Question

Atomic absorption spectroscopy was used to determine the amount of aluminum in a sample of sunscreen. A blank solution was measured seven times to determine the detection and quantitation limits of the spectrometer. The blank readings were: 0.0159 , 0.0081 , 0.0095 , 0.0109 , 0.0090 , 0.0114 , and 0.0090 AU. Determine the signal at the detection limit and the signal at the limit of quantitation for this method.

Answer 1

LOD = 0,0177

LOQ = 0,0345

Step-by-step explanation:

Detection limit (LOD) is defined as the lowest signal which, with a stated probability, can be distinguished from a suitable blank signal. In the same way, quantification limit (LOQ) is defined as the lowest analyte concentration that can be quantitatively detected with a stated accuracy and precision.

There are many formulas but the most used are:

LOD = X + 3σ

LOQ = X + 10σ

Where X is average and σ is standard desvation

For the blanks readings the average X is 0,0105 and σ is 0,0024

Thus:

LOD = 0,0177

LOQ = 0,0345

I hope it helps!