Agilent Technologies G1289 User manual

Agilent 7694 Headspace Sampler
Operating Manual
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Agilent Technologies, Inc.
2850 Centerville Road
Wilmington, DE 1 808-1610
USA
© Agilent Technologies 2000
All Rights Reserved. Reproduction,
adaptation, or translation without
permission is prohibited, except as
allowed under the copyright laws.
Part number 1290-90317
First Edition, 3/2000
Replaces Part No. 1290-90310,
Operating and Service Manual, and part
No. 1883-90310, Operating and
Service Manual.
HP® is a registered trademark of
Hewlett-Packard Co.
Silcosteel® is a registered trademark of
Restek Corp.
Swagelok® is a registered trademark of
Swagelok company.
Printed in USA
Safety Information
The Agilent Technologies 7694
Headspace Sampler meets the following
IEC (International Electrotechnical
Commission) classifications: Safety
Class 1, Transient Overvoltage
Category II, and Pollution Degree 2.
This unit has been designed and tested in
accordance with recognized safety
standards and designed for use indoors.
If the instrument is used in a manner not
specified by the manufacturer, the
protection provided by the instrument
may be impaired. Whenever the safety
protection of the Agilent 7694 has been
compromised, disconnect the unit from
all power sources and secure the unit
against unintended operation.
Refer servicing to qualified service
personnel. Substituting parts or
performing any unauthorized
modification to the instrument may
result in a safety hazard. Disconnect the
AC power cord before removing covers.
The customer should not attempt to
replace the battery or fuses in this
instrument. The battery contained in this
instrument is recyclable.
Safety Symbols
Warnings in the manual or on the
instrument must be observed during all
phases of operation, service, and repair
of this instrument. Failure to comply
with these precautions violates safety
standards of design and the intended use
of the instrument. Agilent Technologies
assumes no liability for the customer’s
failure to comply with these
requirements.
WAR I G
A warning calls attention to a condition
or possible situation that could cause
injury to the user.
CAUTIO
A caution calls attention to a condition
or possible situation that could damage
or destroy the product or the user’s
work.
+Indicates a hot surface
*Indicates earth (ground) terminal
Sound Emission Certification for
Federal Republic of Germany
Sound pressure Lp < 68 dB(A)
During normal operation
At the operator position
According to ISO 7779 (Type Test)
Schallemission
Schalldruckpegel LP < 68 dB(A)
Am Arbeitsplatz
Normaler Betrieb
Nach DIN 45635 T. 19 (Typprüfung)

i
Contents
Chapter 1 About This Manual
Manual Overview ....................................................................................................... 2
Intended User ............................................................................................................ 3
Conventions ............................................................................................................... 3
Chapter 2 Introduction to Headspace and to the
7694 Headspace Sampler
Overview of Headspace Analysis ............................................................................ 6
The 76 4 Headspace Sampler .................................................................................. 7
Oven (G128 /G12 0) ......................................................................................... 7
Heated Zones (G1883) ...................................................................................... 8
Vial Tray (G128 /G12 0) ...................................................................................
Vial Transport Arm (G128 /G12 0) .................................................................
Sampling System ............................................................................................. 10
Transfer Line .................................................................................................... 10
Keypad and Display ......................................................................................... 10
Pneumatics ....................................................................................................... 11
Principles of Operation ........................................................................................... 13
General Operation ........................................................................................... 13
Power on Diagnostics ..................................................................................... 14
Standby Condition ........................................................................................... 14
Vial Pressurization ........................................................................................... 15
Filling the Sample Loop .................................................................................. 16
Loop Equilibration ........................................................................................... 17
Injecting the Sample ........................................................................................ 17
End of Cycle and Vial Recovery .................................................................... 18
Modes of Operation ................................................................................................. 1
Standard Headspace Extraction .................................................................... 1
Multiple Headspace Extraction with Multiple Vial Puncture–
G128 /G12 0 only ............................................................................................ 21
Multiple Vial Puncture with Constant Heating Time–G128 /G12 0 only . 22
Multiple Headspace Extraction with Single Vial Puncture ........................ 23
Multiple Headspace Extraction for Analyte Concentration–
G128 /G12 0 only ............................................................................................ 23

