What method do laboratories use to analyze dust samples?

The method commonly used by laboratories to analyze dust samples for lead content is acid digestion. This technique involves treating the dust samples with strong acids to dissolve the materials and release metals like lead into solution. Once the substances are digested, further analytical methods, such as atomic absorption spectroscopy or inductively coupled plasma mass spectrometry, can be employed to determine the concentration of lead in the sample. Acid digestion is particularly effective because it allows for the complete dissolution of various types of materials that can be present in dust, providing a clear and comprehensive analysis of lead content.

Other methods mentioned, while critical in different contexts, do not serve the same purpose in the analysis of dust samples as acid digestion does. For example, spectroscopy is a technique that can be employed after digestion to analyze the solution, but it is not the initial step of breaking down the dust sample itself. Chromatography is typically used for separating and identifying compounds in mixtures, while microscopy focuses on visualizing the physical structure of samples rather than quantifying the chemical content. Thus, acid digestion remains the foundational method for preparing dust samples for lead analysis.