1. in an Agilent Ion Trap Mass Spectrometery
Capillary exit voltage-induced vs. CID fragmentation behavior of four antiviral drugs
in an Agilent Ion Trap Mass Spectrometery
Mohamed W Attwa; Nasser Salem; Ali S. Abdelhameed; A. F. M. Motiur Rahman; Adnan A. Kadi
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia
OVERVIEW
FRAGMENTATION PATTERN FOR ABACAVIR
We illustrated Abacavir as an example for comparing two fragmentation techniques (Figure 3 and Figure 4), other three antiviral results are summarized in table 3 and table 4
The fragmentation pathways of antiviral drugs were investigated and data of SID of ESI-Ion Trap and multistage fragmentation ESI-Ion Trap were compared. The detail fragmentation pathways of all ions observed in the in-source fragmentation spectrum of compounds were elucidated by further dissociation of each of these fragment ions using MS2, MS3 and MS4 fragmentation stages. The substructures of all fragment ions were unambiguously assigned. 
MS scan for Abacavir applying Capillary Exit Voltage
Product ion for 191
Product ion for 174
MS3 for 174
Penciclovir
Famciclovir
Abacavir
MS scan for Abacavir
Product ion for 287.2
MS3 for 191
MS4 for 174
MS4 for 164
MS4 for 150
Abacavir
Acyclovir
INTRODUCTION
Mass spectrometry (MS) is a very powerful technique that can be used to analyze a wide range of materials such as proteins, peptides, DNA, drugs and polymers. In an ESI Ion Trap, fragmentation can take place in the source by varying of the capillary exit voltage, whereas CID takes place in the trap to analyze the chemical fragmentations. Due to differences in the methods by which fragmentation is induced, the behavior of compounds subject to these techniques might differ. Here, we present a comparative study of the fragmentation behavior of a group of antiviral drugs, namely Famciclovir, Acyclovir, Penciclovir and Abacavir, to investigate how to extend the qualitative power of ion trap MS and to maximize the benefit from mass analyzer
METHODS
In Ion trap, product ion scan was performed before the in-source fragmentation to determine each compound’s related fragment ions, the capillary exit voltage was optimized to produce adequate in-source fragmentation. The data was compared with multi stage fragmentation using CID. Capillary exit voltage was 100 V for CID and 200 V for SID
Figure 2: MSn Fragmentation pattern of protonated abacavir.
Figure 3: In source Fragmentation pattern of protonated abacavir.
Table 4: In source Fragmentation of protonated antiviral drugs.
In-source fragmentation
MS2
MS3
Penciclovir
254.5
152.1
135, 110
110, 135
Acyclovir
226
152
135, 89.2
Famciclovir
322
135
107,116.9
202
186
262
202,136
280
202,238,262
Table 3; MSn Fragmentation of protonated antiviral drugs.
MS scan
MS2
MS3
Penciclovir
254.5
152.1
135, 110
Acyclovir
226
152
135
Famciclovir
322
136
202
186
262
136,202
280
136,202,238,262
Conclusion
Better qualitative information was obtained using capillary exit voltage fragmentation comparing to CID of ESI-Ion Trap MS for antiviral drugs.
Figure 1: The Agilent 6320 Ion Trap MS (Figure courtesy of Agilent Technologies)
We made all default parameters except capillary exit voltage which was 100V for CID and 250V for SID
LC Parameters:
MS Parameters:
Table 1: LC parameters
HPLC Model
Agilent 1200.
Injection volume
10 µl
Column
Connector
Mobile phase
A:H2O
B: ACN
Flow rate
0.4 ml/min.
Run time
5 minutes
Table 2: MS parameters
Mass detector
Agilent Ion Trap 6320
Ion source
ESI
Drying Gas(N2) Temperature & Flow
350 0C
12 l/min
Mode
Positive –
Ultra scan
Nebulizer Pressure
50 psi
Scan range
Daltons
Smart target
10,000.
Accumulation time
150 ms
62nd ASMS Conference on Mass Spectrometry and Allied Topics, June 15-19, Baltimore, USA.