Waters Xevo G2 QTof Operator's, Overview And Maintenance Manual

Waters Xevo G2 QTof

Operator’s Overview and Maintenance Guide

Revision B

Copyright © Waters Corporation 20102011

All rights reserved

Copyright notice

© 2010–2011 WATERS CORPORATION. PRINTED IN THE UNITED
STATES OF AMERICA AND IN IRELAND. ALL RIGHTS RESERVED. THIS
DOCUMENT OR PARTS THEREOF MAY NOT BE REPRODUCED IN ANY
FORM WITHOUT THE WRITTEN PERMISSION OF THE PUBLISHER.

The information in this document is subject to change without notice and
should not be construed as a commitment by Waters Corporation. Waters
Corporation assumes no responsibility for any errors that may appear in this
document. This document is believed to be complete and accurate at the time
of publication. In no event shall Waters Corporation be liable for incidental or
consequential damages in connection with, or arising from, its use.

Trademarks

ACQUITY, ACQUITY UPLC, Connections INSIGHT, ESCi, UPLC, and
Waters are registered trademarks of Waters Corporation. IntelliStart,
LockSpray, MassLynx, NanoFlow, NanoLockSpray, T-Wave, THE SCIENCE
OF WHAT'S POSSIBLE., UNIFI, Xevo, and ZSpray are trademarks of Waters
Corporation.

GELoader is a registered trademark of Eppendorf-Netheler-Hinz GmbH.
PEEK is a trademark of Victrex plc.
POZIDRIV is a registered trademark of Phillips Screw Company, Inc.
Swagelok is a registered trademark of Swagelok Company.
Super Flangeless and SealTight are trademarks of Upchurch Scientific, Inc.
TaperTip is a trademark of New Objective, Inc.
Teflon and Viton are registered trademarks of E. I. du Pont de Nemours and

Company.
Valco is a trademark of Valco Instruments, Inc.
Xylan is a registered trademark of Whitford Corporation.
Other trademarks or registered trademarks are the sole property of their

respective owners.

ii

Customer comments

Waters’ Technical Communications department invites you to tell us of any
errors you encounter in this document or to suggest ideas for otherwise
improving it. Please help us better understand what you expect from our
documentation so that we can continuously improve its accuracy and
usability.

We seriously consider every customer comment we receive. You can reach us
at [e-mail].

Contacting Waters

Contact Waters® with enhancement requests or technical questions regarding
the use, transportation, removal, or disposal of any Waters product. You can
reach us via the Internet, telephone, or conventional mail.

Waters’ contact information:

Contacting medium Information

Internet The Waters Web site includes contact

information for Waters locations worldwide.
Visit www.waters.com.

Telephone From the USA or Canada, phone 800

252-HPLC, or fax [phone].
For other locations worldwide, phone and fax

numbers appear on the Waters Web site.

Conventional mail Waters Corporation

34 Maple Street
Milford, MA 01757
USA

iii

Safety considerations

Some reagents and samples used with Waters instruments and devices can
pose chemical, biological, and radiological hazards. You must know the
potentially hazardous effects of all substances you work with. Always follow
Good Laboratory Practice, and consult your organization’s safety
representative for guidance.

Considerations specific to the Xevo G2 QTof

Solvent-leakage hazard

The source exhaust system is designed to be robust and leak-tight. Waters
recommends you perform a hazard analysis, assuming a maximum leak into
the laboratory atmosphere of 10% LC eluate.

Warning:

• To confirm the integrity of the source exhaust system, renew
the source O-rings at intervals not exceeding one year.

• To avoid chemical degradation of the source O-rings, which can
withstand exposure only to certain solvents (see “Solvents used

to prepare mobile phases” on page C-3), determine whether any

solvents you use that are not listed are chemically compatible
with the composition of the O-rings.

