Part 3

Question 1

If a method is linear from 1 to 10 mM and you measure concentration at 1, 3, 5, 7, and 10 mM. How would you determine the method’s linearity?

Answer 1

Plot the measured concentrations against the known concentrations.
Calculate the regression line and determine the R² value.
Interpret the R² value to assess how well the method conforms to linear behavior over the specified concentration range (1 to 10 mM).

Question 2

If you have a known standard concentration of 50 mg/L and your method gives results of 49.5, 50.2, 50.1, 49.8, and 50 mg/L, how would you evaluate accuracy?

Answer 2

Comparing the mean to the known standard solution

Question 3

Given the following replicate measurements for a 100 mg/L sample: 99.8, 100.2, 100.0, 99.9, 100.1 mg/L, calculate the method’s precision.

Answer 3

1.581 x10^-3

Question 4

Describe how you would validate the specificity of a method used to detect a particular analyte in the presence of potential interferences.

Answer 4

Identify Potential Interferences.

Prepare samples that contain the target analyte (A) at a known concentration within the working range of the method.

Compare the response of the target analyte (A) in the spiked and non-spiked samples.

Calculate for selectivity coefficient.

Question 5

If the standard deviation of the response is (σ)0.02 and the slope (S) of the calibration curve is 0.1, calculate the LOD and LOQ.

Answer 5

LOD= 0.66, LOQ= 2