Wyatt Technology Optilab rEX User manual

Optilab rEX
User’s Guide
(M1500 Rev. F)

WYATT TECHNOLOGY Corporation makes no warranties, either express or implied,
regarding this instrument, computer software package, its merchantability or its fitness
for any particular purpose. The software is provided “as is”, without warranty of any
kind. Furthermore, Wyatt Technology does not warrant, guarantee, or make any repre-
sentations regarding the use, or the results of the use, of the software or written materi-
als in terms of correctness, accuracy, reliability, currentness, or otherwise. The exclusion
of implied warranties is not permitted by some states, so the above exclusion may not
apply to you.
Copyright © 2008, Wyatt Technology Corporation. All rights reserved.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval
system, or transmitted, in any form by any means, electronic, mechanical, photocopying,
recording, or otherwise, without the prior written permission of Wyatt Technology Corpo-
ration.
® DAWN, ASTRA, DNDC, and Optilab are registered trademarks of Wyatt Technology
Corporation.
A variety of U.S. and foreign patents have been issued and/or are pending on various
aspects of the apparatus and methodology implemented by this instrumentation.

Optilab rEX User’s Guide (M1500 Rev. F)iii
Contents
Chapter 1: About the Optilab rEX ........................................... 1-1
1.1 Methods of Measuring Refractive Indexes .................................................. 1-2
1.2 Using This Manual ...................................................................................... 1-3
1.3 Contacting Wyatt Technology ...................................................................... 1-4
Chapter 2: Instrument Description ......................................... 2-1
2.1 Overview ..................................................................................................... 2-2
2.2 Front Panel .................................................................................................. 2-3
2.3 Rear Panel .................................................................................................. 2-4
Chapter 3: Quick Start.............................................................. 3-1
3.1 Setting Up the Optilab rEX .......................................................................... 3-2
Chapter 4: Installation and Setup ........................................... 4-1
4.1 Power and Signal Connections ................................................................... 4-2
4.1.1 Power Connector ............................................................................................4-2
4.1.2 Signal Connectors ...........................................................................................4-2
4.1.3 Communication Connector ..............................................................................4-7
4.2 Fluid Connections ....................................................................................... 4-7
4.3 Dry Nitrogen Connection ............................................................................. 4-8
4.4 Power On and Warm Up ............................................................................. 4-9
4.5 Purging the Optilab rEX .............................................................................. 4-9
4.6 Instrument Stability Check ......................................................................... 4-10
Chapter 5: Using the LCD Display.......................................... 5-1
5.1 Navigating the Optilab rEX Tabs ................................................................. 5-2
5.2 Main Tab ...................................................................................................... 5-3
5.3 aRI Tab ........................................................................................................ 5-4
5.4 Alarms Tab .................................................................................................. 5-5
5.5 System Tab ................................................................................................. 5-7
5.5.1 Constants Dialog .............................................................................................5-9
5.5.2 LED Intensity Dialog ......................................................................................5-11
5.6 Communications Tab ................................................................................. 5-13
Chapter 6: Off-Line Measurements......................................... 6-1
6.1 Instrument Calibration for dRI ..................................................................... 6-2
6.1.1 General Information and Sample Preparation .................................................6-2
6.1.2 HPLC Pump with Injector ................................................................................6-3
6.1.3 Syringe Pump Infusion ....................................................................................6-3
6.1.4 Collecting Data for Optilab rEX dRI Calibration ..............................................6-4

Contents
iv Optilab rEX User’s Guide (M1500 Rev. F)
6.2 dn/dc Measurement .................................................................................... 6-6
6.3 Instrument Calibration for aRI ..................................................................... 6-7
6.3.1 General Information ........................................................................................6-7
6.3.2 Collecting Data for Optilab rEX aRI Calibration ..............................................6-7
6.4 Absolute Refractive Index Measurement .................................................. 6-10
Chapter 7: In-Line HPLC Detection......................................... 7-1
7.1 Conditions for In-Line Operation ................................................................. 7-2
7.2 Sample Preparation .................................................................................... 7-3
7.3 Measurement .............................................................................................. 7-3
Chapter 8: Service and Maintenance...................................... 8-1
8.1 Replacing the LED/Fiber Light Source ........................................................ 8-2
8.2 Cleaning After a Fluid Leak ........................................................................8-11
8.3 Cleaning the Air Intake Filter ..................................................................... 8-12
8.4 Changing a Fuse ....................................................................................... 8-12
8.5 Optilab rEX Firmware Upgrades ............................................................... 8-13
Chapter 9: Troubleshooting .................................................... 9-1
9.1 Low Light Alarm .......................................................................................... 9-2
9.2 Temperature Will Not Set Below 20 C ......................................................... 9-3
9.3 Noisy Baseline ............................................................................................ 9-4
9.4 Microsoft Windows Encounters Problems ................................................... 9-4
Appendix A: Acronyms and Abbreviations List................... A-1
A.1 Acronyms and Abbreviations ......................................................................A-2
Appendix B: Operating Principles and Theory..................... B-1
B.1 Basic Principles ..........................................................................................B-2
B.1.1 Conventional Flow Cell ................................................................................. B-2
B.1.2 Optilab rEX Flow Cell ..................................................................................... B-3
B.2 Measurement of the Beam Deflection Angle ..............................................B-4
B.2.1 Conventional Split Photodiode Based Instrument ........................................ B-4
B.2.2 Wyatt Technology Corporation Beam Positioning Technology ......................B-4
Appendix C: Optilab rEX Specifications ............................... C-1
C.1 Specifications .............................................................................................C-2
Appendix D: Wire Colors........................................................ D-1
D.1 Earlier Cable Revisions ..............................................................................D-2
Appendix E: Instrument Connectivity................................... E-1
E.1 Introduction .................................................................................................E-2