Flammable-solvents hazard

Warning: To prevent the ignition of accumulated solvent vapors inside

the source, maintain a continuous flow of nitrogen through the source
whenever significant amounts of flammable solvents are used during
the instrument’s operation.

Never let the nitrogen supply pressure fall below 690 kPa (6.9 bar, 100 psi)
during analyses that require flammable solvents. Connect to the LC output
with a gas-fail connector to stop the LC solvent if the nitrogen supply fails.

iv

Glass-breakage hazard

Source ion block assembly

Warning: To avoid injuries from broken glass, falling objects, or

exposure to toxic substances, never place containers on top of the
instrument or on its front covers.

High-temperature hazard

Warning: To avoid burn injuries, do not touch the source ion block

assembly when operating or servicing the instrument.

Xevo G2 QTof high-temperature hazard:

v

Hazards associated with removing an instrument from service

Warning: To avoid personal contamination with

biohazardous or toxic materials, wear chemical-resistant
gloves during all phases of instrument decontamination.

Warning: To avoid puncture injuries, handle syringes, fused silica lines,

and borosilicate tips with care.

When you remove the instrument from use to repair or dispose of it, you must
decontaminate all of its vacuum areas. These are the areas in which you can
expect to encounter the highest levels of contamination:

• Source interior

• Waste tubing

• Exhaust system

• Rotary pump oil (where applicable)

The need to decontaminate other vacuum areas of the instrument depends on
the kinds of samples the instrument analyzed and their levels of
concentration. Do not dispose of the instrument or return it to Waters for
repair until the authority responsible for approving its removal from the
premises specifies the extent of decontamination required and the level of
residual contamination permissible. Management must also prescribe the
method of decontamination to be used and the appropriate protection for
personnel undertaking the decontamination process.

You must handle items such as syringes, fused silica lines, and borosilicate
tips used to carry sample into the source area in accordance with laboratory
procedures for contaminated vessels and sharps. To avoid contamination by
carcinogenic, toxic, or biohazardous substances, you must wear
chemical-resistant gloves when handling or disposing of used oil.

Safety advisories

Consult Appendix A for a comprehensive list of warning and caution
advisories.

vi

Operating this instrument

When operating this instrument, follow standard quality control procedures
and the guidelines presented in this section.

Applicable symbols

Symbol Definition

Manufacturer

Authorized representative of the European
Community

Confirms that a manufactured product complies
with all applicable European Community
directives

Australia C-Tick EMC compliant

Confirms that a manufactured product complies
with all applicable United States and Canadian
safety requirements

Consult instructions for use

Audience and purpose

This guide is for operators of varying levels of experience. It gives an overview
of the instrument, and explains how to prepare it, change its modes of
operation, and maintain it.

Intended use

Waters designed the orthogonal-acceleration, time-of-flight Xevo™ G2 QTof
for use as a research tool to deliver authenticated mass measurement. The
Xevo G2 QTof is for research use only and is not intended for use in diagnostic
applications.

vii

Calibrating

To calibrate LC systems, follow acceptable calibration methods using at least
five standards to generate a standard curve. The concentration range for
standards should cover the entire range of QC samples, typical specimens,
and atypical specimens.

When calibrating mass spectrometers, consult the calibration section of the
operator’s guide for the instrument you are calibrating. In cases where an
overview and maintenance guide, not operator’s guide, accompanies the
instrument, consult the instrument’s online Help system for calibration
instructions.

Quality control

Routinely run three QC samples that represent subnormal, normal, and
above-normal levels of a compound. Ensure that QC sample results fall within
an acceptable range, and evaluate precision from day to day and run to run.
Data collected when QC samples are out of range might not be valid. Do not
report these data until you are certain that the instrument performs
satisfactorily.

