Purity Determination

1. Purity Determination As a negative concept, purity is the absence of impurity or contaminants in a substance and, hence, is not measurable directly. In many fields, for example, the manufacturing, substances are most efficient when they’re pure. In addition, the pursuit of a healthy living requires a purer environment, where purity determination is necessary to us. Although we can compare the substance with a certified pure reference sample, which may be the simplest ways to check the purity of any substance, it is sometimes incorrect and not obvious. Instead, the most accurate means of determining the purity of a substance is through the use of analytical methods, which are widely used in different territories. Fig 1 Methods of purity determination BOC Sciences can provide the purity determination services accurately and efficiently for you, by varieties of advanced analytical methods as you want. Here are some common analytical methods for purity determination: Methods based on separation techniques

2. One of the most common separation techniques is the chromatography, which gives information about the detection and determination of impurities as far as their nature and chemical behaviors are known. High performance liquid chromatography (HPLC) is the most widely used chromatography method for liquid, and Gas chromatography (GC) for gas and Thin-layer chromatography (TLC) for liquid are another two useful chromatography methods. Both the HPLC and GC have the advantage of being readily applicable on a quantitative basis, but they require more complex equipment compared with the TLC, which is simple and cheap. Another increasingly common method for purity determination is the Capillary electrophoresis (CE). Methods based on intrinsic thermodynamic properties It is an absolute approach, which can determine the total amount of impurities without detailed knowledge of these impurities. There are two convenient techniques, differential scanning calorimetry (DSC) and phase solubility analysis. DSC is used to check the presence of different polymorphic forms and to determine the total amount of solid impurities. Purity estimation is based on determination of the heat of fusion of the sample and of the change in its melting point caused by the presence of impurities. This analytical method can be performed rapidly with high precision. Phase solubility analysis has occasionally been used, and may be employed to detect contaminating substances, including isomeric species, and to estimate their concentration. Compared with DSC, its value may be limited and the procedure is more time-consuming. Methods based on spectroscopic analysis There are numerous spectroscopic analytical methods, some of which can be used to the purity determination, such as ultraviolet(UV) spectrophotometry, infrared(IR) spectrophotometry and nuclear magnetic resonance(NMR) spectroscopy. UV spectrophotometry

3. depends upon the presence of a characteristic chromophore, so it can detect impurities that contribute excessively to the absorbance value and may indicate the presence of impurities that have a negligible or distinctive absorbance. IR spectrophotometry may be used to identify and determine the proportions of geometric isomers. Meanwhile, NMR spectroscopy is also a powerful spectroscopic identification tool. BOC Sciences can provide purity determination with high quality and short period. Our experts and analysts have rich experience and intimate knowledge of analytical process. We are glad to hear from you and we’re looking forward to working with you. Reference 1. WHO Technical Report Series, No. 885 - Thirty-fifth Report(1999).“Methods used to determine the purity of chemical reference substances”. https://www.bocsci.com/solutions/purity-determination.htm