The internal standard method of analysis was employed in GC for the determinatio

Question

The internal standard method of analysis was employed in GC for the determination of TODD in river water. An analog ot TODD was used as an internal standard. The responses were 55 and 34 for the standard and the internal standard respectively. The internal standard procedure was as follows: 1.0 mg of internal standard was added to 2.0 mg of standard volume of 10.0 L. The internal standard was added to the unknown and the response Was 29 for the unknown and 25 for the internal standard. Find the concentration (in ppm the unknown?

Explanation / Answer

Formula: Ax /[X] = F(As / [S])

Ax is response of standard

[X] is the concentration fo standard

F is response factor

As is response of internal standard

[S] is the concentration fo internal standard

First calculate the F:

(55/2.0 mg) = F (34/1.0 mg)

F = 0.81

For Unknown:

Ax /[X] = F(As / [S])

29/[X] = 0.81(25/1.0 mg)

[X] = 1.4 mg

Concentration of unknown is 1.4 mg/10.0 L = 0.14 mg/L = 0.14 ppm

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.