Contents
ii
Chapter 3 The eypad
Accessing Functions ................................................................................................26
Editing Setpoints ......................................................................................................26
The G1883 Keypad ...................................................................................................26
The G128 /G12 0 Keypad .......................................................................................28
Keys and Their Functions .......................................................................................30
Start (G1883 only) ............................................................................................30
Stop/Reset (G1883 only) .................................................................................30
Start/Stop (G128 /G12 0 only) .......................................................................30
Zone Temps .....................................................................................................31
Event Times .....................................................................................................32
Vial Parameters ...............................................................................................34
Load Method ....................................................................................................35
Store Method ...................................................................................................35
Chain Methods ................................................................................................36
Link Methods ..................................................................................................36
Carousel Advance (G1883 only) .....................................................................36
Pressure (G1883/G12 0 only) .........................................................................36
Tray Advance (G128 /G12 0 only) ................................................................36
Enter ................................................................................................................37
Clear .................................................................................................................37
Numeric Keypad ...............................................................................................37
Adv Fctn { } ......................................................................................................37
Chapter 4 Using the Adv Fctn ey
Using an Advanced Function .................................................................................40
List of Advanced Functions by Model ...................................................................41
Advanced Function Descriptions ..........................................................................44
Chapter 5 Preparing a Sample
Sample Preparation .................................................................................................56
Loading the Sample Tray and/or Carousel ...........................................................58

Contents
iii
Chapter 6 Entering a Method
Entering a Method ................................................................................................... 60
Entering Zone Temps ...................................................................................... 60
Setting Event Times ........................................................................................ 61
Setting Vial Parameters .................................................................................. 63
Storing and Loading Methods ................................................................................ 64
Storing a Method ............................................................................................. 64
Loading a Method ............................................................................................ 64
Chaining Methods .................................................................................................... 65
Activate a Method Chain ................................................................................ 65
Deactivate a Method Chain ............................................................................ 66
Using a Method Chain for MHE ............................................................................. 66
Using a Method Chain for Running More Than 44 Samples .............................. 66
Chapter 7 Developing Methods
Varying Oven Temperature .................................................................................... 71
Varying Event Times ............................................................................................... 71
Vial Equilibration Time ................................................................................... 71
Loop Fill Time .................................................................................................. 72
Matrix Effects .......................................................................................................... 72
Changing the Sample Loop .................................................................................... 73
Sample Size .............................................................................................................. 73
Vial Pressurization and Time ................................................................................ 73
Vial Pressurization .......................................................................................... 73
Vial Pressurization Time ................................................................................. 74
Optimizing Carrier Gas Flow ................................................................................. 74
Recommended 68 0/6850 GC Liner ...................................................................... 75
Chapter 8 Running a Sample
Setting Conditions ................................................................................................... 78
Flow Rates ........................................................................................................ 78
Setting the Carrier Gas Flow Rate for the G1883/G12 0 ............................ 80
Setting the Vial Pressurization Gas Pressure for the G1883/G12 0 ....... 81
Setting Carrier and Vial Pressurization Flows for the G128 .................... 81

Contents
iv
Chapter 9 Maintaining the Instrument
Common Replacement Parts and Consumables ................................................85
Fuse Locations ........................................................................................................88
Changing the Sampling Needle ..............................................................................8
Changing the Sample Loop ..................................................................................... 2
Steam Cleaning the Pneumatic System ................................................................. 5
Installing the Transfer Line onto the Volatiles Interface .................................... 6
Aligning the Vial Loader (G128 /G12 0 only) ...................................................... 7
Adjusting the potentiometers ......................................................................... 7
Procedure ..........................................................................................................
Other vial handling adjustments ..................................................................101
Checking carousel adjustment .............................................................................101
Leak Testing: General Information ......................................................................103
Leak Testing a G128 to 68 0 GC Interface ........................................................105
Carrier Gas Flow Path ...................................................................................105
Carrier Flow Path Pressurization Test ........................................................107
Vial Pressurization Gas (Aux) Flow Path ...................................................108
Leak Testing a G12 0/G1883 to GC Interface .....................................................110
Prepare the Sampler ......................................................................................110
Carrier Gas Flow Path ...................................................................................110
Vial Pressurization Flowpath .......................................................................111
Flow Testing the Vent Valve and Associated Flow Path ..................................112
Tightening the PTV Septumless Head Using the Leak Test Procedure ..........113
Chapter 10 Troubleshooting
Chromatography Problems ..................................................................................116
No Peaks .........................................................................................................116
Bad Data (Bad Peaks) ...................................................................................117
Unwanted Peaks Present ..............................................................................11
Vial Handling Problems (G128 /G12 0 only) .....................................................11
Gripper Arm Doesn’t Pick Up Sample Vial .................................................11
Sample Vial Doesn’t Drop Down Into Oven ...............................................120
Vial Not Raised and Lowered in Oven .........................................................121
Vial Not Loaded/Vial Retained Warning ......................................................121

