Waters 432 Operator's Manual
Waters 432 Conductivity
t
Detector
Operator’s Guide
34 Maple Stree
Milford, MA 01757
71500043202, Revision A
NOTICE
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 a c cu rate at th e time o f p u blication. In no event shall Water s
Corporation be liable for incidental or consequential damages in connection with or arising
from the use of this document.
1994–2003 WATERS CORPORATION. PRINTED IN THE UNITED STATES OF
AMERICA. ALL RIGHTS RESERVED. THIS DOCUMEBNT OR PARTS THEREOF MAY
NOT BE REPRODUCED IN ANY FORM WITHOUT THE WRITTEN PERMISSION OF
THE PUBLISHER.
Alliance, Millennium, and Waters are registered trademarks, and Empower, LAC/E,
PowerLine, SAT/IN, Sep-Pak, UltraWISP, and WISP are trademarks of Waters
Corporation.
All other trademarks or registered trademarks are the sole property of their respective
owners.
When you use the instrument, follow generally accepted procedures for quality
P
Note:
control and methods development.
If you observe a change in the retention of a particular compound, in the resolution
between two compounds, or in peak shape, immediately determine the reason for the
changes. Until you determine the cause of a change, do not rely on the separation results.
The Installation Category (Overvoltage Category) for this instrument is Level II. The
Note:
Level II Category pertains to equipment that receives its electrical power from a local level,
such as an electrical wall outlet.
STO
Atención:
responsible for compliance could void the user’s authority to operate the equipment.
Importan t :
par l’autorité responsable de la conformité à la réglementation peut annuler le droit de
l’utilisateur à exploiter l’équipement.
Achtun g :
ausdrückliche Genehmigung der für die ordnungsgemäße Fun ktion stüchtigkeit
verantwortlichen Personen kann zum Entzug der Bedienungsbefugnis des Systems
führen.
Avvertenza:
espressamente approvate da un ente responsabile per la conformità annulleranno
l’autorità dell’utente ad operare l’apparecchiatura.
Atención:
expresamente aprobado por la parte responsable del cumplimiento puede anular la
autorización del usuario para utilizar el equip o .
Changes or modifications to this unit not expressly approved by the party
Toute modification sur cette unité n’ayant pas été expressément approuvée
Jedwede Änderungen oder Modifikationen an dem Gerät ohne die
eventuali modifiche o alterazioni apportate a questa unità e non
cualquier cambio o modificación efectuado en esta unidad que no haya sido
Caution:
Use caution when working with any polymer tubing under pressure:
• Always wear ey e protection when near pressurized polymer tubing.
• Extinguish all nearby flames.
• Do not use Tefzel tubing that has been severely stressed or kinked.
• Do not use Tefzel tubing with tetrahydrofuran (THF) or concentrated nitric or
sulfuric ac id s.
• Be aware that methylene chlor ide and dimethyl sulfoxide cause Tefzel tubing to
swell, which greatly reduces the rupture pressure of the tubing.
Attention :
Soyez très prudent en travaillant avec des tuyaux de polymères sous
pression :
• Portez toujours des lunettes de protection quand vous vous trouvez à proximité de
tuyaux de polymères.
• Eteignez toutes les flammes se trouvant à proximité.
• N'utilisez pas de tuyau de Tefzel fortement abîmé ou déformé.
• N'utilisez pas de tuyau de Tefzel avec de l'acide sulfurique ou nitrique, ou du
tétrahydrofurane (THF).
• Sachez que le chlorure de méthylène et le sulfoxyde de diméthyle peuvent
provoquer le gonflement des tuyaux de Tefzel, diminuant ainsi for tem ent leur
pression de rupture.
Vorsicht:
Bei der Arbeit mit Polymerschläuchen unter Druck ist besondere Vorsicht
angebracht:
• In der Nähe von unter Druck stehenden Polymerschläuchen stets Schutzbrille
tragen.
• Alle offenen Flammen in der Nähe löschen.
• Keine Tefzel-Schläuche verwenden, die stark geknickt oder überbeansprucht sind.
• Tefzel-Schläuche nicht für Tetrahydrofuran (THF) oder konzentrierte Salpeter- oder
Schwefelsäure verwenden.
