
[ CARE AND USE MANUAL ]
Intact mAb Mass Check Standard
CONTENTS
I. INTRODUCTION
II. STORAGE AND STABILITY
III. RECONSTITUTION OF THE INTACT 
mAB MASS CHECK STANDARD FOR  
MS OPTIMIZATION
IV. MOLECULAR WEIGHT INFORMATION
V. EXAMPLES OF USING THE INTACT 
mAB MASS CHECK STANDARD FOR  
MS OPTIMIZATION WITH Q-Tof,  
Tof AND SQD
VI. ORDERING INFORMATION
I. INTRODUCTION
A monoclonal antibody is a glycosylated protein with a molecular 
weight of about 150 kDa. Intact mass analysis of mAb by LC/MS is a 
routine analytical task performed by many different biopharmaceutical 
organizations, and provides a rapid method to investigate the integrity 
of the biological sample. Low molecular weight protein standards that 
are commonly available for instrument tuning or performance checking 
(e.g. myoglobin) are not well suited to check the instrument performance 
when the analysis of monoclonal antibody is needed because analytical 
(instrument) conditions may greatly deviate from that for mAb analysis 
due to molecular weight and structure difference ( e.g. glycosylation). 
The Intact mAb Mass Check Standard is a LC/MS standard used as a 
qualitative tool for intact mass analysis. It is an intact mouse protein 
purified by Protein-A with a known molecular weight, ideal for higher 
molecular weight intact mass measurements. It is provided in a Waters Max 
Recovery Vial (PN 18600327c). 
Upon a simple reconstitution step at a customer site, the mAb sample 
is ready for injection/analysis as a true intact mAb reference standard. 
Because the mAb sample has a similar MW range to conventional 
therapeutic monoclonal antibodies, it serves a convenient reference 
sample for MS instrument tuning and calibration check for intact mass 
analysis of high molecular weight proteins.
 

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II. STORAGE AND STABILITY
The lyophilized powder is recommended to be stored long term 
at -20 °C until the expiration date printed on the label. Once 
reconstituted, the solution is stable for one week when stored at 8 °C. 
III. RECONSTITUTION OF THE INTACT mAB MASS 
CHECK STANDARD FOR MS OPTIMIZATION
The Intact mAb Mass Check Standard is 1 mg per vial of a 
lyophilized solid. Depending on system requirements please 
follow the below solubilization instructions:
SYNAPT G1/G2 and Xevo G1/G2
Add 100 µL of DI water to the Max Recovery Vial. Sonicate for 5 
minutes. The mAb concentration of this solution will be 10 mg/ 
mL or 67 µM. Dilute this solution 20 fold with Eluent A of the LC 
mobile phase to prepare a solution containing 3.3 µM mAb and 
inject 5-20 µL for testing the LC/MS system.
SYNAPT/Xevo G2-S
Add 100 µL of DI water to the Max Recovery Vial. Sonicate for  
5 minutes. The mAb concentration of this solution will be 10 mg/mL 
or 67 µM. Dilute this solution 200 fold with Eluent A of the LC 
mobile phase to prepare a solution containing 0.33 µM mAb  
and inject 5-20 µL for testing the LC/MS system.
SQD
Add 200 µL of DI water to the Max Recovery Vial. Sonicate for  
5 minutes. The mAb concentration of this solution will be 5 mg/ 
mL or 33 µM. Inject 5-10 µL for testing the LC/MS system.
V. EXAMPLES OF USING THE INTACT mAB 
 MASS CHECK STANDARD FOR MS  
 OPTIMIZATION WITH Q-Tof, Tof AND SQD
Table 1: Deconvoluted MW of the Major Glycoform of the mAb
Peak Number mAb Glycoform Expected MW
1
M + G0F + G0F
2 M + G0F + G1F 148,383
3 M + G1F + G1F 14 8, 545
4
M + G1F + G2F
5 M + G2F + G2F 148,868
*aglycosylated mAb
ESI-TOF 
MS spectrum 
2200
Deconvoluted 
TOF spectrum 
2600 3000 3400 3800
+50 
+53 
+47 
2 
3 
1 
4
5 
148,220
148,707
m/z
IV. MOLECULAR WEIGHT INFORMATION
Light Chain Formula:  Avg. MW =  
C
106 6 H164 9 N287 O343 S7
Heavy Chain Formula:    Avg. MW =  
C
2170 H3338 N562 O661 S19
Intact Protein Formula:   Average MW = 
C
6472 H9940 N169 8 O2008 S52
Total number of Disulfide Bond = 17 
Fixed Modification on 2 x Pyroglutamic Acid Q
For sequence information to cut/paste please go to:
http://www.waters.com/waters/nav.htm?cid=134634380 and 
Click on Intact mAb Mass Check Standard.
2
Intact mAb Mass Check Standard
     2419 8 Da
    484848 Da 
   145,330 Da 
147600 148000 148400 148800 149200 149600
Mass (Da) 
Figure 1: Example Data obtained with ESI-TOF Instrumentation.
mass
 

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ESI-Quad MS spectrum 
56+
57+
58+
70+
50+
60+
2000 2100 2200 2300 24 00 2500 2600 2700 2800 2900
Deconvoluted Quad spectrum 
G0F/G0F
G1F/G1F + G0F/G2F
G0/G0F
147800 148000 148200 148400 148600 148800 149000
Mass (Da) 
Figure 2: Example Data obtained with ESI-QUAD Instrumentation.
VI. ORDERING INFORMATION
m/z
G1F/G2F
G2F/G2F
mass
Description Part Number
Intact mAb Mass Check Standard
186006552
Waters and The Science of W hat’s Possible are registered 
trademarks of Waters Corporation. Q-Tof is a trademark of  
Waters Corporation.
©2013 Waters Corporation. Produced in the U.S.A. 
September 2013 720004420EN Rev. C KP-PDF
Waters Corporation 
34 Maple Street 
Milford, MA 01757 U.S.A. 
T: 1 508 478 2000 
F: 1 508 872 1990 
www.waters.com