To determine the concentration of lead Pb in a water sample collected from a river using atomic absorption spectroscopy AAS , you will need to follow these steps:1. Collect the water sample: Take a representative water sample from the river, ensuring that it is collected in a clean container to avoid contamination.2. Prepare the sample: Depending on the AAS instrument and the specific method used, you may need to filter the sample to remove any suspended particles or perform an acid digestion to break down any organic matter and release the lead ions into solution.3. Prepare calibration standards: Prepare a series of lead standard solutions with known concentrations, typically in the range of 0 to 50 g/L micrograms per liter or as appropriate for the expected concentration of lead in the river water. These standards will be used to create a calibration curve.4. Measure absorbance: Measure the absorbance of each calibration standard and the water sample using the AAS instrument. The instrument will measure the amount of light absorbed by the lead ions in the sample at a specific wavelength 283.3 nm for lead .5. Create a calibration curve: Plot the absorbance values of the calibration standards against their respective concentrations. This will create a calibration curve, which can be used to determine the concentration of lead in the water sample.6. Determine the concentration of lead in the water sample: Using the absorbance value of the water sample, find the corresponding concentration on the calibration curve. This will give you the concentration of lead in the water sample.7. Report the results: Report the concentration of lead in the water sample, typically in units of g/L or ppb parts per billion .Note that the accuracy and precision of the results will depend on the quality of the AAS instrument, the method used, and the skill of the operator. It is essential to follow proper quality control procedures, such as analyzing blanks and reference materials, to ensure the reliability of the results.