Waters 2410 Operator's Manual

Waters 2410

Differential Refractometer

Operator’s Guide

34 Maple Street

Milford, MA 01757

71500241002, Revision 3

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 guide 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 the use of this guide.

2001 WATERS CORPORATION. PRINTED IN THE UNITED STATES OF AMERICA.



Millennium® PIC and Waters are registered trademarks, and busLAC/E and PowerStation are trademarks of Waters Corporation.

Micromass is a registered trademark and MassLynx is a trademark of Micromass Ltd. All other trademarks or registered trademarks are the sole property of their respective owners.

Note

: When you use the instrument, follow generally accepted procedures for quality

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 take steps to determine the reason for the changes. Until you determine the cause of a change, do not rely upon the results of the separations.

Note:

The installation category (Overvoltage Category) for this instrument is Level II. The Level II category pertains to equipment that receives its electrical power from a local lev el, such as an electrical wall outlet.

STOP

Attention:

responsible for compliance could void the user’s authority to operate the equipment.

Important:

par l’autorité résponsable de la conformité à la réglementation peut annuler de droit de l’utilisateur à exploiter l’équipement.

Achtung

ausdrückliche Genehmigung der für die ordnungsgemäße Funktionstüchtigkeit 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 de la que goza el usario para utizar el equipo.

Changes or modiﬁcations to this unit not expressly approved by the party

Toute modeﬁcation sur cette unité n’ayant pas été expressément approuvée

: Jedewede Änderungen oder Modiﬁkationen an dem Gerät ohne die

eventuali modiﬁche o alterazioni apportate a questa unità e non

: cualquier cambio o modiﬁcación realizado a esta unidad que no haya sido

Caution:

Use caution when working with any polymer tubing under pressure:

• Always wear eye 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 acids.

• Be aware that methylene chloride and dimethyl sulfoxide cause Tefzel tubing to swell, which greatly reduces the rupture pressure of the tubing.

Attention

pression:

Vorsicht

angebracht:

: soyez très prudent en travaillant avec des tuyaux de polymères sous

• 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 (THT).

• Sachez que le chlorure de méthylène et le sulfoxyde de diméthyle peuvent provoquer le gonﬂement des tuyaux de Tefzel, diminuant ainsi fortement leur pression de rupture.

: Bei der Arbeit mit Polymerschläuchen unter Druck ist besondere Vorsicht

• 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 Salpeteroder Schwefelsäure verwenden.

• Durch Methylenchlorid und Dimethylsulfoxid können Tefzel-Schläuche quellen; dadurch wird der Berstdruck des Schlauches erheblich reduziert.

Precauzione

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 notevolmente il limite di pressione di rottura dei tubi stessi.

: prestare attenzione durante le operazioni con i tubi di polimero sotto

Advertencia:

• Protegerse siempre los ojos a proximidad de tubos de polimero 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 o ácidos nítrico o sulfúrico concentrados.

• No olvidar que el cloruro de metileno y el óxido de azufre dimetilo inﬂan los tubos Tefzel lo que reduce en gran medida la presión de ruptura de los tubos.

manipular con precaución los tubos de polimero bajo presión:

Caution:

speciﬁed by the manufacturer, the protection provided by the equipment may be impaired.

The user shall be made aware that if the equipment is used in a manner not

Attention:

spéciﬁée par le fabricant, la protection assurée par le matériel risque d’être défectueuses.

Vorsicht:

Verwenddung des Gerätes unter Umständen nicht ordnungsgemäß funktionieren.

Precauzione:

usta in un modo speciﬁcato dal produttore, la protezione fornita dall’apparecchiatura potrà essere invalidata.

Advertencia:

especiﬁcada por el fabricante, las medidas de protección del equipo podrían ser insuﬁcientes.

Caution:

rating.

Attention:

puissance aﬁn d’éviter tout risque d’incendie.

Vorsicht:

gleichen Typs und Nennwertes ersetzen.

Precauzione:

con altri dello stesso tipo e amperaggio.