• Durch Methylenchlorid und Dimethylsulfoxid können Tefzel-Schläuche quel len;
dadurch wird der Berstdruck des Schlauches erheblich reduziert.
Precauzio ne :
prestare attenzione durante le operazioni con i tubi di polimero sotto
pressione:
• Indossare sempre occhiali da lavoro protettivi nei pressi di tubi di polimero
pressurizzati.
• Estinguere ogni fonte di ignizione circostante.
• Non utilizzare tubi Tefzel soggetti a sollecitazioni eccessive o incurvati.
• Non utilizzare tubi Tefzel contenenti tetraidrofurano (THF) o acido solforico o nitrico
concentrato.
• Tenere presente che il cloruro di metilene e il dimetilsolfossido provocano
rigonfiamento nei tubi Tefzel, che riducono not evolmente il limite di pressione di
rottura dei tubi stessi.
Advertencia:
manipular con precaución los tubos de polímero bajo presión:
• Protegerse siempre los ojos en las proximidades de tubos de polímero bajo
presión.
• Apagar todas las llamas que estén a proximidad.
• No utilizar tubos Tefzel que hayan sufrido tensiones extremas o hayan sido
doblados.
• No utilizar tubos Tefzel con tetrahidrofurano (THF) o ácidos nítrico o sulfúrico
concentrados.
• No olvidar que el cloruro de metileno y el óxido de azufre dimetilo dilatan los tubos
Tefzel, lo que reduce en gran medida la presión de ruptura de los tubos.
Caution:
The user shall be made aware that if the equipment is used in a manner not
specified by the manufacturer, the protection provided by the equipment may be impaired.
Attention :
L’utilisateur doit être inform é que si le mat ériel est utilisé d’une façon non
spécifiée par le fabricant, la protection assurée par le matériel risque d’être défectueuses.
Vorsicht:
Der Benutzer wird darauf aufmerksam gemacht, dass bei unsachgemäßer
Verwenddung des Gerätes unter Umständen nicht ordnungs gem äß funktionieren.
Precau zion e :
l’utente deve essere al corrente del fatto che, se l’apparecchiatura viene
usta in un modo specificato dal produttore, la protezione fornita dall’apparecchiatura
potrà essere invalidata.
Adver tenc ia:
el usuario deberá saber que si el equipo se utiliza de forma distinta a la
especificada por el fabricante, las medidas de protección del equipo podrían ser
insuficientes.
Caution:
rating.
To protect against fire hazard, replace fuses with those of the same type and
Attention :
Remplacez toujours les fusibles par d’autres du même type et de la même
puissance afin d’éviter tout risque d’incendie.
Vorsicht:
Zum Schutz gegen Feuergefahr die Sicherungen nur mit Sicherungen des
gleichen Typs und Nennwertes ersetzen.
Precauzio ne :
per una buona protezione contro i rischi di incendio, sostituire i fusibili con
altri dello stesso tipo e amperaggio.
Advertencia:
sustituy a l o s fusibles por o tros del mismo tipo y características para evitar
el riesgo de incendio.
Caution:
To avoid possible electrical shock, disconnect the power cord before servicing
the instrument.
Attent i on :
Afin d’éviter toute possibilité de commotion électrique, débranchez le cordon
d’alimentation de la prise avant d’effectuer la maintenance de l’instrument.
Vorsicht:
Zur V ermeidung von Stromschlägen sollte das Gerät vor der Wartung vom
Netz getrennt werden.
Precauzio ne :
per evitare il rischio di scossa elettrica, scollegare il cavo di alimentazione
prima di svolgere la manutenzione dello strumento.
Precaució n:
para evitar descargas eléctricas, desenchufe el cable de alimentación del
instrumento antes de realizar cualquier reparación.
