope utilization in chemicals include: tracer techniques, isotope in the chemical analysis consists of the analysis of isotope dilution and neutron activation analysis (NAA). B. Suggestions For complemented content on this paper are expected criticism of readers, especially the material into the contents in this paper.