What is the m/z of leucine enkephalin and Glu-fibrinopeptide B used as lockmass on Xevo G2-XS or SYNAPT G2-Si? - WKB27224

ENVIRONMENT

• MassLynx
• UNIFI
• LCT
• LCT Premier
• LCT Premier XE
• Q-Tof Premier
• Q-Tof micro
• Q-Tof 2
• Q-Tof
• Q-Tof Ultima API
• Q-Tof Ultima Global
• Synapt HDMS
• SYNAPT G2
• SYNAPT G2 MS/HDMS
• SYNAPT G2-S MS/HDMS
• SYNAPT G2-Si MS/HDMS
• SYNAPT G2-S
• SYNAPT G2-Si
• Vion IMS QTof
• Xevo QTof
• Xevo Tof
• Xevo G2 QTof
• Xevo G2 Tof
• Xevo G2-S
• Xevo G2-S QTof
• Xevo G2-S Tof
• Xevo G2-XS
• Xevo G2-XS QTof
• Xevo G2-XS Tof

ANSWER

In Positive ion mode, as calculated by and used in MassLynx and MassLynx mass reference files, plus associated MassLynx app managers:

• Leucine enkephalin C28H37N5O7 is M/1 = 556.2771 m/z
• Glu-fibrinopeptide B is Double Charged (M+2H)/2 = 785.8426 Da; Single Charge (M+H)/1= 1570.6774 Da

 

In Positive ion mode in UNIFI and UNIFI mass reference files plus other third-party MS S/W:

• Leucine enkephalin is (M+H-1e)/1= 556.27658 Da
• Glu-fibrinopeptide B C66H95N19O26 is (M+2H-2e)/2 = 785.84206 Da; Single Charge (M+H-1e)/1 = 1570.67684 Da

 

In Negative ion mode in MassLynx:

• Leucine enkephalin C28H37N5O7 is (M-H)/1 = 554.2615
• Glu-fibrinopeptide B C66H95N19O26 is (M-2H)/2 = 783.8270; Singly charged (M-H)/1 = 1568.6617

 

In Negative ion in UNIFI:

• Leucine enkephalin C28H37N5O7 is (M-H+1e)/1 = 554.26202 Da 
• Glu-fibrinopeptide B C66H95N19O26 is (M-2H+2e)/2 = 783.82751 Da; Singly charged (M-H+1e)/1 = 1568.66229

 

ADDITIONAL INFORMATION

UNIFI takes into consideration the loss (positive ion mode) or addition (negative ion mode) of the electron.

The part numbers for leucine enkephalin and Glu-fibrinopeptide B can be found in this article.

The mass calibration reference files for SELECT SERIES Cyclic IMS and SELECT SERIES MRT instruments are electron mass corrected. Therefore electron mass corrected lockmass should be used at all times.

Instrument controlled with UNIFI and waters_connected uses electron corrected reference mass.