ISM classification

ISM Classification: ISM Group 1 Class A

This classification has been assigned in accordance with CISPR 11 Industrial
Scientific and Medical (ISM) instruments requirements. Group 1 products
apply to intentionally generated and/or used conductively coupled
radio-frequency energy that is necessary for the internal functioning of the
equipment. Class A products are suitable for use in commercial, (that is,
nonresidential) locations and can be directly connected to a low-voltage,
power-supply network.

viii

EC authorized representative

Waters Corporation (Micromass UK Ltd.)
Floats Road
Wythenshawe
Manchester M23 9LZ
United Kingdom

Telephone: [phone]
Fax: [phone]
Contact: Quality manager

ix

x

Table of Contents

Copyright notice ................................................................................................... ii

Trademarks ............................................................................................................ ii

Customer comments ............................................................................................ iii

Contacting Waters ............................................................................................... iii

Safety considerations .......................................................................................... iv

Considerations specific to the Xevo G2 QTof..................................................... iv

Safety advisories................................................................................................. vi

Operating this instrument ................................................................................ vii

Applicable symbols ........................................................................................... vii

Audience and purpose....................................................................................... vii

Intended use...................................................................................................... vii

Calibrating ....................................................................................................... viii

Quality control ................................................................................................. viii

ISM classification .............................................................................................. viii

ISM Classification: ISM Group 1 Class A ...................................................... viii

EC authorized representative ........................................................................... ix

1 Waters Xevo G2 QTof Overview .......................................................... 1-1

Waters Xevo G2 QTof ........................................................................................ 1-2

IntelliStart technology..................................................................................... 1-2

ACQUITY and nanoACQUITY Xevo G2 QTof UPLC/MS systems............... 1-3

Software and data system ............................................................................... 1-6

Instrument Console ......................................................................................... 1-6

LockSpray source and ionization modes .................................................... 1-6

Electrospray ionization (ESI).......................................................................... 1-7

Atmospheric pressure chemical ionization (APCI) ........................................ 1-8

Combined electrospray and atmospheric pressure chemical

ionization (ESCi)........................................................................................ 1-9

Table of Contents xi

NanoLockSpray source and ionization modes .......................................... 1-9

Combined APPI/APCI source ....................................................................... 1-11

IntelliStart Fluidics system .......................................................................... 1-11

IntelliStart Fluidics system physical layout ................................................ 1-12

System operation ........................................................................................... 1-13

Ion optics ........................................................................................................... 1-14

Leak sensors ..................................................................................................... 1-15

Vacuum system ................................................................................................ 1-15

2 Preparing the Mass Spectrometer for Operation ........................... 2-1

Starting the mass spectrometer .................................................................... 2-2

Verifying the instrument’s state of readiness ................................................ 2-3

Monitoring the mass spectrometer LEDs....................................................... 2-3

Calibration ....................................................................................................... 2-3

Flow rates for the Xevo G2 QTof system ........................................................ 2-4

Preparing the IntelliStart Fluidics system ................................................. 2-4

Installing the reservoir bottles........................................................................ 2-4

Adjusting the solvent delivery tube positions ................................................ 2-7

Purging the pump ............................................................................................ 2-8

Rebooting the mass spectrometer ................................................................. 2-8

Leaving the mass spectrometer ready for operation ............................... 2-8

Emergency shutdown of the mass spectrometer ....................................... 2-9

3 Configuring the LockSpray Source ................................................... 3-1

Configuring the LockSpray source ............................................................... 3-2

Configuring for ESI mode ............................................................................... 3-2

Installing the ESI probe .................................................................................. 3-2

Removing the ESI probe.................................................................................. 3-6

Installing the small-bore capillary option .................................................. 3-7

xii Table of Contents

Configuring for APCI mode .......................................................................... 3-13

Installing the APCI probe ............................................................................. 3-13

Removing the APCI probe ............................................................................. 3-17

Configuring for ESCi mode .......................................................................... 3-18

Optimizing the ESI probe for ESCi operation.............................................. 3-18

4 Configuring the NanoLockSpray Source ......................................... 4-1

Overview of the NanoLockSpray source ..................................................... 4-2