L’utilisateur doit être informé que si le matériel est utilisé d’une façon non

Der Benutzer wird darauf aufmerksam gemacht, dass bei unsachgemäßer

l’utente deve essere al corrente del fatto che, se l’apparecchiatura viene

El usuario deberá saber que si el equipo se utiliza de forma distinta a la

To protect against ﬁre hazard, replace fuses with those of the same type and

Remplacez toujours les fusibles par d’autres du même type et de la même

Zum Schutz gegen Feuergefahr die Sicherungen nur mit Sicherungen des

per una buona protezione contro i rischi di incendio, sostituire i fusibili

Precaución:

el riesgo de incendio.

sustituya los fusibles por otros del mismo tipo y características para evitar

Caution:

power cord before servicing the instrument.

To avoid possible electrical shock, power off the instrument and disconnect the

Attention:

l’instrument et débranchez le cordon d’alimentation de la prise avant d’effectuer la maintenance de l’instrument.

Vorsicht:

abgeschaltet und vom Netz getrennt werden.

Precauzione:

il cavo di alimentazione prima di svolgere la manutenzione dello strumento.

Precaución:

de alimentación antes de realizar cualquier reparación en el instrumento.

Aﬁn d’éviter toute possibilité de commotion électrique, mettez hors tension

Zur Vermeidung von Stromschlägen sollte das Gerät vor der Wartung

per evitare il rischio di scossa elettrica, spegnere lo strumento e scollegare

para evitar choques eléctricos, apague el instrumento y desenchufe el cab le

Commonly Used Symbols

Direct current Courant continu Gleichstrom Corrente continua Corriente continua

Alternating current Courant alternatif Wechs el s t r om Corrente alternata Corriente alterna

Protective conductor terminal Borne du conducteur de protection Schutzleiteranschluss Terminale di conduttore con protezione Borne del conductor de tierra

Frame or chassis terminal Borne du cadre ou du châssis Rahmen- oder Chassisanschluss Terminale di struttura 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

Commonly Used Symbols

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

Caution, risk of electric shock (high voltage)•Attention, risque de commotion électrique (haute 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

(Continued)

Caution, ultraviolet light Attention, rayonnement ultrviolet Vorsicht, Ultraviolettes Licht Precauzione, luce ultravioletta Precaución, emisiones de luz ultravioleta

Waters 2410 Differential Refractometer Information

Intended Use

The W aters® 2410 Differential Refractometer can be used for in-vitro diagnostic testing to analyze many compounds, including diagnostic indicators and therapeutically monitoredcompounds. When you develop methods, follow the “Protocol for the Adoption ofAnalytical Methods in the Clinical Chemistry Laboratory,” American Journal ofMedical Technology, 44, 1, pages 30–37 (1978). This protocol covers good operatingprocedures and techniques necessary to validate system and method performance.

Biological Hazard

When you analyze physiological ﬂuids, take all necessary precautions 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, normal, and above-normal levels of a compound. Ensure that quality-control sample results are within an acceptable range, and evaluate 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.