Commonly Used Symbols
Direct current
Courant continu
Gleichstrom
Corrente continua
Corriente continua
Alternating current
Courant alternatif
Wechselstrom
Corrente alternata
Corriente alterna
Protective conductor terminal
Borne du conducteur de protection
Schutzleiteranschluss
Ter m ina le di conduttore con protezione
Borne del conductor de tierra
Commonly Used Symbols (Continued )
Frame or chassis terminal
Borne du cadre ou du châssis
Rahmen- oder Chassisanschluss
Ter m ina le di str uttura o telaio
Borne de la estructura o del chasis
Caution or refer to manual
Attention ou reportez-vous au guide
Vorsicht, oder lesen Sie das Handbuch
Prestare attenzione o fare riferimento alla guida
Actúe con precaución o consulte la guía
Caution, hot surface or high temperature
Attention, surface chaude ou température élevée
Vorsicht, heiße Oberfläche oder hohe Temperatur
Precauzione, superficie calda o elevata temperatura
Precaución, superficie caliente o temperatura elevada
Commonly Used Symbols (Continued )
Caution, risk of electric shock (high voltage)
Attention, risque de commot ion électri que (haut e tension )
Vorsicht, Elektroschockgefahr (Hochspannung)
Precauzione, rischio di scossa elettrica (alta tensione)
Precaución, peligro de descarga eléctrica (alta tensión)
Caution, risk of needle-stick puncture
Attention, risques de perforation de la taille d’une aiguille
Vorsicht, Gefahr einer Spritzenpunktierung
Precauzione, rischio di puntura con ago
Precaución, riesgo de punción con aguja
Caution, ultraviolet light
UV
Attention, rayonnement ultrviolet
Vorsicht, Ultr a violettes Licht
Precauzione, luce ultravioletta
Precaución, emisiones de luz ultravioleta
Commonly Used Symbols (Continued )
1
0
Fuse
Fusible
Sicherung
Fusibile
Fusible
Electrical power on
Sous tension
Netzschalter ein
Alimentazione elettrica attivata
Alimentación eléctrica conectada
Electrical power off
Hors tension
Netzschalter aus
Alimentazione elettrica disat tivata
Alimentación eléctrica desconectada
432 Conductivity Detector Information
Intended Use
The Waters® 432 Conductivity Detector can be used for in-vitro diagnostic testing to
analyze many compounds, including diagnostic indicators and therapeutically monitored
compounds. When you de velop methods, follow the “Protocol for the Adoption of
Analytical Methods in the Clinical Chemistry Laborator y,” American Journal of Medical
Tech nol ogy, 44, 1, pages 30–37 (1978). This protocol covers good operating procedures
and techniques necessary to validate system and method performance.
Biological Hazard
When you analyze physiological fluids, take all necessary precaut ions and treat all
specimens as potentially infectious. Precautions are outlined in “CDC Guidelines on
Specimen Handling,” CDC – NIH Manual, 1984.
Calibration
Follow acceptable methods of calibration with pure standards to calibrate methods. Use a
minimum of five standards to generate a standard curve. The concentration range should
cover the entire range of quality-control samples, typical specimens, and atypical
specimens.
Quality Control
Routinely run three quality-control samples. Quality-control samples should represent
subnormal, nor m al, and above-norm al levels of a compound. Ensure that quality-control
sample results are within an acceptable range, and ev aluate precision from day to day and
run to run. Data collected when quality-control samples are out of range may not be valid.
Do not report this data until you ensure that chromatographic system performance is
acceptable.
Table of Contents
Preface ....................................................................................... 23
Chapter 1
Introduction .................. ............................. ............................. .......... 26
Chapter 2
Installing the Detector ...................................................................... 30
2.1 Selecting the Installation Site................................................ 30
2.2 Unpacking and Inspection..................................................... 31
2.3 AC Power Connection ........................................................... 32
2.4 I/O Signal Connections......................................................... 35
2.4.1 I/O Signal Desc ri pt ions ....... ..... .... ..... ................... ..... . 35
2.4.2 Powe rLine Controller Connections ............................ 37
2.4.3 Empower and Millennium
32
Connections .................. 39
2.4.4 Data Module Connections ......................................... 44
2.4.5 Chart Recorder Connections..................................... 45
2.4.6 Chart Marker Input Connections................................ 45
2.4.7 Auto Zero Input Connections..................................... 46
2.4.8 Alliance Separatio ns Mo dule Connec tion s ............... . 46
2.5 Making Fluidic Connections.................................................. 48
2.6 Passivating the System......................................................... 53
2.7 Verifying the Detector............................................................ 54
Table of Contents 15
Chapter 3
Operating the Detector .................................................................... 56
3.1 Controls and Indicators......................................................... 56
3.2 Startup and Shutdown .......................................................... 61
3.3 Operating Recommendations ............................................... 62
Chapter 4
Performing Ion Analysis ................................................................... 64
4.1 Fundamental Considerations................................................ 64