Sample sprayer ................................................................................................ 4-3

Lock-spray sprayer .......................................................................................... 4-3

NanoFlow gas supply....................................................................................... 4-4

Purge gas.......................................................................................................... 4-4

Sprayer platform adjuster assembly............................................................... 4-4

Configuring the NanoLockSpray source ..................................................... 4-4

Source type selection ....................................................................................... 4-5

Advancing and retracting the sprayer platform ....................................... 4-6

Adjusting the sprayer tip position ................................................................ 4-7

Setting up the camera ...................................................................................... 4-8

Optional glass capillary sprayer ................................................................... 4-9

Plumbing the backpressure gas ...................................................................... 4-9

Installing the glass capillary sprayer ........................................................... 4-10

Fitting and loading the glass capillary......................................................... 4-11

5 Maintenance Procedures ..................................................................... 5-1

Maintenance schedule ..................................................................................... 5-3

Spare parts ......................................................................................................... 5-4

Troubleshooting with Connections INSIGHT ............................................ 5-5

Safety and handling ......................................................................................... 5-6

Preparing the instrument for working on the source ............................. 5-7

Table of Contents xiii

Removal and refitting of the source enclosure .......................................... 5-7

Removing the source enclosure from the instrument.................................... 5-7

Fitting the source enclosure to the instrument............................................ 5-10

Installing and removing the corona pin .................................................... 5-11

Installing the corona pin in the source......................................................... 5-11

Removing the corona pin from the source .................................................... 5-13

Operating the source isolation valve ......................................................... 5-14

Removing O-rings and seals ......................................................................... 5-17

Cleaning the instrument case ...................................................................... 5-17

Emptying the nitrogen exhaust trap bottle .............................................. 5-18

Inspecting the Varian roughing pump oil level ....................................... 5-20

Adding oil to the Varian roughing pump .................................................. 5-21

Replacing the Varian roughing pump’s oil and oil mist filter ............. 5-23

Emptying the roughing pump’s oil................................................................ 5-23

Replacing the oil mist filter........................................................................... 5-24

To fill the pump with oil ................................................................................ 5-26

Cleaning the source components ................................................................ 5-28

Cleaning the sampling cone assembly ....................................................... 5-29

Removing the sampling cone assembly from the source ............................. 5-29

Disassembling the sampling cone assembly................................................. 5-31

Cleaning the sample cone and cone gas nozzle ............................................ 5-34

Assembling the sampling cone assembly...................................................... 5-36

Fitting the sampling cone assembly to the source ....................................... 5-36

Cleaning the extraction cone ....................................................................... 5-38

Removing the ion block assembly from the source assembly...................... 5-38

Removing the extraction cone from the ion block ........................................ 5-41

Cleaning the extraction cone......................................................................... 5-42

Fitting the extraction cone to the ion block.................................................. 5-44

Fitting the ion block assembly to the source assembly................................ 5-45

xiv Table of Contents

Cleaning the ion block assembly ................................................................. 5-46

Disassembling the source ion block assembly.............................................. 5-46

Cleaning the ion block components .............................................................. 5-53

Assembling the source ion block assembly................................................... 5-55

Cleaning the source hexapole assembly .................................................... 5-57

Removing the ion block assembly, ion block support, and hexapole

from the source assembly ........................................................................ 5-57

Cleaning the hexapole assembly................................................................... 5-59

Fitting the hexapole assembly, PEEK ion block support, and ion

block assembly to the source assembly................................................... 5-61

Replacing the ESI probe tip and gasket .................................................... 5-63

Removing the ESI probe tip and gasket ....................................................... 5-63

Fitting the ESI probe tip and gasket............................................................ 5-65

Replacing the ESI probe sample capillary ............................................... 5-66

Removing the existing capillary.................................................................... 5-66

Installing the new capillary .......................................................................... 5-71

Cleaning the APCI probe tip ........................................................................ 5-75

