Atomic absorption spectroscopy AAS is a widely used technique for determining the concentration of specific elements, such as lead, in a given sample. To determine the concentration of lead in a water sample using AAS, follow these steps:1. Sample preparation: Collect a representative water sample from the source you want to analyze. It is essential to ensure that the sample is not contaminated during collection and storage. Use a clean, acid-washed container to collect the sample and store it at a low temperature e.g., 4C to minimize any chemical changes.2. Digestion if necessary : Depending on the nature of the sample and the AAS instrument used, it may be necessary to digest the sample to break down any complex organic matter and release the lead ions. This can be done using a combination of acids, such as nitric acid HNO3 and hydrogen peroxide H2O2 , and heating the sample in a digestion block or microwave digestion system. After digestion, the sample should be cooled and filtered to remove any particulate matter.3. Dilution: Dilute the digested sample to a known volume with deionized water. This will help ensure that the concentration of lead in the sample falls within the working range of the AAS instrument.4. Calibration: Prepare a series of calibration standards containing known concentrations of lead. These standards should cover the expected concentration range of lead in the water sample. Analyze the calibration standards using the AAS instrument to generate a calibration curve, which will be used to determine the concentration of lead in the sample.5. Sample analysis: Analyze the diluted water sample using the AAS instrument. The instrument will measure the absorbance of the sample at a specific wavelength corresponding to the absorption of lead. The absorbance is directly proportional to the concentration of lead in the sample.6. Data analysis: Compare the absorbance of the water sample to the calibration curve generated in step 4. This will allow you to determine the concentration of lead in the sample. Be sure to account for any dilution factors used during sample preparation.7. Quality control: To ensure the accuracy and reliability of your results, it is essential to include quality control measures, such as analyzing blank samples deionized water , duplicate samples, and certified reference materials. This will help identify any potential sources of error or contamination in the analysis.By following these steps, you can accurately determine the concentration of lead in a water sample using atomic absorption spectroscopy.