Evaluating the recovery rate of heavy metals in settled dirt by inductively coupled plasma mass spectrometry (ICP-MS) requires comparing the concentration of heavy metals in your sample to the known concentration of heavy metals you spiked into the sample as a reference. For calculating the recovery rate: Recovery Rate (%) = (Detected Concentration of Heavy Metal in Spiked Sample / Known Concentration of Heavy Metal in Spiked Sample) × 10 *Detected Concentration of Heavy Metal in Spiked Sample: This is the concentration of the heavy metal you measured in your sample using ICP-MS. *Known Concentration of Heavy Metal in Spiked Sample: This is the known concentration of the heavy metal that you spiked into your sample. It's the concentration you are hoping to find if the recovery percentage of the instrument depends on the detector and generation of ICP-MS. You often spike a known concentration of the heavy metal into a set of your prepared dust samples and then analyze them alongside your actual samples.

By comparing the measured concentration in the spiked sample to the known concentration, You can find out how much of the heavy metal was retrieved during the sample preparation and analysis process. A recovery rate of 98–99% shows that all of the spiked heavy metal was recovered, while a low percentage suggests that some of it was lost or not analyzed during the study—human error during sample preparation (weighting, digestion, pouring, and serial dilution). This recovery rate is used to assess the accuracy and reliability of your analytical method for assessing heavy metals in settled dust samples.@Ravi Kumar Tiwari@ 📷

Handbook of Methods in Environmental Studies: Water and Waste Water Analysis

Hi

You can use a certified reference material (CRM) to calculate recovery of your samples.

Basically a group of researchers have kindly (for a big fee) calculated the amount of metals in a sample (for example (CRM No. 30 Gobi Kosa Dust). After you analyse such CRM sample, you compare the the certified concentration to the concentration you find and then you calculate the recovery. You can apply the same recovery percentage for your sample. There are several assumptions you need to make: The matrix needs to be similar and the range of concentrations also needs to be matched.

Another way is, as indicated by the previous response, but you need to apply the standard addition calibration method. This is, you spike increasing concentration of the metals of interest as to create a calibration plot that does not cross the origin (X=0, Y=0). Then you calculate by extrapolation the value of X, when Y is equal to zero. That value is the real concentration of the analyte in your sample. Same some assumptions need to be made: The spike form of the metal needs to match the form of the metal in the sample. Normally a very soluble form of the metal is used, metal-nitrate or metal-chloride. Secondly the sample needs to be homogenized to be spiked evenly. The standard addition methods is more tricky and time consuming than calculating recoveries with a CRM

Hope this helps