Contents
v
Vial Jam Problems (G128 /G12 0 only) ............................................................. 121
Recovering from vial jam problems ............................................................ 122
Mechanical/Electrical Problems .......................................................................... 122
Instrument Resets Continuously ................................................................. 122
No Power ........................................................................................................ 123
Oven Carousel Won’t Rotate Properly ........................................................ 123
Oven Carousel Won’t Agitate ....................................................................... 123
Sample Tray Doesn’t Stop at Correct Location (G128 /G12 0 only) ...... 124
Sampling Sequence Won’t Start ................................................................... 124
Second Method in Sequence Won’t Start ................................................... 125
Zones Won’t Heat .......................................................................................... 125
Pressures Are Wrong .................................................................................... 126
Chapter 11 Error Messages
Error Message Listing ........................................................................................... 128
Recovery from an Automation Error (G128 /G12 0) ....................................... 133
Glossary ...................................................................................... 135
Index ........................................................................................... 141

Contents
vi

1
About This Manual

About This Manual
Manual Overview
2
About This Manual
The 7694 Headspace Sampler Operating Manual explains how to use the 76 4
Headspace Sampler. It includes all the basic information the user needs to
develop methods, use the sampler to carry out analyses, and maintain and
troubleshoot the sampler.
For site preparation requirements and checkout procedures, see the 7694
Headspace Sampler Site Preparation and Installation Manual.
Manual Overview
This manual contains ten chapters, a glossary, and an index.
Chapter 1: About This Manual provides the purpose of this manual and an
overview of its contents. It identifies the intended reader and lists the
conventions used throughout the manual.
Chapter 2: Introduction to Headspace and to the 7694 Headspace
Sampler provides an overview of headspace theory and practice. It describes
the instrument and its modes of operation.
Chapter 3: The eypad describes the keypad, the functions each key
controls, and how to enter new setpoints for each function.
Chapter 4: Using the Adv Fctn ey describes the advanced functions
controlled by the Adv Fctn key, how to edit setpoints for these functions, and
the displays that accompany each function.
Chapter 5: Preparing a Sample describes the preparation of a sample for
analysis, including filling and sealing the sample vial, loading the sample tray,
and running a checkout sample.
Chapter 6: Entering a Method describes the steps to follow in entering a
method, including changing setpoints, storing and retrieving a method, and
chaining methods.

About This Manual
Intended User
3
Chapter 7: Developing Methods describes the parameter changes that can
affect sensitivity, precision, and accuracy.
Chapter 8: Running a Sample summarizes operation of the headspace
sampler to run a sample.
Chapter 9: Maintaining the Instrument describes maintenance procedures
including changing the sample loop, transfer line, needle, valves, and EPROM.
Chapter 10: Troubleshooting lists the possible causes and solutions for
chromatography problems or instrument failure.
Chapter 11: Error Messages describes the various error messages that
accompany machine failures and the means to correct the failures.
Intended User
This manual is intended for users who understand the basics of gas
chromatography. Although the manual contains some headspace theory, it
primarily provides operating, maintenance, and troubleshooting information
for the 76 4 Headspace Sampler.
Conventions
The following conventions are used in this manual:
1. Braces { } enclose a generic name for which you should substitute specific
information. For example, {setpoint} means you should key in the numeric
value you desire for the setpoint.
2. Text in Bold means that you should press the key by that name.
Be careful how you enter information. For example, the key sequence Adv
Fnct, ., 1, Enter indicates that you should press the Adv Fnct key, the .
key, the 1 key, and then Enter. It does not mean that you should press a
comma (“,”). There is no comma on the sampler’s keypad.
3. Text in Courier indicates the message you will read on the sampler
display.