How to Use This Guide Chapter 1

Waters 2410 Theory of Operation

1.1 Overview.........................................................................................................1-1

1.2 Theory of Operation........................................................................................ 1-2

1.2.1 Optical Refraction .............................................................................1-2

1.2.2 Differential Refractometry ................................................................1-7

1.2.3 Common RI Detection Problems ...................................................... 1-9

1.3 Principles of Operation.................................................................................. 1-10

1.3.1 Fluidics............................................................................................. 1-10

1.3.2 Optics .............................................................................................. 1-14

1.3.3 Electronics .......................................................................................1-15

Chapter 2 Installing the 2410 Refractometer

2.1 Introduction.....................................................................................................2-1

2.2 Site Selection and Power Requirements.......................................................... 2-2

2.3 Unpacking and Inspection............................................................................... 2-4

2.4 Making Electrical Power Connections............................................................ 2-5

2.5 Making Fluidic Connections...........................................................................2-5

2.5.1 Connecting a Column or Second Detector.........................................2-6

2.5.2 Connecting to Waste ......................................................................... 2-7

2.5.3 Connecting to a Drip Tray .................................................................2-8

Table of Contents xi

Chapter 3 Making Signal Connections

3.1 Component Connection Overview.................................................................. 3-1

3.2 Making IEEE-488 Signal Connections ........................................................... 3-3

3.2.1 Connecting to a Waters Data System Using the IEEE-488 Bus ........3-3

3.2.2 Connecting to a Waters PowerLine System Controller ..................... 3-7

3.2.3 Connecting to a Manual Injector .......................................................3-7

3.3 Making Non-IEEE-488 Signal Connections................................................... 3-8

3.3.1 Connecting to a Stand-Alone 2690 Separations Module.................3-10

3.3.2 Connecting to the Waters 745/745B/746 Data Module .................. 3-13

3.3.3 Connecting to a Chart Recorder ...................................................... 3-15

3.3.4 Connecting to the Waters 845/860 ExpertEase System ..................3-16

3.3.5 Connecting Injection Trigger Signals .............................................3-16

3.3.6 Polarity Connections .......................................................................3-18

3.4 Connecting the External Column Heaters..................................................... 3-19

Chapter 4 Preparing Solvents

4.1 Common Solvent Problems............................................................................. 4-1

4.2 Selecting a Solvent.......................................................................................... 4-2

4.3 Solvent Degassing........................................................................................... 4-4

4.3.1 Gas Solubility.....................................................................................4-5

4.3.2 Solvent Degassing Methods .............................................................. 4-5

4.3.3 Solvent Degassing Considerations .................................................... 4-6

Chapter 5 Using the 2410 Refractometer

5.1 Using the Front Panel...................................................................................... 5-1

5.1.1 Keypad Functions .............................................................................. 5-4

5.2 Selecting Parameter Values .............................................................................5-9

xii Table of Contents

5.2.1 Sensitivity Guidelines ........................................................................5-9

5.2.2 Scale Factor Guidelines ...................................................................5-10

5.2.3 Time Constant Guidelines ...............................................................5-11

5.2.4 Temperature Guidelines (Ext1 °C, Ext2 °C, Int °C) .......................5-12

5.2.5 Polarity Guidelines ..........................................................................5-13

5.3 Starting Up the 2410 Refractometer..............................................................5-13

5.4 Shutting Down the 2410 Refractometer........................................................5-15

Chapter 6 Maintenance Procedures

6.1 Cleaning the Fluidic Path.................................................................................6-1

6.2 Replacing Fuses...............................................................................................6-3

Chapter 7 Troubleshooting

7.1 Troubleshooting Overvie w ..............................................................................7-1

7.2 Chromatography Troubleshooting...................................................................7-2

7.2.1 Abnormal Baseline.............................................................................7-3

7.2.2 Erratic or Incorrect Retention Times .................................................7-7

7.2.3 Poor Peak Resolution ........................................................................7-9

7.2.4 Incorrect Qualitative/Quantitative Results ......................................7-11

7.3 Diagnostics ....................................................................................................7-13

7.3.1 Operating the Startup Diagnostics....................................................7-13

7.3.2 Operating the User-Initiated Diagnostics ........................................7-13

7.4 Hardware Troubleshooting ............................................................................7-16

Chapter Appendix A Speciﬁcations

Chapter Appendix B Spare Parts/Accessories

Table of Contents xiii

Appendix C Warranty Information

C.1 Limited Express Warranty...............................................................................C-1

C.2 Shipments, Damages, Claims, and Returns.....................................................C-4

Index

xiv Table of Contents

Figures

1-1 Waters 2410 Differential Refractometer..................................................1-1

1-2 Effect of Density on RI............................................................................ 1-4

1-3 Refraction of Light................................................................................... 1-5

1-4 Presence of Sample Changes the Photodiode Signal...............................1-6

1-5 How Refraction Changes

1-6 Waters 2410 Refractometer Fluidics...................................................... 1-11

1-7 Waters 2410 Refractometer Fluidic Paths..............................................1-13

