Английский. пособие Химики АЯ. Introduction
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Text 2 Active Vocabulary painstaking (adj) – доскональный, кропотливый, скрупулезный, тщательный volatilisation (n) – улетучивание emit (v) – излучать, испускать, выделять scrupulous attention (phr) – пристальное внимание cleanliness (n) – чистота solvent (n) – растворитель separation (n) – отделение, выделение, разделение, сепарирование, sensitivity (n) – чувствительность robustness (n) – надёжность, устойчивость linear range (phr) – линейный участок precession (n) – прецессия 1. Read the statement and say whether you agree or disagree with it. “It is common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something” – Franklin D. Roosevelt (American president). 2. In pairs, discuss the following questions. What do you mean by ‘method’? What methods are applied in chemistry? What do methods of analysis depend on? Which methods do you use in your analytical work? 3 (a). What do you think the methods of analytical chemistry are? What does the analysis of a material usually involve? Read the text and find out. Techniques of Analytical Chemistry Most modern analytical chemistry is quantitative. Quantitative analysis can be further split into different areas of study. The material can be analyzed for the amount of an element or for the amount of an element in a specific chemical species. 1) □ There are a bewildering array of techniques available to separate, detect and measure chemical compounds. Separation of chemicals in order to measure the weight or volume of a final product is an older process and can be quite painstaking. Measuring the absorption of light by a solution or gas, we can calculate the amounts of several species, often without separation. 2) □ Many techniques combine two or more analytical methods (sometimes called "hyphenated" methods). Examples of this include ICP–MS (Inductively-Coupled Plasma - Mass Spectrometry), where volatilisation of a sample occurs in the first step, and measuring of the concentration occurs in the second. The first step may also involve a separation technique, such as chromatography, and the second a detection/ measuring device. Techniques that involve volatilisation aim to produce free atoms of the elements making up the sample, which can then be measured in concentration by the degree to which they absorb or emit at a characteristic spectral frequency. 3) □ These techniques include atomic absorption spectroscopy and ICP-MS / ICP-AES. These techniques can still be used to study speciation, however by the incorporation of a separation stage before volatilisation. Analytical methods rely on scrupulous attention to cleanliness, sample preparation, accuracy and precision. Many practitioners will keep all their glassware in acid to prevent contamination, samples will be re-run many times over, and equipment will be washed in specially pure solvents. 4) □ If the concentration of element or compound in a sample is too high for the detection range of the technique, it can simply be diluted in a pure solvent. If the amount in the sample is below an instrument's range of measurement, the method of addition can be used. In this method a known quantity of the element or compound under study is added, and the difference between the concentration added, and the concentration observed is the amount actually in the sample. Analytical chemistry research is largely driven by performance (sensitivity, selectivity, robustness, linear range, accuracy, precession, and speed), and cost (purchase, operation, training, time, and space). A lot of effort is put in shrinking the analysis techniques to chip size. 5) □ Much effort is also put into analyzing biological systems. Examples of rapidly expanding fields in this area are: Proteomics – the analysis of protein concentrations and modifications, especially in response to various stresssors, at various developmental stages, or in various parts of the body. 6) □ Metalomics – similar to proteomics and metabolomics, but dealing with metal concentrations and especially with their binding to proteins and other molecules. 