Since you prepared a 1L sample, 0.577 mg is the total amount of Cu in your weighed in sample.

Therefore the concentration is 0.577 mg of Cu per 0.1 g of sample.

For 100 g of your sample the amount of Cu would be (100g / 0.1 g) * 0.577 mg = 577 mg (or 0.557 %)

To calculate the percentage of an element in a sample using Atomic Absorption Spectroscopy (AAS), you first prepare a series of standard solutions with known concentrations and record their absorbance values to generate a calibration curve, which relates absorbance to concentration. Next, measure the absorbance of the unknown sample, and use the calibration curve to determine its concentration. Finally, calculate the percentage of the element in the sample using the formula: (Concentration of Element in Sample / Total Sample Mass) × 100. For example, if the element's concentration is 50 mg/L and the total sample mass is 500 mg, the percentage of the element would be 10%.

While true in this case, you need to factor in the volume of your solution. For example we often prepare ICP-MS solutions with 50 ml Volume. Our concentrations obtained by the instrument are in mg/L, therefore, we need to divide them by a factor of 20 (1000ml/50 ml)

@Priyanka Panth

Thanks dear. Is there any way to find the best sample weight?

The percentage of copper (Cu) in your original 100 g sample is calculated to be 0.577%, based on the AAS result of 0.577 mg/L from a 0.1 g sample diluted to 1000 mL. This indicates that there are 577 mg of Cu in 100 g of the sample.