3.
Standard addition is one possibility to account for matrix effect. However it assumes that matrix effect is a proportional effect independent of the analyte concentration. In order to control this assumption analyst prepared both standards and post-extraction spiked samples at analyte concentration of 10 and 2.5 mg/kg.
Following results were observed:
Standard 10 mg/kg
|
Sample 10 mg/kg
|
Standard 2.5 mg/kg
|
Sample 2.5 mg/kg
|
7832180
|
6964080
|
2406174
|
827948
|
7718368
|
6722779
|
2434535
|
854663
|
7822817
|
7387993
|
2586852
|
764868
|
Question 1: Estimate matrix effect for 10 mg/kg and 2.5 mg/kg from the measured signals.
Please give the answer in percents with one decimal place and please use dot as decimals separator (i.e. please give 91.7% and not 0.917; 91|7% or 91.765%). Please do not add % in the gap as the % mark is already given after the gap.
Question 2: Can standard addition be used in this case in order to account for matrix effect?