ANACHEM LAB

• For analysis in the laboratory, the gross sample is usually reduced in size and homogenized to create the laboratory sample.
• Analytical Chemistry is a measurement science consisting of powerful ideas and methods that are useful in all fields of science and medicine.
• Analytical Chemistry deals with methods for determining the chemical composition of samples of matter.
• Analytical Chemistry is applied throughout industry, medicine, and all the sciences.
• Quantitative analysis measurements play a vital role in chemistry, biochemistry, biology, geology, physics, and the other sciences.
• Many scientists devote much time in the laboratory gathering quantitative information about systems that are important and interesting to them.
• Qualitative Analysis reveals the identity of the elements and compounds in the sample.
• Quantitative Analysis indicates the amount of each substance in a sample.
• The results of a typical quantitative analysis are computed from two measurements: the mass or the volume of sample to be analyzed and the measurement of some quantity that is proportional to the amount of analyte in the sample, such as mass, volume, intensity of light, or electrical charge.
• Analytical methods can be classified according to the nature of this final measurement.
• Gravimetric Methods determine the mass of the analyte or some compound chemically related to it.
• Volumetric Methods determine the volume of a solution containing sufficient reagent to react completely with the analyte.
• Sampling Methods are a crucial part of Analytical Chemistry.
• Radiation ( alpha, beta, gamma)
• SPECTROSCOPIC METHODS: Based on measurement of the interaction between electromagnetic radiation and analyte atoms or molecules or on the production of such radiation by analytes.
• mass - to - charge ratio
• ASSAY: The process of determining how much of a given sample is the material indicated by its name.
• sample thermal conductivity
• optical activity
• SAMPLING: Involves obtaining a small mass of a material whose composition accurately represents the bulk of the material being sampled.
• BASE: Power of Hydroxyl, High Hydroxyl but low Hydrogen
• Liquid samples are subject to solvent evaporation.
• Few chemical or physical properties of importance in chemical, analysis is unique to a single chemical species are referred to as interferences or interferents.
• rate of radioactive decay
• Extraordinary measures, including sample manipulation and measurement in an inert atmosphere, may be required to preserve the integrity of the sample.
• ELECTROANALYTICAL METHODS: Involve the measurement of such electrical properties as voltage, current, resistance, and quantity of electrical charge.
• It is a good idea to dry samples just before starting an analysis.
• Replicates: 3 (laboratory), 6 (statistically), 9 (research).
• STEPS IN A QUANTITATIVE ANALYSIS: Picking a method involves considering the level of accuracy required, the number of samples to be analyzed, and the complexity of the sample and the number of components in the sample.
• Under most circumstances, the sample must be processed in a variety of different ways.
• NEUTRALIZATION: Same amount of OH - & H+
• The sample may require heating with aqueous solutions of strong acids, strong bases, oxidizing agents, reducing agents, or some combination of such reagents.
• It may be necessary to ignite the sample in air or oxygen or perform a high-temperature fusion or the sample in the presence of various fluxes.
• HETEROGENEOUS MATERIAL: If its constituent parts can be distinguished usually or with the aid of a microscope.
• A solid sample is ground, mixed to ensure homogeneity, and stored for various lengths of time before analysis begins.
• heat of reaction (exothermic & endothermic)
• If the analyte is a gas dissolved in a liquid, the analyte must be kept inside a second sealed container to prevent contamination by atmospheric gases.
• Ideally, the solvent should dissolve the entire sample, including the analyte, rapidly and completely.
• MISCELLANEOUS METHODS:
• Quantitative measurements in replicates are usually averaged and various statistical tests are performed on the results to establish their reliability.