4.2 Configuring the System......................................................... 68
4.3 Eluents for Ion Analysis......................................................... 69
4.3.1 Preparing Anion Eluent....... ................... ..... ..... .... ...... 70
4.3.2 Preparing Cation Eluent .......... .... ..... ..... ..... ..... .......... 70
4.4 Standards for Ion Analysis .................................................... 70
4.4.1 Preparing Anion Standa rds ......... ..... ................... ..... . 71
4.4.2 Injecting Anion Standards.......................................... 72
4.4.3 Preparing Cation Standard s ............. ..... ................... . 74
4.4.4 Injecting Cati on Stan dar ds........... ..... ..... ..... ..... .......... 76
Chapter 5
Maintenance .................................................................................... 78
5.1 Routine Maintenance............................................................ 78
5.1.1 Replacing the Fuse.................................................... 78
5.1.2 Maintaining the Flow Cell........................................... 79
5.2 Cleaning the Detector Exterior.............................................. 82
5.3 Troubleshooting..................................................................... 82
Table of Contents 16
Appendix A
Specifications ................................................................................... 87
Appendix B
Spare Parts......... ..... ..... ..... ..... .... ..... ................... ..... ..... ..... ..... .......... 90
Appendix C
Ion Chromatography Methods .......................................................... 91
C.1 General-Purpose Anion Analysis Using Conductivity
and UV Detection ................................................................ 91
C.1.1 Prepa rin g Eluent ...... ..... ..... ..... .... .................... .... ..... . 93
C.1.2 Prepa rin g Stand ard s .......... ..... ................... ..... .... ..... . 93
C.1.3 Preparing a Sample .................................................. 93
C.1.4 Empower Data Processing Method........................... 94
C.1.5 Method Valid atio n .............. ..... .... ..... ..... ..... ............... 95
C.1.6 Method Linea rity.. ..... ..... ..... ................... ..... ..... .... ..... . 95
C.1.7 Quantita tion Prec ision... ..... ..... .... ..... ..... ..... ............... 97
C.1.8 Method Detection Limits............................................ 97
C.1.9 Quantita tion Accu racy... ..... ..... .... ..... ................... ..... . 98
C.1.10 Analyte Recovery.................................................... 99
C.1.11 Example of Use..................................................... 100
C.1.12 Using Direct UV Detection .................................... 100
C.1.13 Preparing Lithium Borate/Gluconate 50X
Stock Concentrate................................................... 102
C.1.14 Preparing Lithium Borate/Gluconate Eluent.......... 102
Table of Contents 17
C.2 Alkali and Alkaline Earth Cations, Ammonium,
and Amines........................................................................ 103
C.2.1 Prepa rin g Elu ent .................... .... ..... ................... .... 104
C.2.2 Prepa rin g Stand ard s .......... ..... ................... ..... .... .... 104
C.2.3 Preparing a Sample ................................................ 105
C.2.4 Empower Data Processing Method......................... 105
C.2.5 Method Detection Limits.......................................... 106
C.2.6 Examples of Use..................................................... 107
C.2.7 Preparing Stock Reagent........................................ 108
Appendix D
Validation Support .......................................................................... 109
Index ..................................................................................... 111
Table of Contents 18
List of Figures
1-1 Waters 432 Conductivity Detector.................................................26
1-2 Flow Cell Schematic ......................................................................28
2-1 Rear Panel..................................................................................... 33
2-2 Changing the Voltage Setting........................................................34
2-3 I/O Terminal Strip...........................................................................36
2-4 IEEE-488 Address Switch..............................................................38
2-5 Bus SAT/IN Module (Front Panel).................................................. 40
2-6 Bus SAT/IN to Bus LAC/E Connections.........................................42
2-7 Bus SAT/IN to 432 Detector Connections...................................... 43
2-8 Alliance Separations Module Connections to the 432
Detector Auto-Zero on Inject..........................................................47
2-9 Alliance Separations Module Connections to the 432
Detector Chart Mark on Inject........................................................48
2-10 Fluid Connections.......................................................................... 49
2-11 Cutting Po lymeric Tubing...............................................................50
2-12 Ferrule and Compression Screw Assembly...................................51
2-13 Pulse Dampener............................................................................ 53
3-1 Front Panel ....................................................................................56
4-1 Soda Lime Tube.............................................................................67
