Atomic absorption spectroscopy AAS is a widely used technique for determining the concentration of various elements, including lead, in water samples. To determine the concentration of lead in a water sample using AAS, follow these steps:1. Sample collection and preparation: Collect a representative water sample from the source. The sample should be stored in a clean, acid-washed polyethylene or glass container. To minimize the risk of contamination, avoid contact with metal surfaces during sampling and storage.2. Sample digestion: Depending on the nature of the sample matrix, it may be necessary to digest the sample to convert the lead into a soluble form that can be analyzed by AAS. This typically involves adding a strong acid e.g., nitric acid to the sample and heating it to break down any organic matter and dissolve the lead.3. Calibration: Prepare a series of lead standard solutions with known concentrations, covering the expected range of lead concentrations in the water sample. These standards will be used to create a calibration curve, which will be used to determine the concentration of lead in the sample.4. Instrument setup: Set up the atomic absorption spectrometer according to the manufacturer's instructions. Select the appropriate wavelength for lead analysis usually around 283.3 nm and choose the correct hollow cathode lamp lead lamp as the light source.5. Background correction: Since AAS is sensitive to interferences from other elements and compounds, it is essential to perform background correction. This can be done using methods such as deuterium background correction or Zeeman background correction, depending on the instrument's capabilities.6. Sample analysis: Aspirate the digested water sample into the AAS instrument using a nebulizer. The nebulizer converts the liquid sample into an aerosol, which is then carried into the flame or graphite furnace. The lead atoms in the sample absorb the light from the hollow cathode lamp, and the amount of absorbed light is proportional to the concentration of lead in the sample.7. Data analysis: Compare the absorbance of the water sample to the calibration curve generated from the lead standard solutions. Use the calibration curve to determine the concentration of lead in the water sample.8. Quality control: To ensure accurate and precise results, it is essential to perform quality control checks throughout the analysis process. This may include analyzing blank samples e.g., deionized water to check for contamination, analyzing duplicate samples to assess precision, and analyzing certified reference materials to verify accuracy.By following these steps and considering factors such as sample collection, digestion, calibration, background correction, and quality control, you can accurately and precisely determine the concentration of lead in a water sample using atomic absorption spectroscopy.