3 (b). Read the text again and choose from sentences, A– G, the one that best fits each gap 1– 6 to complete the text. There is one extra sentence you do not need to use. A These methods have the disadvantage of completely destroying the sample, and any species contained within it. B Although there are few examples of such systems competitive with traditional analysis techniques, potential advantages include size/portability, speed, and cost. C The latter is of particular interest in biological systems; the molecules of life contain carbon, hydrogen, oxygen, nitrogen, and others, in many complex structures. D Newer methods include atomic absorption spectroscopy (AAS), nuclear magnetic resonance (NMR) and neutron activation analysis (NAA). E Metabolomics – similar to proteomics, but dealing with metabolites. F The first step, sampling can be a significant problem, particularly in industrial applications. G A standard method for analysis of concentration involves the creation of a calibration curve. 4. In pairs, answer the following questions. Is modern analytical chemistry quantitative or qualitative? How can you analyze a material? What are the main methods of analytical chemistry? Can you describe them? What are the criteria for analytical methods? What do chemists take into consideration while applying analytic methods? 5 (a). Give Russian equivalents for the following English words, word combinations and chemical terms. 1) different areas of study; 2) specific chemical species; 3) molecules of life; 4) bewildering array of techniques; 5) available to separate; 6) measuring the absorption of light; 7) calculate the amounts of several species; 8) often without separation; 9) gain an understanding; 10) absorption spectroscopy; 11) nuclear magnetic resonance; 12) neutron activation analysis; 13) "hyphenated" methods; 14) volatilisation of a sample; 15) detection / measuring device; 16) produce free atoms of the elements; 17) make up the sample; 18) characteristic spectral frequency; 19) study speciation. 5 (b). Give English equivalents for the following Russian words, word combinations and chemical terms. 1) новейшие методы; 2) объединять, сочетать два и более методов; 3) измерение концентрации; 4) включение, введение, добавление; 5) специалист-практик; 6) предотвращать загрязнение; 7) градуировочная кривая; 8) дальность обнаружения; 9) разводить, разбавлять, растворять; 10) сокращение; 11) компактность; 12) в ответ на; 13) стрессогенный фактор, стрессор; 14) сцепление, связь. 6. Fill in the appropriate word(s) from the list below into the text and then translate the sentences into Russian: involve; phases; problem; procedures; second; separating; volume; Volumetric; weighing. Methods of Analysis The analysis of a complex material usually involves four steps, sampling, dissolving the sample, _____1) mutually interfering substances, and determining the constituents of interest. The first step, sampling can be a significant ____2), particularly in industrial applications. Sampling is complete when the subdivision is small enough to permit analysis. The ____3) step is the dissolving of a sample. If we know the nature of the sample we use a suitable reagent. I/Gravimetric methods involve a ___4) operation as the final measurement. Gravimetric analysis have been developed for almost everything from A(luminium) to Z(irconium). Gravimetric _____5) may be done in various ways: by precipitating, by dissolving, by removing as a volatile compound. Volumetric methods _____6) measurement of that volume of a solution of known concentration which reacts with a known amount of the sample. Such a solution is called a standard solution. ____7) techniques are now applicable to most of the elements and to many specific inorganic and organic compounds. They are widely used in all _________8) of chemistry, in medicine, and in many allied sciences. Physico-chemical methods depend upon the measurement of physical properties other than mass and ____9). Such methods are important when the simpler methods of analysis are inadequate. 7. Arrange the words in the correct order. are • a • centrifugation. • two • around • separating • Methods • solid • liquid • processes • a • and • of • filtration • and • built filter • glass, • asbestos • barrier • be • wool • sintered • paper • The • may • and • glass • others. • matting is • usually • inadequate. • Gravitational • setting particles. • enhance • used • force • the • be • centrifuge • gravitational • to • the • A • moving • can centrifuges • hundreds • Most • minute. • per • at • operate • of • revolutions tens • difficult • separations • of • revolutions • of • Extremely • thousands • per • require • of • minute. • speeds 8. Match the terms in column A with their definitions in column B.