4-2 System Configuration for Ion Analysis...........................................68
4-3 Chromatogram of a 7-Anion Standard........................................... 74
4-4 Chromatogram of an 8-Cation Standard........................................77
5-1 Installing Operating Voltage Fuses................................................79
5-2 Flow Cell Assembly....................................................................... 81
C-1 Common Anion Standards ............................................................92
List of Figures 19
C-2 Calibration Curves for Chloride, Fluoride, and Bromide ............... 95
C-3 Calibration Curves for Nitrite and Nitrate ...................................... 96
C-4 Calibration Curves for Sulfate and Phosphate ..............................96
C-5 100-mL Injection ...........................................................................97
C-6 Typical Drinking Water, No Dilution Required ............................100
C-7 Direct UV Detection ....................................................................101
C-8 100-ppb Anion Standard .............................................................101
C-9 1-ppm Standard .......................................................................... 103
C-10 25-ppb Cation Standard ..............................................................106
C-11 Typical Drinking Water, No Dilution Required ............................107
C-12 Typical Municipal Wastewater, Diluted 1:50, Overlay
of Duplicate Injections.................................................................. 107
List of Figures 20
List of Tables
1-1 Limiting Equivalent Conductance of Ions in Water at 25 °C .........29
2-1 Power Cord Wire Identification .....................................................33
2-2 Nominal Operating Voltage...................................................... 34
2-3 I/O Signal Descriptions ........................................................... 36
2-4 IEEE-488 DIP Switch Setting.................................................. 38
2-5 Bus SAT/IN Cable Connections............................................... 44
2-6 Data Module Signal Cable Connections .................................. 44
2-7 Data Module Chart Mark Cable Connections........................... 45
2-8 Chart Recorder Cable Connections......................................... 45
2-9 Autosampler Chart Mark Cable Connections........................... 46
2-10 Autosampler Auto Zero Cable Connections............................. 46
2-11 Connections for Generating Auto-Zero on Inject...................... 47
2-12 Connections for Generating Chart Mark on Inject.................... 48
3-1 Key Descriptions ...........................................................................58
3-2 Setting the Beep Function....................................................... 60
4-1 Shelf-Life of Standards .................................................................71
4-2 Salts for Anion Standard Concentrates.................................... 72
4-3 Anion Concentrate Dilutions.................................................... 72
4-4 Salts for Cation Standard Concentrates .................................. 75
4-5 Cation Concentrate Dilutions ................................................... 75
5-1 Troubleshooting Guide ..................................................................85
A-1 Operational Specifications ............................................................87
A-2 Mechanical Specifications............................................................ 87
A-4 Electrical Specifications................................................................ 88
A-3 Environmental Specifications........................................................ 88
List of Tables 21
A-5 Communications........................................................................... 89
B-1 Spare Parts ...................................................................................90
C-1 Required Instru ment ation ...................................................... .......91
C-1 Analysis Conditions ......................................................................92
C-2 IC Processing Method Using Peak Apex for Retention Time....... 94
C-3 Method Validation......................................................................... 95
C-4 Quantitation Precision................................................................... 97
C-5 Quantitation Accuracy................................................................... 98
C-6 Analyte Recovery.......................................................................... 99
C-1 Required Instru ment ation ...................................................... .....103
C-2 Analysis Conditions.................................................................... 104
C-3 IC Processing Method Using Peak Apex for Retention Time..... 105
List of Tables 22
Preface
The Waters 432 Conductivity Detector Operator’s Guide details the procedures for
unpacking, installing, operating, maint ain ing, and troubleshooting the 432 Conductivity
Detector. It also includes appendixes listing specifications and spare parts and describing
validation support.
This guide is intended for use by personnel who need to install, operate, maintain, or
troubleshoot the 432 Detector. This guide assum es an understandi ng of the princip les of
chromatography.
Organization
This guide contains the following:
Chapter 1
Chapter 2
electrical connections.
Chapter 3
general operating instructions.
Chapter 4
for anion and cation analysis.
Chapter 5
tables to aid in problem diagnosis.
Appendix A
Detector.