About This Manual
Conventions
4

2
Introduction to Headspace and to the
7694 Headspace Sampler

6
Introduction to Headspace and to the
7694 Headspace Sampler
This chapter briefly describes the theory and application of headspace
analysis. It describes the parts of the 76 4 Headspace Sampler and its modes of
operation.
Overview of Headspace Analysis
Your new headspace sampler is a tool for introducing volatiles that are
contained in liquid or solid samples into a gas chromatograph. The analytical
technique is called “static headspace gas chromatography.” The term
“headspace” refers to the space above the liquid or solid sample that you place
in a sealed vial. The term “static” means that the volatiles in the headspace of
the vial are at equilibrium with the same compounds in the liquid or solid
sample.
The instrument extracts a reproducible volume of the headspace and injects it
into the carrier gas flowing into the gas chromatograph. Food, packaging,
pharmaceutical products, soil, and water are often tested to see if they meet
quality criteria or regulatory standards. Fragrances and consumer products are
analyzed using headspace in order to understand their composition. Forensics
laboratories use headspace for measuring the percent of ethanol in human
blood to see if a driver is legally intoxicated.
The ease with which a sample forms a gaseous headspace depends on the
sample’s “partition coefficient.” See “Developing Methods” on page 68 for a
more thorough explanation. After a programmed heating time, the headspace
gas is extracted from the vial and injected into a GC for analysis.
There are two means of extracting the headspace gas from the vial—single or
multiple headspace extraction (MHE). With single headspace extraction, only
one sample of gas is taken from each sample vial. Single headspace extraction
is the standard method. It is used for samples that are readily volatile or for

Introduction to Headspace and to the 7694 Headspace Sampler
The 7694 Headspace Sampler
7
which there are no matrix effects. Quantitative analysis can be performed by
using suitable internal or external standards.
MHE is available only in models G128 and G12 0. MHE is used for headspace
samples for which no calibration standard can be prepared easily (for example,
solid samples) or for highly volatile compounds in liquids, where the method of
standard addition is difficult because of losses due to evaporation. MHE takes
several headspace samples from each vial. With each extraction, the
concentration of the volatile compound in both the gas phase and the sample
becomes smaller, although the ratio remains constant. The logs of the peak
areas versus the extraction number are plotted to obtain quantitative data
about the compound of interest.
MHE is often used as a calibration tool. Once the peak area versus the
concentration is established for a given sample matrix, quantitative
measurements of samples with a similar matrix can be carried out using a
single extraction.
The 7694 Headspace Sampler
The 76 4 Headspace Sampler provides an automated method to run up to
44 samples consecutively without operator attention. The sampler’s
microprocessor optimizes the time spent for each run according to the values
programmed in by the operator. Up to four different methods can be stored and
used to analyze a series of samples.
Models G128 and G12 0 can also be used for multiple HS extraction using
multiple septum punctures, with up to 10 extractions per sample.
You can also automate optimization routines. The unit is made up of the
following components:
Oven (G1289/G1290)
The oven contains a circular aluminum sample carousel that can hold up to six
10- or 20 ml sample vials. A resistance band heater is used for heating. A

