(a) Interpretation: The amount of protein sample hydrolyzed is 10.0g. The specific activity of the 14 C labeled threonine is 1000cpm/mg and the 3.00mg of threonine is added to the hydrolysate. After mixing the specific activity of the threonine is 20cpm/mg when the pure threonine of amount 11.5 mg was isolated. The percentage of protein which is threonine is to be determined. Concept introduction: The formula for the half time is given as- t 1 / 2 = 0.693 λ ………………….. (1) Where, λ = d e c a y c o n s t a n t The amount of inactive species is calculated by the isotope dilution method which is given as- m x = R t R m × m m − m t ………………………. (1) Here, m x = mass of inactive sample R t = counting rate R m = counting rate of inactive analyte m m = isolated mass which is purified from the mixture of radioactive tracer m t = mass of radioactive tracer

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Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213
BuyFind

Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213

Solutions

Chapter 32, Problem 32.17QAP
Interpretation Introduction

(a)

Interpretation:

The amount of protein sample hydrolyzed is 10.0g. The specific activity of the 14C labeled threonine is 1000cpm/mg and the 3.00mg of threonine is added to the hydrolysate. After mixing the specific activity of the threonine is 20cpm/mg when the pure threonine of amount 11.5 mg was isolated. The percentage of protein which is threonine is to be determined.

Concept introduction:

The formula for the half time is given as-

t1/2=0.693λ ………………….. (1)

Where,

λ=decay constant

The amount of inactive species is calculated by the isotope dilution method which is given as-

mx=RtRm×mmmt ………………………. (1)

Here,

mx = mass of inactive sample

Rt = counting rate

Rm = counting rate of inactive analyte

mm = isolated mass which is purified from the mixture of radioactive tracer

mt = mass of radioactive tracer

Interpretation Introduction

(b)

Interpretation:

The amount of protein sample hydrolyzed is 10.0g. The specific activity of the 14C labeled threonine is 1000cpm/mg and the 3.00mg of threonine is added to the hydrolysate. After mixing the specific activity of the threonine is 20cpm/mg when the pure threonine of amount 11.5 mg was isolated. The change in the answer is to be determine when the 11C with half time 20.3 min is used instead of 14C and the elapsed time for the two specific activity is 32 min.

Concept introduction:

The formula for the half time is given as-

t1/2=0.693λ ………………….. (1)

Where,

λ=decay constant

The specific activity of radioactive element is calculated by the following equation-

A=A0eλt

Or

A0=Aeλt ……………….. (2)

Where,

A0 = initial activity

A = final activity

The amount of threonine is calculated by the following formula-

mx=RtRm×mmmt ……………………….. (3)

Where,

mx = mass of inactive sample

Rt = counting rate

Rm = counting rate of inactive analyte

mm = isolated mass which is purified from the mixture of radioactive tracer

mt = mass of radioactive tracer

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