Analytical chemistry

• Analytical chemistry is a measurement science consisting of a set of powerful ideas and methods that are useful in all fields of science, engineering, and medicine.
• Qualitative Analysis establishes the chemical identity of the species in the sample.
• Quantitative Analysis determines the relative amounts of these species, or analytes, in numerical terms.
• Analytes are the components of a sample that are determined.
• Chemistry is the science that deals with the study of the changes in composition which matter undergoes and the transformation of energy accompanying these changes.
• Matter is anything that occupies space and has mass (Solid, Liquid, Gas).
• Physical changes involve changes in form and appearance, but without affecting their chemical nature.
• Chemical changes involve changes in its composition.
• Atom is the smallest particle of an element which enters into a chemical combination, composed of a nucleus and around it revolves the electrons.
• Molecule is the smallest particle of matter that can exist in a free state capable of entering into chemical change and is a combination of atoms of the same kind or different atoms.
• Element is the simplest particle of matter which is incapable of being divided and can enter into chemical combination.
• Mixture is a mass of ingredients with a variable proportion; a Heterogeneous mixture is a combination of 2 or more substances which can be separated one from the other by mechanical means (Filtration, floatation, centrifugation, distillation, fractional distillation, fractional distillation, fractional crystallization, chromatography).
• Homogenous mixture is a combination of 2 or more substances which cannot be separated from one another by mechanical means, even by filtration and decantation.
• Compound is a combination of two or more elements at a definite proportion.
• Compounds cannot be separated into their component substance by chemical means.
• Compounds are homogenous in composition.
• Compounds have definite proportion by weight of the substance from which they were made.
• According to the number of elements present, compounds can be classified as Binary, Ternary, Quaternary.
• According to form, compounds can be Isomorphous, Polymorphous, Metamorphous, Isomeric, or Polymer.
• Feedback loop is the cycle of measurement, comparison, and control.
• Converting the analyte in such materials into a soluble form is often the most difficult and time-consuming task in the analytical process.
• A scheme must be devised to isolate the analytes from interferences before the final measurement is made.
• The process of determining k is thus an important step in most analyses; this step is called a calibration.
• This problem can certainly be the most demanding aspect of an analysis.
• Interferences are species other than the analyte that affect the final measurement.
• The solvent should dissolve the entire sample, including the analyte, rapidly and completely.
• Calculating results in analytical chemistry is based on the raw experimental data collected in the measurement step, the characteristics of the measurement instruments, and the stoichiometry of the analytical reaction.
• Once we have the sample in solution and converted the analyte to an appropriate form for measurement, the next step is to eliminate substances from the sample that may interfere with measurement.
• Replication improves the quality of the results and provides a measure of their reliability.
• Replicate samples or replicates are portions of a material of approximately the same size that are carried through an analytical procedure at the same time and in the same way.
• Interferences or interferents is a species that causes an error in an analysis by enhancing or attenuating (making smaller) the quantity being measured.
• Experimenter must provide some measure of the uncertainties associated with computed results if the data are to have any value.
• Calibration is the process of determining the proportionality between analyte concentration and a measured quantity.
• All analytical results depend on a final measurement X of a physical or chemical property of the analyte.
• Feedback system is the process of continuous measurement and control.
• Most analyses are performed on solutions of the sample made with a suitable solvent.
• The measurement of the property is directly proportional to the concentration, that is, cA = kX.
• Sample may require heating with aqueous solutions of strong acids, strong bases, oxidizing agents, reducing agents, or some combination of such reagents.
• Quantitative measurements on replicates are usually averaged, and various statistical tests are performed on the results to establish their reliability.
• Conditions resulting in metabolic alkalosis include prolonged vomiting, upper duodenal obstruction, prolonged diuretic therapy (loop diuretic), cystic fibrosis, mineralocorticoid (primary and secondary hyperaldosteronism, bilateral adrenal hyperplasia), glucocorticoid excess (primary adrenal adenoma or Cushing syndrome and disease, excessive licorice ingestion, Barterr syndrome), and high doses of bicarbonate, sodium citrate, antacids, carbenicillin or penicillin.