Appendix B
Appendix C
Appendix D
support .
describes the features and method of operation of the 432 Detector.
describes the procedures for installing the 432 Detector and making fluid and
describes the controls and indicators of the 432 Detector, and provides
describes the system configuration, eluents, and standards recommended
describes simple maintenance procedures and provides troubleshooting
describes the operational specifications and requirements of the 432
lists the recommended spare parts for the 432 Detector.
describes ion chromatography methods.
describes the recommended validation protocols and Waters® validation
Related Documentation
Waters Licenses, Warranties, and Support: Provides software license and warranty
information, describes training and extended support, and tells how Waters handles
shipments, damages, claims, and returns.
23
Documentation on the Web
Related product information and documentation can be found on the W orld Wide Web .
Our address is http://www.waters.com
.
Related Adobe Acrobat Reader Documentation
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printing electronic documentation from Adobe Acro bat Reader.
Printing This Electronic Docu men t
Adobe Acrobat Reader lets you easily print pages, page ranges, or the entire document by
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PostScript
resolution.
®
printer driver for your printer. Ideally, use a printer that supports 600 dpi print
Documentation Conventions
The following conventions can be used in this guide:
Convention Usage
Purple
Italic Italic indicates information that you supply such as variables. It also
Courier
Courier Bold
Underlined Blue I ndi cates hypert ext cross-references to a specific chapter, section,
Keys T he word key refers to a computer key on the keypad or keyboard.
Purple text indicates user action such as keys to press, menu selections, and commands. For example, “Click Next to go to the next
page.”
indicates emphasis and document titles. For example, “Replace
file_name with the actual name of your file.”
Courier indicates examples of source code and system output. For
example, “The SVRMGR> prompt appears.”
Courier bold indicates characters that you type or ke ys you press in
examples of source code. For example, “At the LSNRCTL> prompt,
enter set password oracle to access Oracle.”
subsection, or sidehead. Clicking this topic using the hand symbol
brings you to this topic within the document. Right-clicking and
selecting Go Back from the short c ut menu returns you to the origi-
nating topic. For example, “The detector’s I/O signals are described
in Section 2.4,
Screen keys ref er to the ke ys on the instrument located immediately
below the screen. For example, “The A/B screen key on the 2414
Detector displays the selected channel.”
I/O Signal Connections.”
24
P
Convention Usage
… Three periods indicate that more of the same type of item can
optionally follow. For example, “You can store filename1, filename2,
… in each folder.”
>
Notes
Notes call out information that is helpful to the operator. For example:
Record your result before you proceed to the next step.
Note:
Attentions
Attentions provide information about preventing damage to the system or equipment. For
example:
A right arrow between menu options indicates you should choose
each option in sequence. For example, “Select File > Exit” means
you should select File from the menu bar, then select Exit from the
File menu.
Attention:
STO
Cautions
window.
Cautions provide information essential to the safety of the operator. For example:
Caution:
replacement or adjustment.
Caution:
performing maintenance procedures.
Caution:
when operating the system.
To avoid damaging the detector flow cell, do not touch the flow cell
To avoid burns, turn off the lamp at least 30 minutes before removing it for
To avoid electrical shock and injury , unplug the power cord before
To avoid chemical or electrical hazards, observe safe laboratory practices
25
Chapter 1 Introduction
Features
The Waters® 432 Conductivity Detector (Figure 1-1) is specifically designed to be
integrated into chromatographic systems. The following features contribute to its
performance in measuring the conductivity of column eluents:
• Unique 5-electrode flow cell design
• Heat exchanger and a built-in automatic temperature control system for stable
operation
• Auto baseline/auto zero
• External recorder/integrator and chart mark connections
• Three time constant selections
• “Leak-detected” alarm signal
W
aters 432
Conductivity Detector
1
TP01268
IN
OUT
Figure 1-1 Waters 432 Conductivity Detector
26
Method of Operation
This section discusses the method of operation of the 432 Detector. Additional descriptive
information appears in these sections:
• Section 2.4.1,
• Section 3.1, Controls and Indicators
• Appendix A, Specifications
Measurement Technique
The 432 Detector responds to all ions present in the flow cell, since all ions in solution
conduct electricity. This allows the 432 Detector to detect a wide variety of sample ions.