Replacing the APCI probe sample capillary ............................................ 5-75

Removing the existing capillary.................................................................... 5-75

Installing the new capillary .......................................................................... 5-78

Replacing the reference probe capillary (LockSpray source) ............. 5-82

Removing the existing capillary.................................................................... 5-82

Installing the new capillary .......................................................................... 5-84

Replacing the reference probe capillary (NanoLockSpray source) ... 5-85

Removing the reference probe from the NanoLockSpray source ................ 5-85

Installing the new TaperTip and capillary................................................... 5-88

Cleaning or replacing the corona pin ........................................................ 5-90

Replacing the APCI probe heater ............................................................... 5-91

Removing the APCI probe heater ................................................................. 5-91

Fitting the new APCI probe heater .............................................................. 5-93

Replacing the ion block source heater ...................................................... 5-94

Table of Contents xv

Replacing the LockSpray source’s assembly seals ................................. 5-98

Removing the probe adjuster assembly probe and source

enclosure seals ......................................................................................... 5-98

Fitting the new source enclosure and probe adjuster assembly

probe seals.............................................................................................. 5-100

Replacing the mass spectrometer’s air filters ........................................ 5-102

Replacing the air filter inside the front door.............................................. 5-102

Replacing the air filters on the sides of the instrument............................ 5-104

Replacing the IntelliStart Fluidics tubing ............................................. 5-106

Removing the IntelliStart Fluidics tubing ................................................. 5-107

Plumbing the IntelliStart Fluidics lock-spray system............................... 5-108

Plumbing the IntelliStart Fluidics sample delivery system...................... 5-116

A Safety Advisories .................................................................................. A-1

Warning symbols ............................................................................................... A-2

Task-specific hazard warnings........................................................................ A-2

Specific warnings ............................................................................................. A-3

Caution symbol .................................................................................................. A-5

Warnings that apply to all Waters instruments ......................................... A-6

Electrical and handling symbols ................................................................. A-11

Electrical symbols .......................................................................................... A-11

Handling symbols .......................................................................................... A-12

B External Connections .......................................................................... B-1

Mass spectrometer external wiring and vacuum connections ............. B-2

Connecting the Varian oil-filled roughing pump ..................................... B-3

Making the electrical connections to the Varian oil-filled

roughing pump........................................................................................... B-6

Connecting the Edwards oil-free roughing pump ................................... B-7

Making the electrical connections to the Edwards oil-free

roughing pump......................................................................................... B-10

Connecting to the nitrogen gas supply ..................................................... B-10

xvi Table of Contents

Connecting to the collision cell gas supply ............................................. B-12

Connecting the nitrogen exhaust line ...................................................... B-12

Connecting the liquid waste line ............................................................... B-15

Connecting the EPC ...................................................................................... B-18

Connecting the workstation (systems with no ACQUITY LC) ............ B-19

Connecting Ethernet cables (systems with ACQUITY LC) .................. B-20

Input/output signal connectors .................................................................. B-20

Signal connections ......................................................................................... B-23

Connecting to the electricity source ......................................................... B-26

Connecting the NanoLockSpray source camera .................................... B-26

Installing the camera driver software .......................................................... B-27

C Materials of Construction and Compatible Solvents ................... C-1

Preventing contamination ............................................................................. C-2

Items exposed to solvent ................................................................................ C-2

Solvents used to prepare mobile phases .................................................... C-3

Index ..................................................................................................... Index-1

Table of Contents xvii

xviii Table of Contents

1 Waters Xevo G2 QTof Overview

This chapter describes the instrument, including its controls, sources
and IntelliStart™ Fluidics system.

