Chemical Laboratory Instruments

The types of instruments commonly found in a chemical laboratory are often specific for the work conducted in a particular lab. For example, a biochemistry laboratory may include equipment for digesting organic substances, protein and DNA, into basic chemical components. However, there are a number of instruments that are commonly found in most chemical laboratories. They provide the basic instrumentation necessary for conducting chemical experiments.

Calibrated Glassware for Accurate Measurement

• Laboratory glassware includes items such as beakers, flasks, cylinders, volumetric flasks and burettes. Laboratory grade glassware is made from Pyrex, glass capable of withstanding rapid changes in temperature. Calibrated beakers and flasks are not very accurate or used for liquid measurements. Laboratory cylinders can accurately measure volumes down to 1/10 milliliter. The burette is a calibrated tube capable of delivering accurate volumes of liquid chemicals. It is typically used to add known volumes of a chemical to an unknown while measuring for a change in pH. The volume delivered through the burette is used to determine the unknown recipient chemical.

Instruments to Measure pH

• Paper with pH indicators, or chemical pH indicators were once the method for measuring whether chemicals were acid or base. However, pH paper is subjective when comparing color changes to given standard. Liquid indicators, like phenylphaline, are limited in ability to detect multiple pH measurements. The pH meter is an instrument capable of accurately determining the full range of pH. A pH meter is capable of measuring whether a chemical is an acid, base or neutral. It is often used in a recipient reagent when delivering a liquid volume from a burette. A pH meter is also useful when a specific pH is required.

Instruments to Measure Weight

• Weight measurements have become increasingly more accurate with development of the analytical balance. The double pan balance required a material to be placed on one pan while known weights were used to balance on the second pan. Accuracy of the double pan balance was limiting. The analytical balances commonly used are digital with accuracy down to four decimal places or 1 / 10,000 gram. Increasing measurements of weight have enabled scientists to reduce the size of many chemical reactions. Presently, chemical applications are measured using nano, 1/1,000,000,000 amounts.

Instruments Used for Chemical Separations

• Some chemical laboratories are equipment with instruments designed for more specific applications. Chromatography is a method designed to separate components found in a mixture. The application is designed using a non-moving, or stationary phase with particular affinity for each component found in the mixture, and a moving, or mobile phase that drives each component through the stationary phase. Mobile phases can be in many different forms. It can be gas or vapor for gas chromatography or a solvent for paper chromatography. High-pressure liquid chromatography is an excellent method of chemical separation and drives the mobile phase under high pressure. Components separated by chromatography include solvent mixtures, drug components and organic components such as protein or DNA.

Atomic Absorption

• Metal components can be quantified by burning a chemical in a flame. Flame photometry measures radiant energy for components that are difficult to measure by other laboratory instruments. It is typically used to quantify presence of metals in a mixture. The chemical to be tested is sprayed into a flame and the change in flame color is used as the determinant. For example, sodium is a metal that produces an intense yellow flame, and the intensity is linearly related to the amount of sodium present.