The 432 Detector eliminates the eluent’s contribution to conductivity with an electronic
technique called baseline suppression. The detector measures the eluent conductivity and
assigns it a value of zero. Thus, any sample ions appear as positive or negative
measurements, relative to the baseline.
The temperature of an ionic solution affects the conductivity of the ions. Generally, a
solution’s conductivity rises about 2% for every degree Celsius of temperature increase.
The special flow cell heater in the 432 Detector minimizes the effect of ambient
temperature fluctuations on measurement accuracy .
Flow Cell Design
The flow cell in the 432 Detector contains five electrodes connected in a measuring circuit:
two reference electrodes, two detection electrodes, and a guard electrode that provides a
local electrical “ground” (Figure 1-2
set temperature, and then flows through the cell, directly contacting the electrodes. The
5-electrode design permits measurem ent of conduct ivity to be made with a very low
current at the detection electrodes. The low current employed eliminates impedance and
other problems associated with simpler designs, and results in a stable baseline and an
extended range of linearity .
I/O Signal Descriptions
). Column eluent flows through the heater to attain the
1
Introduction 27
1
k
G
TP01271
Ion Detection Theory
1= Reference Electrodes
2= Detection Electrodes
3
Figure 1-2 Flow Cell Schematic
2
3= Guard Electrode
Flow Cell Bloc
(heated)
Fluid Outlet
1
The conductance of a solution of known concentration can be calculated using the
following equation:
λC
----------
=
G = measured conductance of the solution, in Siemens
(1 S = ohm
C = concentration in equivalents per 1000 cm
K = length/area of cell (the cell constant)
λ = equivalent conductance in S cm
Table 1-1 lists the equivalent conductances of some common ions.1 Concentrations above
−5
10
to 10−3 N, generally exhibit decreased equivalent conductance due to interionic
effects.
−1
)
10
3–
3
equiv
−1
2
28
Table 1-1 Limiting Equivalent Conductance of Ions in Water at 25 °C
Cations
+
H
+
Li
+
Na
+
K
+
Rb
+
Ag
+
NH
4
(CH3)2NH
2+
Hg
2+
Mg
2+
Ca
2+
Ba
2+
Cu
2+
Zn
3+
La
3+
Ce
l
+
349.8 OH
38.6 F
50.1 Cl
73.5 Br
77.8 I
61.9 NO3
73.3 ClO
+
2
51.8 ClO
53.0 IO
−
−
−
−
4
Anions
−
−
−
3
−
4
−
198.6
55.4
76.4
78.1
76.8
71.5
64.6
67.4
54.5
λ
—
1
53.1 Formate 54.6
59.5 Acetate 40.9
63.6 Benzoate 32.4
2
53.6 SO
52.8 CO
69.7 Fe(CN)
−
4
2
−
3
4
−
6
80.0
69.3
111.0
69.8
1. Henry H. Bauer et al., eds. “Instrumental Analysis,” Allyn and Bacon, Boston (1978), p. 115. Reprinted
with permission from the publisher.
Introduction 29
Chapter 2 Installing the Detector
This chapter guides you through the following steps in preparing the 432 Detector for
operation in a chromatographic system:
• Selecting an installation site that satisfies the detector’ s power and environmental
requirements
• Unpacking and inspecting the 432 Detector and accompanying items
• Connecting the detector to your AC power supply
• Connecting the detector electrically to the other components of your chromatographic
system
• Connecting the detector inlet to the column and the detector outlet to a waste
receptacle (and, if required, installing the pulse dampener)
• Passivating the detector and other post-column fluid path componen ts
After you have successfully completed this chapter, familiarize yourself with the
information in Section 3.1,
detector, perform the startup procedure described in Section 3.2,
Controls and Indicators. When you are ready to operate the
2.1 Selecting the Installation Site
Operating Environment
The 432 Detector operates in any standard laboratory environment that provides suitable
electrical power and remains within the following ranges:
• Temperatu re: 5 to 35 °C (40 to 95 °F)
• Humidity: 20 to 80%, noncondensing
Install the instrument in a clean area that is free from exposure to:
2
Startup and Shutdown.
• Temperature or humidity extremes, which can be found near direct sunlight, heat
registers, and air conditioning vents
• Strong electromagnetic radiation, such as from large motors or arcing contacts
• Appreciable shock or vibration
Selecting the Installation Site 30
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