Contents:

Topic Page

Waters Xevo G2 QTof 1-2
LockSpray source and ionization modes 1-6
NanoLockSpray source and ionization modes 1-9
Combined APPI/APCI source 1-11
IntelliStart Fluidics system 1-11
Ion optics 1-14
Leak sensors 1-15
Vacuum system 1-15

1-1

Waters Xevo G2 QTof

The Xevo™ G2 QTof Mass Spectrometry (MS) system is a hybrid, quadrupole,
orthogonal acceleration, time-of-flight (oaTOF) mass spectrometer operated by

®

Waters
Either of the following high-performance, ZSpray™, dual-orthogonal, API

sources is fitted as standard equipment:

• LockSpray™ electrospray ionization/atmospheric pressure chemical

• NanoLockSpray™ ESI source, see “NanoLockSpray source and

You can also use the optional combined APPI/APCI source with the
Xevo G2 QTof (see the Waters APPI Source Operator’s Guide Supplement).

For the instrument’s specifications, see the Waters Xevo G2 QTof Site
Preparation Guide.

IntelliStart technology

informatics software.

ionization/combined electrospray ionization and atmospheric pressure
chemical ionization (ESI/APCI/ESCi

and ionization modes” on page 1-6.

ionization modes” on page 1-9.

®

) source, see “LockSpray source

IntelliStart technology monitors instrument performance and reports when it
is ready for use.

The console software automatically mass calibrates the mass spectrometer
and displays performance readbacks to enable simplified setup of the system
for use in routine analytical and open access applications.

1

The IntelliStart Fluidics

system is built into the mass spectrometer. It
delivers sample directly to the MS probe from the LC column or from three
integral reservoirs. The reservoirs can also deliver sample through direct or
combined infusion so that you can optimize instrument performance at
analytical flow rates. An additional reservoir contains solvent for the
automated flushing of the solvent delivery system.

1. In this document, the term “fluidics” is used to describe plumbing components and fluid
pathways within and between instruments and devices.

1-2 Waters Xevo G2 QTof Overview

ACQUITY and nanoACQUITY Xevo G2 QTof UPLC/MS systems

The Waters Xevo G2 QTof is compatible with the ACQUITY UPLC® and

®

nanoACQUITY UPLC
the documentation relevant to your LC system.

The ACQUITY

®

Xevo G2 QTof UPLC®/MS system includes an ACQUITY
UPLC system and the Waters Xevo G2 QTof fitted with the LockSpray
ESI/APCI/ESCi source.

The nanoACQUITY Xevo G2 QTof UPLC/MS system includes a
nanoACQUITY UPLC system and the Waters Xevo G2 QTof fitted with the
NanoLockSpray source.

ACQUITY UPLC system

The ACQUITY UPLC system includes a binary solvent manager, sample
manager, column heater, sample organizer, detectors, and a specialized
ACQUITY UPLC column. Watersinformatics software controls the system.

For further information, see the ACQUITY UPLC System Operator’s Guide or
Controlling Contamination in UPLC/MS and HPLC/MS Systems (part
number 715001307). You can find the latter document on
http://www.waters.com; click Services and Support > Support.

systems. If you are not using either system, refer to

Waters Xevo G2 QTof 1-3

Waters ACQUITY Xevo G2 QTof UPLC/MS system:

Sample organizer (optional)

Solvent tray

Column heater

Xevo G2 QTof

Sample manager

Binary solvent manager

Access door to the fluidics pump

High voltage
connector for the
ESI probe

Probe

Source interface
sliding door

LockSpray source
enclosure

Access door to the
fluidics valves

1-4 Waters Xevo G2 QTof Overview

nanoACQUITY UPLC system

Solvent tray

Column heater

Xevo G2 QTof

Sample
manager

Access door to the fluidics pump

Access door to the fluidics valve

Source interface
sliding door

NanoLockSpray
source enclosure

Binary
solvent
manager

The nanoACQUITY UPLC system includes a binary solvent manager,
auxiliary solvent manager, sample manager, column heater, sample
organizer, detectors, and a specialized nanoACQUITY UPLC column. Waters
informatics software controls the system.

