Analytical ChemistryAnalytical chemistry is the branch of chemistry that mainly deals with determining the chemical composition of materials, which can be solids, liquids, gases, pure elements, compounds or complex mixtures. Additionally, chemical analysis can characterize materials by determining their molecular structures and measuring physical properties such as pH, color and solubility. Wet analysis involves the study of substances that have been immersed in a solution, and microanalysis uses substances in very small quantities. Qualitative chemical analysis is used to detect and identify one or more constituents of a sample. This process involves a wide variety of tests. Ideally, tests should be simple, straightforward, and easily performed with available instruments and chemicals. The test results can be the reading of an instrument and the observation of a physical property or a chemical reaction. Reactions used in qualitative analysis may attempt to cause a characteristic color, odor, precipitate, or gas to appear. The identification of an unknown substance is achieved when a known substance with identical properties is found. If none are found, the unknown substance must be a recently identified chemical. Tests should not use excessive amounts of material to identify. Most chemical methods of qualitative analysis require a very small amount of sample. Advanced instrumental techniques often use less than a millionth of a gram. An example of this is mass spectrometry. Quantitative chemical analysis is used to determine the quantities of constituents. Most work in analytical chemistry is quantitative. It's also the most difficult. In principle the analysis is simple. The quantity of sample is measured. In practice, however, analysis is often complicated by interferences between sample constituents, and chemical separations are required to isolate the analyte or remove interfering constituents. The choice of method depends on a number of factors: speed, cost, accuracy, convenience, available equipment, number of samples, sample size, nature of the sample and expected concentration. Because these factors are interconnected, any final choice of analytical method involves trade-offs, and it is impossible to specify a single best method for performing a given analysis in all laboratories under all conditions. Since analyzes are performed on small quantities, caution must be exercised when dealing with heterogeneous materials. Carefully designed sampling techniques must be used to obtain representative samples. Preparation of solid samples for analysis usually involves grinding to reduce particle size and ensure homogeneity and drying. Solid samples are weighed using an accurate analytical balance. Liquid or gaseous samples are measured by volume using carefully calibrated glassware or flow meters. Many, but not all, analyzes are performed on sample solutions. Solid samples insoluble in water must be chemically treated to dissolve them without any effect