Aplicações

This Application Bulletin describes the method of near-infrared spectroscopy in diffuse reflection for the purpose of determining residual moisture in a lyophilized pharmaceutical product. Numerous sample vials containing freeze-dried pharmaceuticals were spiked with varying amounts of water for calibration purposes. The resulting differences in the absorption wavelengths of the OH-oscillation were correlated with the water content determined by Karl Fischer titration using the algorithm of multiple linear regression (MLR).

The present Application Bulletin contains NIR applications and feasibility studies using NIRSystems devices in the pharmaceutical industry. Qualitative and quantitative analyses of a wide variety of samples are part of this bulletin. Each application describes the instrument that was originally used for the analysis, as well as the system recommended for the analysis and the results that were achieved thereby.

This Application Note describes how the accuracy of your NIR measurements can be increased with instrument calibration.

The purity of a recovered solvent (dichlormethane/methylene chloride) and two of its most important contaminants (methanol and water) are monitored with NIR spectroscopy.

This Application Note shows the determination of two important additives – butylglycol and propylheptyl alcohol – in water-soluble lacquers using Vis-NIR spectroscopy. Other lacquer constituents can also be determined in addition to the two additives.

Sulfathiazoles are sulfonamides with antibiotic effect that occur in various polymorphous forms and that are often used in veterinary medicine. This Application Note shows the differentiation between commercial and sulfathiazole form I using near-infrared spectroscopy (NIRS) with the help of the overtone frequencies of N-H stretching vibration. Form I is the least stable polymorphous form. Crystallization and polymorphism must be monitored as part of quality controls. In this, NIRS is considerably more rapid and more reliable than conventional laboratory methods.

Two of the leading pain remedies, aspirin and acetaminophen, are compared with generic samples for content uniformity testing using near-infrared spectroscopy (NIRS). The method of standard addition is used for quantification. To reduce most of the effects that stem from particle size and packing differences, second derivative spectra are used.

This Application Note demonstrates how NIR spectroscopy can be used to determine the content of coatings on nylon fibers, quickly and without requiring either sample preparation or the use of reagents. In order to suppress the effects arising from scattering on the surface coatings, one forms the second derivative spectra; the linear least-squares regression method is used to calculate the calibration function.

Near-infrared spectroscopy (NIRS) is ideally suited to monitor the hardwood and softwood content in pulp and paper products.The herein described method bases on the fact that the changes in hardwood and softwood content are reflected in the intensity of the absorption bands of cellulose. A linear least-squares regression on second derivative spectra provide results that correspond very well with those of conventional laboratory determinations. With NIRS, an analytic method is available that provides results in real time.

This Application Note describes how the accuracy of your NIR measurements can be increased with reference standards.