Introduction to Headspace and to the 7694 Headspace Sampler
The 7694 Headspace Sampler
8
motor–driven fan in the center of the carousel circulates the air to maintain
constant and uniform temperature. The carousel can be shaken to help
components elute into the headspace quicker. Mechanical rods move vials up
for removal by a robotic arm or for sampling.
Adapters (part no. 301–017–HSP) are required in the carousel when 10 ml vials
are used.
Heated Zones (G1883)
There are three heated zones. They are the vial oven, the loop, and the transfer
line. The vial oven is where the vial is heated during thermal and chemical
stabilization. Setpoint temperature range is between 40 and 200°C. At this
point, the needle has not pierced the septum. The loop zone is controlling the
temperature of the upper chamber, the valve, and the sample loop. The
setpoint range of the loop is between 50 and 200°C. It is recommended that the
loop temperature is kept 15°C higher than the vial temperature for most
operations.
Figure 1. Overview of the 7694 Headspace Sampler (from front of instrument)
G1289/G1290 G1883
**
Keypad and display
Vial pressurization control*
Pneumatic
compartment
Vial transport arm
Vial tray
Vial pressurization control
Carrier gas flow control
Carrier gas flow control
* Standalone unit only

Introduction to Headspace and to the 7694 Headspace Sampler
The 7694 Headspace Sampler
9
Figure 2. Overview of the 7694 Headspace Sampler (from back of instrument)
Vial Tray (G1289/G1290)
The 44–sample vial tray is located on top of the unit to the left of the oven. The
tray is constructed of a flexible belt with dividers for each vial compartment.
Tray rotation is controlled via the keypad to assist filling the tray with
headspace vials. The tray can move forward and backward. When you use the
keypad to move the tray from position 1 to 44 (or from 44 to 1) the tray will
rotate completely. Adapters (part no. 300–305–HSP) are needed in the sample
tray when 10 ml vials are used.
Vial Transport Arm (G1289/G1290)
A robotic arm moves samples from the vial tray into the oven and back. Vials
are lifted from the tray, carried across the unit until centered above a port in
the oven, and then dropped into place. The rail supporting the robotic arm
swings away to allow access to the oven. Use the switch on the back of the
support rail to set the arm for either 10- or 20 ml vials.
G1289/G1290 G1883
Transfer line
Carrier gas in
Power switch
= On
O = Off
Vial pressurization
in
Transfer line
Vial
pressurization in

Introduction to Headspace and to the 7694 Headspace Sampler
The 7694 Headspace Sampler
10
Sampling System
The basic components include a 316–stainless–steel single–hole (side port)
concentric vial–sampling needle or probe with an internal diameter of 0.5 mm,
316–SS six–port valve, nickel valve sample loop, set of two miniature solenoid
valves, and nickel tubing. You can program the system’s temperature up to
200°C.
Also available is a fused silica-lined stainless steel sampling path (Accessory
G1286A).
Transfer Line
This line connects the headspace sampler with the GC. Two types are
available: standard nickel and fused silica–lined stainless steel. The line is
heated to a maximum temperature of 220°C. There is a removable needle for
easy interfacing through GC inlet septa.
Table 1. Transfer Lines
Keypad and Display
The headspace sampler has a 25–key elastomeric keypad. The display is a
single–line 20–character LED dot matrix design. All functions of the sampler
are controlled from the keypad with the exception of EPC, which is controlled
from the GC or ChemStation.
Material Length, cm Part umber Comment
Nickel 68 301–011–HSP
Nickel 82 301–152–HSP Standard transfer line
Fused silica-lined
stainless steel
82 301–211–HSP For applications requiring a
highly inert non–metal flow
path

Introduction to Headspace and to the 7694 Headspace Sampler
The 7694 Headspace Sampler
11
Pneumatics
The G12 0 and G1883 headspace samplers use two flow paths: GC carrier gas
flow and flow for vial pressurization. You control the GC carrier gas flow using
a manual flow controller and the vial pressurization using a manual pressure
regulator.
The G128 samplers uses the same gas streams, but all flow and pressure
control is provided by the 68 0 GC.
In all models, two 1/8–inch Swagelok® bulkhead fittings are provided at the
rear of the pneumatic compartment for connecting lines for vial pressure and
carrier gas.

Introduction to Headspace and to the 7694 Headspace Sampler
The 7694 Headspace Sampler
12
Figure 3. Pneumatic system for the 7694 Headspace Sampler
Model 1289 units do not have
pressure regulators or flow controllers.
Pressure regulator-standalone units only
I
Flow controller-standalone units only
Stainless steel tubing
Solenoid valves
Transfer line
Sample loop
Six port
injection
valve
Vial sampling
needle
Stainless
steel tubing