I am currently using atomic adsorption to determine levels of lead in a solution. I have read a bit about this and have found that relative standard deviation is used to assess whether for example 3 measurements of the same sample are valid. However, how is the criteria level determined for this? Or are there better ways to go about assessing how many measurements per sample are necessary for a precise and accurate measurement.
Most Atomic absorption spectroscopy software gives you the standard deviation (SD) of the measurement where AAS takes 3 reading for each sample and calculate the SD values. Good SD values normally less than 1. I advise you to measure the sample 3 times and compare the concentrations and SD values of the three measurements then you can make decision on the quality of the results.
Most Atomic Absorption Spectroscopy (AAS) read three times each sample to get the result. If your gain (%) is low, you can read several times that your results will be very close, but if they are high you will have a larger swing of results. Furthermore, when you make the calibration curve, you can check the statistical information of your curve (right-clicking on the curve).
Hope this helps.
Regards,
Carlos E R Barquilha
The most important thing is that you perform your experiments in replicate, properly handle the AAS, and be careful when preparing the calibration curve and sample dilution.
Hany Fathy Heiba Is this regular standard deviation or relative standard deviation
Allie Novak the smaller values of SD thebetter results. Actually SD or RSD values less than unity is a very good result.
It is better the relative standard deviation (RSD) because it is a standardized measure of dispersion.