1-8 Waters 2410 Differential Refractometer Optics Bench

Assembly Light Path..............................................................................1-15

2-1 Major Steps in Installing the 2410 Differential Refractometer................2-1

2-2 Dimensions of the 2410 Refractometer ................................................... 2-2

2-3 Waters 2410 Refractometer Rear Panel ...................................................2-4

2-4 Fluidic Connections.................................................................................2-6

2-5 Ferrule and Compression Screw Assembly ............................................. 2-7

.......................................................................1-8

3-1 Waters 2410 Differential Refractometer Rear Panel................................ 3-2

3-2 Overview of Connecting Components to the

2410 Differential Refractometer.............................................................. 3-3

3-3 Waters Millennium System IEEE-488 Connections................................ 3-4

3-4 Waters 845/860 System IEEE-488 Connections......................................3-4

3-5 Waters Alliance System IEEE-488 Connections .....................................3-5

3-6 Waters PowerLine System Controller IEEE-488 Connections................ 3-7

3-7 Waters 2410 Rear Panel Analog-Out/Event-In Connectors.....................3-9

3-8 Auto Zero Connections Between the 2690 Separations Module

and the 2410 Refractometer................................................................... 3-11

3-9 Chart Mark Connections Between the 2690 Separations Module

and the 2410 Refractometer................................................................... 3-12

3-10 Chart Mark and Auto Zero Connections Between

the 2690 Separations Module and the 2410 Refractometer................... 3-13

Table of Contents xv

3-11 Connections to a Waters 745/745B/746 Data Module........................... 3-14

3-12 Analog Output Connections to a Chart Recorder .................................. 3-15

3-13 Analog Output Connections to the Bus SAT/IN Module....................... 3-16

3-14 Auto Zero Connectionto a Manual Injector...........................................3-17

3-15 Chart Mark Connections to a Manual Injector ...................................... 3-18

3-16 2410 Refractometer External Column Heater Ports ..............................3-20

5-1 Display, LED Indicators, and Keypad......................................................5-2

5-2 Effects of Sensitivity Settings................................................................5-10

5-3 Effects of Filter Time Constant Settings................................................5-12

6-1 Removing and Replacing Fuses...............................................................6-4

xvi Table of Contents

Tables

1-1 Fluidic Line Inner Diameters............................................................ 1-12

2-1 Installation Site Requirements.................................................................2-3

3-1 Component Connection Summary...........................................................3-1

3-2 Waters 2410 Refractometer Inject Start Connections........................ 3-6

3-3 Waters 2410 Connections to a Manual Injector ................................ 3-7

3-4 Waters 2410 Analog-Out/Event-In Connections............................... 3-9

3-5 Auto Zero Connections Between the 2690 Separations Module

3-6 Chart Mark Connections Between the 2690 Separations Module

3-7 Chart Mark and Auto Zero Connections Between the

3-8 Analog Output Connections to a 745/745B/746 Data Module ........ 3-13

3-9 Analog Output Connections to a Chart Recorder............................ 3-15

and the 2410 Refractometer ........................................................... 3-10

and the 2410 Refractometer ........................................................... 3-11

2690 Separations Module and the 2410 Refractometer................... 3-12

3-10 Analog Output Connections to the Bus SAT/IN Module................. 3-16

3-11 Auto Zero Connections to a Manual Injector.................................. 3-17

3-12 Chart Mark Connections to a Manual Injector ................................ 3-18

3-13 Polarity Options............................................................................. 3-19

4-1 Refractive Indices of Common Solvents..................................................4-3

5-1 Indicator LED Functions..........................................................................5-3

5-2 Keypad Functions............................................................................ 5-4

6-1 Voltage and Fuse Requirements...............................................................6-4

7-1 Abnormal Baseline Troubleshooting................................................ 7-4

7-2 Retention Time Troubleshooting...................................................... 7-7

Table of Contents xvii

7-3 Resolution Troubleshooting ........................................................... 7-10

7-4 Incorrect Results Troubleshooting.................................................. 7-12

7-5 User Diagnostics............................................................................ 7-14