For further information, see the nanoACQUITY UPLC System Operator’s
Guide or Controlling Contamination in UPLC/MS and HPLC/MS Systems
(part number 715001307). You can find the latter document on
http://www.waters.com; click Services and Support > Support.

Waters nanoACQUITY Xevo G2 QTof UPLC/MS system:

Waters Xevo G2 QTof 1-5

Software and data system

Waters informatics software controls the mass spectrometer. The software
acquires, analyzes, manages, and distributes data from mass spectrometry,
ultraviolet (UV), evaporative light scattering, and other sources.

Waters informatics software enables these major operations:

• Configuring the instrument.

• Creating LC and MS methods that define operating parameters for a
run.

• Tuning and mass calibrating the mass spectrometer.

• Running samples.

• Monitoring sample runs.

• Acquiring data.

• Processing data.

•Reviewing data.

• Printing data.

See the online Help for more information

Instrument Console

The Instrument Console is an area within the Waters informatics software in
which you configure settings, monitor performance, run diagnostic tests, and
maintain the mass spectrometer. The instrument console functions
independently of the data and does not recognize or control the data software.
See the online Help for details.

LockSpray source and ionization modes

The LockSpray source uses lock-mass correction to acquire exact mass data.
The analyte is introduced into the source through a probe. A reference flow,
containing a compound of known mass, flows through a separate ESI probe.
An oscillating baffle allows the sprays to be analyzed as two separate data
functions. The lock-mass correction calculated from the reference data is then
applied to the analyte data set.

You can use the LockSpray source with the ESI, APCI, and ESCi ionization
modes. See Chapter 3 “Configuring the LockSpray Source”.

1-6 Waters Xevo G2 QTof Overview

Xevo G2 QTof fitted with LockSpray source:

Electrospray ionization (ESI)

In electrospray ionization (ESI), a strong electrical charge is applied to the
eluent as it emerges from a nebulizer. The droplets that compose the resultant
aerosol undergo a reduction in size (solvent evaporation). As solvent continues
to evaporate, the charge density increases until the droplet surfaces eject ions
(ion evaporation). The ions can be singly or multiply charged.

To operate the LockSpray source in ESI mode, you fit the source enclosure
with an ESI probe.

LockSpray source and ionization modes 1-7

The standard ESI probe capillary accommodates flow rates of up to 2 mL/min

APCI probe

Sample cone

Corona pin

making it suitable for LC applications in the range 100 µL/min to 2 mL/min.
To reduce peak broadening for lower-flow-rate LC applications, such as 1-mm
UPLC columns, use the optional, small-bore capillary, which can
accommodate a maximum flow rate of 200 µL/min.

Atmospheric pressure chemical ionization (APCI)

Atmospheric pressure chemical ionization (APCI) produces singly-charged
protonated or deprotonated molecules for a broad range of nonvolatile
analytes.

To operate the LockSpray source in APCI mode, you fit the source enclosure
with a corona pin and an APCI probe. Mobile phase from the LC column
enters the probe, where it is pneumatically converted to an aerosol, rapidly
heated, and vaporized or gasified at the probe tip.

APCI mode:

Hot gas from the APCI probe passes between the sample cone and the corona
pin. Mobile phase molecules rapidly react with ions generated by the corona
discharge to produce stable reagent ions. Analyte molecules introduced into
the mobile phase react with the reagent ions at atmospheric pressure and
typically become protonated (in the positive ion mode) or deprotonated (in the
negative ion mode). The sample and reagent ions then pass through the
sample cone and into the mass spectrometer.

1-8 Waters Xevo G2 QTof Overview

Combined electrospray and atmospheric pressure chemical ionization (ESCi)

In combined electrospray and atmospheric pressure chemical ionization

©

(ESCi
pin, to allow alternating acquisition of ESI and APCI ionization data,
facilitating high-throughput processing and wider compound coverage.

