A A new analytical extraction method was developed for a DNA

A A new analytical extraction method was developed for a DNA analysis in linger print samples A finger print sample was analyzed six times using the new protocol and found to contain average value of 7580.0 mu g/L with a standard deviation of 10 for DNA A spike recovery was conducted to validate the accuracy of the new method A spike of the blood with 150 0 mu g/L DNA gave a concentration of 7725 mu g/L What is the percentage recovery of DNA spike recovery study? Based on the result of percentage recovery, will you consider the method accurate for DNA extraction?

Solution

Ans. Given,

            I. [DNA] finger print = 7580.0 µg/ mL

            II. [DNA] in spiked solution = 7725.0 µg/ mL

            III. [DNA] spiking = 150.0 µg/ mL

Note: Solution I is supposed to have an average DNA concentration of 7580.0 µg/ mL. It is further spiked with 150.0 µg/ mL DNA to make solution II. Therefore, solution II is supposed to have [DNA] of solution I + 150.0 µg/ mL. Solution II, when analyzed, gives [DNA] of 7725.0 µg/ mL.

We have to compare the theoretical concentration ([DNA] of solution I + 150.0 µg/ mL) of solution II to the experimental concentration obtained through new protocol (7725.0 µg/ mL)

So,

Actual calculated concentration of DNA in spiked solution

= [DNA] of spiked solution = [DNA] spiking

= 7725.0 µg/ mL - 150.0 µg/ mL

= 7575 µg/ mL

That is, the solution I (which is used to make solution II by spiking) practically has [DNA] = 7575 µg/ mL compared to the average values of 7580.0 µg/ mL.

Part A: % Recovery = (Actual calculated concentration of DNA in spiked solution / Standardized average concentration of DNA) x 100

                        = (7575.0 µg mL^-1 / 7580.0 µg mL^-1)x 100

                        = 99.93 %

Part B: Yes since % recovery is nearly equal to 100%, the method can be accepted for accurate DNA

As a method DNA extraction.