7-6 Waters 2410 Hardware Troubleshooting ......................................... 7-16

A-1 Operational Speciﬁcations...................................................................... A-1

A-2 Integrator Output..............................................................................A-2

A-3 Optical Component Speciﬁcations....................................................A-2

A-4 Environmental Speciﬁcations...........................................................A-2

A-5 Dimensions ......................................................................................A-3

A-6 Electrical Speciﬁcations...................................................................A-3

A-7 Power Source Speciﬁcation..............................................................A-3

B-1 Recommended Spare Parts ...............................................................B-1

C-1 Waters 2410 Warranty Periods.................................................................C-4

xviii Table of Contents

How to Use This Guide

Purpose of This Guide

The

Waters 2410 Differential Refractometer Operator’ s Guide

Waters® 2410 Differential Refractometer and provides installation and maintenance procedures.

Audience

This guide is intended for use by anyone interested in installing, using, maintaining, and troubleshooting the 2410 differential refractometer.

Structure of This Guide

The

Waters 2410 Differential Refractometer Operator’s Guide

appendixes. Each page is marked with a tab and a footer to facilitate access to information within the chapter or appendix.

The table below describes the material covered in each chapter and appendix.

describes the features and use of the

is divided into chapters and

Chapter 1, Waters 2410 Theory of Operation

Chapter 2, Installing the 2410 Refractometer

Chapter 3, Making Signal Connections

Chapter 4, Preparing Solvents

Chapter 5, Using the 2410 Refractometer

Chapter 6, Maintenance Procedures

Chapter 7, Troubleshooting

Describes the product and the principles of differential refractometry and 2410 differential refractometer operation.

Describes the 2410 differential refractometer installation procedures.

Describes how to connect other components of your chromatography system to the 2410 differential refractometer.

Discusses the importance of ﬁltering and degassing solvents for effective operation.

Describes how to power on and off and operate the 2410 differential refractometer.

Describes maintenance and parts replacement procedures for the 2410 differential refractometer.

Provides tables describing symptoms, possible causes, and corrective actions for 2410 differential refractometer operational problems.

xix

Appendix A, Speciﬁcations

Provides speciﬁcations for the 2410 differential refractometer.

Appendix B, Spare Parts/Accessories

Appendix C, Warranty Information

Lists the recommended spare parts for the 2410 differential refractometer.

Includes warranty and service information for the 2410 differential refractometer.

Waters 2410 Theory of Operation

1.1 Overview ........................................................... 1-1

1.2 Theory of Operation.......................................... 1-2

1.3 Principles of Operation.................................... 1-10

Waters 2410 Theory of Operation

This chapter introduces you to the Waters® 2410 Differential Refractometer. It summarizes the 2410 differential refractometer features and the principles of differential refractometry, and describes the theory and principles of operation.

Refer to Appendix A, Speciﬁcations, for system speciﬁcations, and to

Solvents

1.1 Overview

The Waters 2410 Differential Refractometer, shown in Figure 1-1, is a differential refractive index detector designed for high performance liquid chromatography applications. It can operate as a stand-alone unit with an integrator or chart recorder, or with a Waters system controller or Waters data system.

, for solvent considerations.

Chapter 4, Preparing

Waters 2410

Differential Refractometer Detector

TP01531

Figure 1-1 Waters 2410 Differential Refractometer

Overview 1-1

Range and Sensitivity

The 2410 detector functions with solvents with refractive indices between 1.00 and 1.75. The measurement range of the instrument is 5 × 10–8 to 5 × 10–3 refractive index units full scale (RIUFS).

Features

Features of the 2410 differential refractometer include:

• Patented countercurrent heat exchanger and temperature-controlled cell for stable operation under varying conditions

• Auto zero and auto purge for automated operation

• Built-in pressure relief to protect ﬂow cell

• Auto diagnostics

• Two external column heater controls

• Battery backup to retain parameter settings when the detector is powered off or during power interruptions

• Long-life LED light source

1.2 Theory of Operation

The W aters 2410 Dif ferential Refractometer uses optical refraction to monitor the concentrations of sample components in your eluent. This section describes:

• Optical refraction

• Differential refractometry

• Common problems in refractometry

1.2.1 Optical Refraction

When a beam of light passes from one medium into another, it changes its speed. If the light enters the second medium at an angle that is not perpendicular to the medium’s surface, the light is bent (refracted).

