This instrument is used to separate all of the molecules in a sample into groups and measure the total amount of each group. Unlike HPTLC, it requires reference materials such as analytical standards in order to calibrate the instrument and method.

Just like HPLC, a UPLC instrument separates and measures molecules. However, UPLC technology uses higher pressures and smaller particles during separation to achieve better results in less time at less cost. UPLC is the modern version of HPLC, and still require reference materials for calibration.

This instrument is the same as a UPLC instrument, but the attached detector is a mass spectrometer, which measures the mass of each molecule as it gets detected, whereas traditional UPLC instruments use spectroscopic (i.e. interactions with light) techniques. Like its HPLC and UPLC brethren, UPLC-MS instruments also require the use of highly characterized reference materials.

This instrument measures the amount of material present in the space above a sample (call the headspace) inside a small vial. It is used to determine the quantity of volatile solvents present in a given sample by heating the sample to evaporate the solvents, then using Helium gas and a capillary tube to separate all of the molecules from each other, measuring the quantity of each solvent as it exits the tube. This is exclusively how residual solvents testing is performed. Like the other chromatographic instruments in the laboratory, this instrument also requires the use of highly pure and well characterized reference materials, which are consumed during every test and cannot be reused.

This instrument relies on a chemical property called absorbance whereby some molecules can absorb light of specific wavelengths in a matter in accordance with Beer’s Law. This law allows a chemist to prepare a liquid sample and place it into the instrument, specify the wavelength (or wavelengths) to be used, and the instrument measures the amount of light into and out of the sample. If the identity of the molecules being tested are known, the amount can be calculated in accordance with Beer’s Law. Under some circumstances, this test can be performed without access to any reference materials, as Beer’s Law is a property of the molecule in and of itself, and therefore valid without the need for calibration.

Like UV-Vis, FTIR is a spectroscopic technique that measures the interaction of a sample with infrared light. Since not all molecules are “UV active” meaning not all molecules absorb UV light, FTIR is a complementary technique which can help identify a material if the identity is unknown. Furthermore, if a library of spectral responses is built, previous spectra can be directly compared even for complex samples that contain more than one type of molecule.

An instrument used to measure the rotation of plane polarized light. Like UV-Vis and FTIR, polarimeter measurements are spectroscopic. Like UV-Vis, polarimetry relies on inherent properties of a molecule, and external reference materials are not necessarily required for most methods. However, only molecules that have chiral (pr. ki - rull) centers are subject to this technique, as molecules that do not have chiral centers are optically invisible to a polarimeter.

An instrument used to determine the melting point of a substance. For well prepared, pure compounds, the melting point of the material is well known. This can be indicative as to the purity of the sample.

This instrument is essentially a balance (commonly incorrectly called a scale) with a small oven on top. A sample is poured onto the balance and the oven turned on. As the sample heats, water (or assumed water) evaporates, and the material dries. After measurement is complete the per cent of mass lost can be determined. This is usually assumed to be only water, but some samples are volatile or melt, and the loss on drying measurement can be confounded.

A technique used to measure the energy of water in a material. While the LOD value indicates the amount of water present, water activity measures the energy. In order for microbial growth to occur, water must be present at a certain amount, and the water cannot be bound in the sample. Below some water activity levels, no microbial growth can occur, as not enough unbound water is present for growth.

A machine used to “freeze dry” a material. Lyophilizers are used to remove water and other volatile compounds from a sample via vacuum, which in turn lowers the temperature, and freezes the material. When creating reference materials, lyophilizers are critical in ensuring that a large batch of material can be created and preserved for the duration of the materials use. During reference material characterization, small amounts of the material are thawed and used for testing. After characterization is complete, enough remaining material exists to be used as a reference material for methods such as UPLC, which require calibration with reference materials.

This instrument is a cousin of the analytical HPLC. While the purpose of analytical HPLC is to separate and measure the amount of molecules present in a sample, the purpose of preparatory HPLC is to separate and collect each type of molecule present in a sample. The material collected can then be used for research and development, creation of reference materials in conjunction with a lyophilizer, or re-separated for better understanding of the components of the mixture as it was originally collected. Because the material input is collected back after the use of this instrument, this instrument is typically called a non-destructive technique, unlike most other analytical techniques.

A machine used to rotate and evaporate (hence the name) a sample under vacuum some that excess solvent can be removed. The output of a preparatory HPLC experiment typically has lots of excess solvent present. This machine can remove the solvent “gently” by both heating and reducing pressure, so that molecules that are sensitive to temperature can be preserved during the process.

Laboratory balances come in multiple types. Present in the lab is a microgram (µg) balance capable of measuring 0.000010g accurately and precisely. This balances is so sensitive that it can detect the analyst breathing on them during massing, and has an internal calibration scheme to recalibrate itself every time there is a temperature or pressure change in the laboratory.