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Specific absorbance

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  410

2026-11-09

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Specific absorbance

The specific absorbance can be used to calculate the sample concentration, using the absorbance measured in the specified solvent. A check on the accuracy of the absorbance scale is clearly essential. Wavelength accuracy is not so important. The practical usefulness of reference-specific absorbance values (A¹₁) clearly depends on a number of factors. These include the state of purity of the substance, the solvent conditions originally used to establish the reference data, the precise conditions employed in the reference instrument and the extent to which they correspond with those of a particular test laboratory. It is therefore wise to ascertain the status of any absorptivity data in the literature. If a sample of the drug concerned is available in pure form, it is good practice to establish periodically a ‘local’ value of the absorptivity and to use this in calculating sample concentrations.