L11: Sample Preparation in Atomic Absorption Spectroscopy - Analytical Spectroscopy скачать в хорошем качестве

L11: Sample Preparation in Atomic Absorption Spectroscopy - Analytical Spectroscopy

Sample preparation for atomic absorption spectroscopy (AAS) is a relatively quick and easy process that involves making samples into a liquid form that can be easily dispersed as an aerosol: Solid samples Dissolve in a solvent, such as a concentrated acid like HNO3, HCl, or H2SO4. Larger samples may need to be ground or broken apart first. Liquid samples Dilute highly concentrated samples to bring them within the AAS instrument's working range. Liquid samples must also be free of particulates that could block the atomizer. Ultraviolet radiation decomposition Add a small amount of acid and hydrogen peroxide to the sample without significantly increasing the temperature. This helps avoid losses of volatile elements and low contamination levels from reagents. Some common methods for bringing samples into solution include: Acid attack, Alkali fusion followed by acid attack, and Dissolution in solvent. Once the sample is in liquid form, it can be directly injected into the AAS instrument.