9. Give English translation for: Методы аналитической химии могут быть классифицированы на основе различных принципов. В зависимости от массы вещества, которое используется для анализа, различают: - макрометоды, где для анализа требуется не менее 0,1 г вещества; - полумикрометоды, где требуется 0,1–0,01 г вещества; - микрометоды, где требуется 10-2–10-3 г вещества; - ультрамикрометоды, где требуется 10-6 г вещества; - субмикрометоды, где требуется 10-9 г вещества. В зависимости от вида анализа различают методы разделения и методы определения. В методах разделения основная задача – отделение мешающих компонентов или выделение определяемого компонента в виде, пригодном для количественного определения. В методах определения содержание анализируемого компонента находят в пробе без предварительного разделения. Различают химические и физико-химические методы анализа, иногда выделяя в отдельную группу физические методы. К химическим методам относят гравиметрический и титриметрические, к физико-химическим (инструментальным) – спектрофотометрические, электрохимические, хроматографические и др. 10. Make up a report about newer methods of analytical chemistry. Present it to your class. Text 3 Active Vocabulary chromatography (n) – хроматография, хроматографический анализ analyte (n) – вещество, определяемое при анализе stationary phase (phr) – неподвижная среда, носитель retention time (phr) – время удержания (хроматографируемого вещества сорбентом) distribution (n) – распределение solute (n) – растворённое вещество, раствор preparative chromatography (phr) – препаративная хроматография purify (v) – очищать contribution (n) – вклад pigment (n) – пигмент, красящее вещество, краситель underlying (adj) – лежащий в основе, основной give rise to (phr) – вызывать, иметь результаты, давать начало 1.You recently attended a lecture on chromatography. Work with your partner to discuss what you think these terms (used in tutorial) mean. Chromatography, paper chromatography, selective absorption, partial fractionation. 2. Read the text and choose the correct answer, A, B, C or D for questions 1–5. Chromatography Chromatography is a family of analytical chemistry techniques for the separation of mixtures. It involves passing the sample, a mixture which contains the analyte, in the "mobile phase", often in a stream of solvent, through the "stationary phase." The stationary phase retards the passage of the components of the sample. When components pass through the system at different rates they become separated in time, like runners in a marathon. Ideally, each component has a characteristic time of passage through the system. This is called it's "retention time." A chromatograph takes a chemical mixture carried by liquid or gas and separates it into its component parts as a result of differential distributions of the solutes as they flow around or over a stationary liquid or solid phase. Various techniques for the separation of complex mixtures rely on the differential affinities of substances for a gas or liquid mobile medium and for a stationary adsorbing medium through which they pass; such as paper, gelatin, or magnesium silicate gel. Analytical chromatography is used to determine the identity and concentration of molecules in a mixture. Preparative chromatography is used to purify larger quantities of a molecular species. History of Chromatography It was the Russian botanist Mikhail Tsvet who invented the first chromatography technique in 1901 during his research on chlorophyll. He used liquid-adsorption columns to separate plant pigments. The method was described on December 30, 1901 at the XI Congress of Naturalists and Doctors in St. Petersburg. The first printed description was in 1903, in the Proceedings of the Warsaw Society of Naturalists, section of biology. He first used the term chromatography in print in 1906 in his two papers about chlorophyll in the German botanical journal, Berichte der Deutschen botanischen Geselschaft. In 1907 he demonstrated his chromatograph for the German Botanical Society. The phenomenon of precipitational separation was observed before Tsvet as well. His contribution was turning the phenomenon into the method of scientific analysis. The Greek word chroma in chromatography means color in English and refers both to Tsvet's name that is literally translated from Russian as color and to the color of the plant pigments he was separating at that time. In 1952 Archer John Porter Martin and Richard Laurence Millington Synge were awarded the Chemistry Nobel Prize "for their invention of partition chromatography". The technology of chromatography advanced rapidly throughout the 20th century. Researchers found that the principles underlying Tsvet's chromatography could be applied in many different ways, giving rise to the different varieties of chromatography. Simultaneously, advances continually improved the technical performance of chromatography, allowing increasingly similar molecules to be resolved. Chromatography is…………………….. A the most generally useful technique for accomplishing a phase separation. B usually employed in the analysis of the gases. C a method of chemical analysis based upon the selective absorption and partial fractionation of various substances by certain suitable materials. D a special technique employed in the analysis of the gases. Chromatography involves ………………………………… A one stage. B two stages. C three stages. D four stages. The techniques of carrying out a chromatographic investigation……………………. A are not the recognized processes of chemical engineering. B are techniques of separating a solid and a liquid. C are very complex. D require a minimum of special equipment. This method was……………………………………………………… A widely used by the Greek. B developed by Archer John Porter Martin. C first described by the Russian botanist Tsvet. D demonstrated on December 30, 1901 at the Congress of Botanists. Methods of chromatography are …………………………………… A applied only in analytical chemistry. B applied to the separation processes of quantitative analysis. C applied to the separation of mixtures. D applied to most of the elements and to many specific inorganic and organic compounds. |