Agilent Technologies 7250 User manual

Agilent Technologies
Agilent
7250 Accurate-Mass
Quadrupole
Time-of-Flight GC/MS
System
Concepts Guide

2 Agilent 7250 Q-TOF GC/MS Concepts Guide
Notices
© Agilent Technologies, Inc. 2017
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Manual Part Number
G7250-90003
Edition
First Edition, July 2017
Printed in USA
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Santa Clara, CA 95051
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Software Revision
This guide applies to the Agilent Mass-
Hunter Workstation Software -- Data Acqui-
sition for 7250 Quadrupole Time-of-Flight
program version B.03.00 or higher until
superseded.
.

Agilent 7250 Q-TOF GC/MS Concepts Guide 3
In This Guide...
The Concepts Guide presents “The Big Picture” behind the
operation of the Agilent 7250 Accurate-Mass Quadrupole
Time-of-Flight GC/MS System by helping you understand how
the hardware and software work.
1 Overview
Learn how the 7250 Q-TOF GC/MS helps you do your job.
2 Theory and Inner Workings
Learn the concepts you need to understand how the 7250
Q-TOF works.
3 Agilent 7250 Accurate-Mass Q-TOF and Performance
Learn how the 7250 Q-TOF exceeds performance measures.

4 Agilent 7250 Q-TOF GC/MS Concepts Guide

Agilent 7250 Q-TOF GC/MS Concepts Guide 5
Contents
1 Overview
System Description 8
Q-TOF applications 9
Instrument control software 10
Data analysis software 12
Reference Documentation 14
2 Theory and Inner Workings
The 7250 Q-TOF Mass Spectrometer 16
Sample Ionization Technology 18
Electrion Impact Ionization 18
LE-EI Ion Source 18
Quadrupole Collision Cell MS/MS Technology 22
Quadrupole filtration 22
Quad mass filter 24
Ion fragmention and collision cell technology 26
Collision cell 26
Time-of-Flight MS Operation 30
Proprietary INVAR flight tube 31
Detector 32
Pumping system 34
3 Agilent 7250 Accurate-Mass Q-TOF Performance
How the 7250 Q-TOF Meets Performance Measures 36
Resolving Power 36
Mass Accuracy 36
Scan Speed 36
Sensitivity 37
Dynamic Range 37

6 Agilent 7250 Q-TOF GC/MS Concepts Guide
7250 Accurate-Mass Q-TOF Design 38

7
Agilent Technologies
Agilent 7250 Accurate-Mass Quadrupole Time-of-Flight GC/MS System
Concepts Guide
1
Overview
System Description 8
Q-TOF applications 9
Instrument control software 10
Data analysis software 12
This chapter provides an overview of the Agilent 7250
Accurate-Mass Quadrupole Time-of-Flight (Q-TOF) GC/MS
system, its applications, and its data analysis system.

8 Agilent 7250 Q-TOF GC/MS Concepts Guide
1 Overview
System Description
System Description
The Agilent 7250 Accurate-Mass Quadrupole Time-of-Flight
(Q-TOF) GC/MS is a stand-alone quadrupole time-of-flight mass
spectrometer for use with the Agilent 7890 Gas Chromatograph.
The 7250 Q-TOF features:
•A new independently MS-heated high efficiency, Low Energy
Electron Impact (LE-EI) ion source capable of operating in
standard (70 eV) or low energy (9 eV to 30 eV) modes
•Both 70 eV and 15 eV tune parameters are stored in the same
tune file allowing use of both modes in different time
segments for the same sample run
•Automated fast venting, that uses nitrogen to break vacuum
thereby reducing the influx of air into the analyzer, resulting
in lower stabilization times after pump down
•Independently MS-heated hyperbolic quadrupole mass filter,
which can be heated to high temperatures, minimizing the
contamination typical with low temperature analyses
•Single hexapole collision cell
•Ion-focusing slicer to improve resolution
•A new 50% longer vacuum-insulated flight tube provides
increased resolution and uses a dual-stage ion mirror for
improved mass accuracy
•A new faster pulser than on the 7200 Q-TOF that allows
extension of the mass range up to 3000 m/z
•A new 5 GS/s sampling rate with or without Transient-Level
Peak Picking (TLPP)
•Analog detector
•Independently GC-heated GC/MS interface
•Full RoHS compliance
•Three turbomolecular vacuum pumps
•Rotary vane foreline pump
•An optional isolated dry foreline pump

Overview 1
Q-TOF applications
Agilent 7250 Q-TOF GC/MS Concepts Guide 9
The 7250 Q-TOF incorporates a hexapole collision cell blanketed
with a nitrogen and helium gas mix, to improve the ion
fragmentation prior to detection quantification. It also includes
ion optics for focusing the ions prior to the flight tube and
detector.
This configuration has advantages for many applications. The
data is interpreted through the use of the MassHunter
WorkStation software, which provides quantitative and
qualitative analyses of the data obtained.
The 7250 Q-TOF can operate in either MS (TOF) mode or MS/MS
mode. When operating in MS mode, the instrument can obtain
high resolution, accurate mass measurements, and fast full
spectrum acquisition. MS/MS mode provides high resolution,
accurate mass measurements, and fast full product ion spectra
with high sensitivity. These features make the 7250 Q-TOF a
good tool for solving complex analytical problems, resolving
structural elucidation of unknowns, and confirmation of
non-target compounds.
Q-TOF applications
The 7250 Q-TOF GC/MS combination can quantify trace organic
compounds in complex matrices. The following applications use
this type of quantification:
•Food safety and research
•Environmental contaminants studies
•Toxicology
•Forensics
•Metabolomics and Metabolomics
•Natural product research
•Human and animal doping studies
•Energy research and petrochemicals
•Homeland security
Paired with the Agilent 7890 GC, the 7250 Q-TOF delivers
sensitive, reproducible analyses of target compounds in
complex matrices. This provides the following:

10 Agilent 7250 Q-TOF GC/MS Concepts Guide
1 Overview
Instrument control software
•Femtogram-level limits of detection and quantification
•Selective quantification of target compounds in high
chemical background samples
•Improved signal-to-noise ratios in complex matrices
•Ability to meet stricter regulations on sample analytical
limits for certain applications
•Simplified operation with Agilent’s data analysis software
•Fast MS/MS operation
•Reproducible mass accuracy
The 7250 Q-TOF offers the improved sensitivity in GC/MS
analysis that is required by many commercial and regulatory
applications.
Instrument control software
The MassHunter WorkStation Instrument Control software
allows you to perform the following tasks from a single window:
Prepare the instrument
•Start and stop the instrument from the software
•Download settings to the GC and the Q-TOF in real time to
control the instrument
•Evaluate if the MS parameters are within the limits to
produce the specified mass accuracy and resolution with
a Checktune report
•Optimize MS parameters automatically (Autotune) or
manually through Agilent tuning programs and print a tune
report
•Monitor the actual conditions of the instrument
•View the real-time plot for chromatograms and instrument
parameters (both GC and MS) and print a real-time plot
report
•View the centroided line spectrum of a peak or the mass
range profile spectrum of a peak in real time