) mode, the standard ESI probe is used in conjunction with a corona

NanoLockSpray source and ionization modes

The NanoLockSpray source allows electrospray ionization performed in the
flow rate range of 5 to 1000 nL/min. For a given sample concentration, the ion
currents for similar experiments approximate those in normal flow rate
electrospray. However, because sample consumption is greatly reduced, the
sensitivity gains are significant when similar scan parameters are used.

Lock-mass correction with the NanoLockSpray source works as the LockSpray
source does in electrospray ionization mode.

The NanoLockSpray source enclosure consists of a sprayer—universal,
borosilicate glass capillary, or CE (see below)—mounted on a ZSpray,
three-axis manipulator.

A light within the source provides illumination for the spray, which you can
observe using the video camera mounted on the corner of the source housing.

See Chapter 4 “Configuring the NanoLockSpray Source”.

NanoLockSpray source and ionization modes 1-9

Xevo G2 QTof fitted with NanoLockSpray source:

The following options are available for the spraying capillary:

• Universal NanoFlow™ nebulizer sprayer.
This option, for flow injection or coupling to nanoACQUITY, uses a

pump to regulate the flow rate as low as 100 nL/min.

• Borosilicate glass capillary NanoFlow (nanovials).
This option uses metal-coated glass capillaries, which allow the lowest

flow rates. Usable for one sample only, they must then be discarded.

• NanoFlow capillary electrophoresis (CE) sprayer.
This option uses a make-up liquid at the CE capillary tip, which allows a

stable electrospray to occur. The make-up flow rate is less than
1µL/min.

1-10 Waters Xevo G2 QTof Overview

Combined APPI/APCI source

Atmospheric pressure photoionization (APPI) uses photons generated by a
discharge UV lamp (~10.2 eV) to produce sample ions from vaporized LC
eluent. Direct photoionization of the sample molecule occurs when the photon
energy exceeds the ionization potential of the sample molecule.

The optional dual-mode (APPI/APCI) ionization source comprises an APPI
source enclosure, which is used in conjunction with a standard APCI probe.
You can operate the source in APPI or dual-mode, which switches rapidly
between ionization modes, facilitating high-throughput analyses.

For further details, see the Waters APPI Source Operator’s Guide Supplement.

IntelliStart Fluidics system

The IntelliStart Fluidics system is built into the instrument; it controls how
sample is delivered to the source.

For standard flow applications, the system delivers sample directly to the
mass spectrometer source in one of three ways:

• From the LC column.

• From three integral reservoir bottles. Use standard reservoir bottles
(30 mL) for instrument setup and calibration. Use low-volume vials
(1.5 mL) to infuse smaller volumes.

Tip: The reservoir bottles can also deliver sample through direct or

combined infusion to enable optimization at analytical flow rates.

• From a wash reservoir, which contains solvent for automated flushing of
the instrument’s solvent delivery system.

For nanoACQUITY, the valves and pumps that make up the IntelliStart
Fluidics system introduce dead volume, which can cause unacceptable peak
broadening. For this reason, the nanoACQUITY is plumbed directly to the
NanoFlow sprayer using a suitable short piece of silica tubing.

For reference flows for both the LockSpray and NanoLockSpray source, the
IntelliStart Fluidics system delivers lock mass solution from reservoir bottle B
or, for extended operating hours, from a separate, external bottle of lock mass
solution.

Combined APPI/APCI source 1-11

IntelliStart Fluidics system physical layout

A

B

C

AA

BB

C

AA

BB

C

Water sWater s

A

A

B

B

C

C

Lock-spray selector valve

Sample selector
valve

Divert valve

Sample pump

Lock-spray pump

Sample reservoir bottles (A, B and C)

Tube guides Flow sensor

Grounded union

Access doors

The IntelliStart Fluidics system comprises the components shown in the
following figure.

IntelliStart Fluidics system components:

1-12 Waters Xevo G2 QTof Overview