The extent to which a medium refracts light is its velocity of light in a vacuum to the velocity of light in the medium. It is a physical property of the medium, with a dimensionless integer value represented by the letter n.

This section discusses:

• Factors that affect RI

1-2 Waters 2410 Theory of Operation

refractive inde x

(RI), calculated as the ratio of the

• Measuring refraction

• Using changes in RI for sample detection

Factors That Affect RI

The refractive index of a medium is solely dependent on the speed of light in the medium. The speed of light in a medium is constant for a given wa velength of light at a speciﬁed temperature and pressure.

Wavelength

The refractive index of a medium has a speciﬁc value that changes with the wavelength of the incident light beam. Since the 2410 differential refractometer uses monochromatic light at a ﬁxed wavelength, the effect of different wavelengths of light on RI is not discussed in this guide.

Density

The density of the medium also affects its RI. At a ﬁxed wavelength, the relationship between the density of a medium and its RI is generally, but not necessarily, linear. The most important of the factors that affect the density of a medium are:

• Composition

• Temperature

• Pressure

Figure 1-2 illustrates the effect of density on the RI of two solutions. The refractive index of a sucrose solution changes linearly with concentration over this range of compositions, but a methanol solution exhibits a nonlinear region between concentrations of 45 and 55 percent.

Theory of Operation 1-3

Weight Percent Sucrose in Water

Refractive Index

Density (g/mL)

Weight Percent Methanol in Water

Refractive Index

Figure 1-2 Effect of Density on RI

1-4 Waters 2410 Theory of Operation

Density (g/mL)

Measuring Refraction

The extent to which a beam of light is refracted when it enters a medium depends on two factors:

• The angle at which the light enters the new medium (the

• The refractive indices of the new media

angle of incidence

)

The angle of a refracted light beam through the new medium is its

angle of refraction

Figure 1-3 illustrates the relationship between angle of incidence, angle of refraction, and refractive index.

Incoming Light Beam Perpendicular to Surface

Angle of Incidence

Medium 1, RI = n Medium 2, RI = n

Refracted Light Beam

1 2

Angle of Refraction

Figure 1-3 Refraction of Light

The relationship between the refractive indices of the two media and the angles of incidence and refraction is described by Snell’s Law:

n1(sin

where:

= Angle of incidence

= Angle of refraction

= RI of medium 1

= RI of medium 2

) = n2(sin

)

Theory of Operation 1-5

You can use Snell’s Law to calculate the RI of a sample solution from the angle of incidence, the RI of the solvent, and the angle of refraction.

Using Changes in RI for Sample Detection

As the separated components of a sample pass through the refractometer ﬂow cell:

• The composition of the sample solution in the ﬂow cell changes.

• The RI of the solution changes.

• The light beam passing through the solution is refracted.

The refractometer detects the position of the refracted light beam, creating a signal that differs from the baseline signal.

Figure 1-4 shows how refraction by the sample in the ﬂow cell changes the proportion of light on each element of the photodiode.

Dual Element

Dual-Element

Photodiode

Collimating

Collimating Lens

Lens

Sample Side

Sample Side of Flow Cell

of Flow Cell

Sample in

Sample Side

of Flow Cell

Reference

Reference Side of Flow Cell

Side of

Flow Cell

Figure 1-4 Presence of Sample Changes the Photodiode Signal

1-6 Waters 2410 Theory of Operation

Incident Light

Reference Side

of Flow Cell

Reference Side of Flow Cell

+ 116 hidden pages

Waters 2410 Operator's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

How to Use This Guide

Waters 2410 Theory of Operation

1.1 Overview

1.2 Theory of Operation

1.2.1 Optical Refraction