Question

38: An electrospray–transmission quadrupole mass spectrum of the a chain of hemoglobin from acidic solution exhibits nine peaks corresponding to MHn1n . Find the charge, n, for peaks A–I. Calculate the molecular mass of the neutral protein, M, from peaks A, B, G, H, and I, and find the mean value.

Short answer

The answer is not given in the drive.

Step-by-step solution

Solving for equations:

To compute for the charge of each of the different peaks, e use equation 1:

$\mathrm{n}=\frac{{\mathrm{m}}_{\mathrm{n}+1}-1.008}{{\mathrm{m}}_{\mathrm{n}}-{\mathrm{m}}_{\mathrm{n}+1}}$ equation (1)

N is charge of the peak,

${\mathrm{m}}_{\mathrm{n}}$is the m/z of the peak of interest

${\mathrm{m}}_{\mathrm{n}+1}$is the m/z of the peak with a lower m/z of 1 compared to the peak interest

computing molecular mass:

To compute for the molecular mass that corresponds to each peak, we use equation 2:

$\mathrm{M}=\mathrm{n}\left({\mathrm{m}}_{\mathrm{n}}-1.008\right)$ equation (2)

Where

M is the molecular mass that corresponds to the peak

N is charge of the peak,

${\mathrm{m}}_{\mathrm{n}}$is the m/z of the peak of interest

solving for mn and mn+1 :

First we determine the ${\mathrm{m}}_{\mathrm{n}}$and ${\mathrm{m}}_{\mathrm{n}+1}$of the different peaks,

Peak	m/z	${\mathrm{m}}_{\mathrm{n}}$	${\mathrm{m}}_{\mathrm{n}+1}$
A	1261.5	1261.5	1164.6
B	1164.6	1164.6	-
C	-	-	-
D	-	-	-
E	-	-	-
F	-	-	-
G	834.3	834.3	797.1
H	797.1	797.1	757.2
I	757.2	757.2

solving for charge:

Compute for the charge of each peak:

Peak

${\mathrm{m}}_{\mathrm{n}}$

${\mathrm{m}}_{\mathrm{n}+1}$

n

A	1261.5	1164.6	$$\begin{gathered} =\frac{1164.6-1.008}{1261.5-1164.6} \\ =12.008 \end{gathered}$$
B	1164.6	-	-
C	-	-	-
D	-	-	-
E	-	-	-
F	-	-	-
G	834.3	797.1	role="math" localid="1663658936753" $$\begin{gathered} =\frac{797.1-1.008}{834.3-797.1} \\ =21.400 \end{gathered}$$
H	797.1	757.2	$\begin{array}{l}=\frac{757.2-1.008}{797.1-757.2}\\ =18.952\end{array}$
I	757.2	-	-

corrected n:

Corrected n are;

Peak	${\mathrm{m}}_{\mathrm{n}}$	${\mathrm{m}}_{\mathrm{n}+1}$	n
A	1261.5	1164.6	12

B	1164.6	-	13
C	-	-	14
D	-	-	15
E	-	-	16
F	-	-	17
G	834.3	797.1	18
H	797.1	757.2	19
I	757.2	-	20