Contents
Optilab rEX User’s Guide (M1500 Rev. F)v
E.2 Components Used ......................................................................................E-3
E.2.1 Instrument Connections ................................................................................. E-3
E.2.2 LAN Connection ............................................................................................. E-4
E.2.3 Computer Connections .................................................................................. E-4
E.2.4 Crossover Cable ............................................................................................ E-5
E.2.5 Ethernet Cable ............................................................................................... E-5
E.2.6 Ethernet to USB Adapter ............................................................................... E-6
E.2.7 Ethernet Switch .............................................................................................. E-7
E.3 Connecting to a LAN ...................................................................................E-8
E.3.1 One Instrument to LAN .................................................................................. E-8
E.3.2 One Instrument and Computer to LAN .......................................................... E-9
E.3.3 Multiple Instruments to LAN ......................................................................... E-10
E.3.4 Multiple Instruments and Computer to LAN ..................................................E-11
E.4 Connecting via USB ..................................................................................E-12
E.4.1 One Instrument to USB via a Crossover Cable ........................................... E-12
E.4.2 One Instrument to USB Using an Ethernet Switch ...................................... E-13
E.4.3 Multiple Instruments to USB ........................................................................ E-14
E.5 Connecting via Ethernet When Not on a LAN ..........................................E-15
E.5.1 One Instrument to Computer Using Crossover Cable ................................. E-15
E.5.2 One Instrument to Computer Using an Ethernet Switch .............................. E-16
E.5.3 Multiple Instruments to Computer Using an Ethernet Switch ...................... E-16
E.6 Instrument Network Settings .....................................................................E-17
E.7 Accessing Instruments with ASTRA V ......................................................E-18
E.8 Troubleshooting and Diagnostics .............................................................E-19
E.8.1 Windows XP Professional Service Pack 2 ................................................... E-19
E.8.2 ASTRA V Settings ....................................................................................... E-19
E.8.3 Verifying Instrument Connections ................................................................ E-19
Appendix F: Warnings ............................................................. F-1
F.1 List of Warnings ...........................................................................................F-2
Index .................................................................................. Index-1

vi Optilab rEX User’s Guide (M1500 Rev. F)

Optilab rEX User’s Guide (M1500 Rev. F)1-1
1About the Optilab rEX
This chapter provides a general introduction to the Optilab rEX instru-
ment and an overview of the sections in this manual.
CONTENTS PAGE
1.1 Methods of Measuring Refractive Indexes..................................... 1-2
1.2 Using This Manual.......................................................................... 1-3
1.3 Contacting Wyatt Technology......................................................... 1-4

Chapter 1: About the Optilab rEX
1-2 Optilab rEX User’s Guide (M1500 Rev. F)
1.1 Methods of Measuring Refractive Indexes
For the past four decades, virtually all differential Refractive Index (dRI)
detector manufacturers have used a deflection-based instrument design to
measure the refractive index difference between a reference fluid and a
sample fluid. Wyatt Technology’s Optilab DSP stood alone as an interfero-
metric-based instrument with the ability to cool samples below ambient
temperatures. When the Optilab DSP was introduced, an interferometric-
based design was the most sensitive method available for measuring dRI.
However, technology does not remain motionless. Significant advances
over the past five years in nanoscale semiconductor fabrication tech-
niques, linear photodiode array technology, and computer speed have
allowed Wyatt Technology to develop a novel deflection-based dRI instru-
ment that surpasses all current measurement methods.
The Optilab rEX (refractometer with EXtended range) is a deflection-
based instrument that pioneers the use of an array of light sensitive detec-
tors in the measurement of dRI. It has a linear array of 512 photodiodes,
rather than the traditional two photodiodes used by other deflection-based
instruments. This photodiode array allows for unprecedented sensitivity
and range.
With most RI instruments, users must choose a gain setting, which essen-
tially means choosing between good sensitivity over a limited range,
reduced sensitivity over a large range, or some compromise between the
two. The Optilab rEX has no gain settings; the maximum sensitivity exists
over the entire range. Tiny signals and huge signals may be measured
within the same data run. The ability to see both large and small signals
may be quantified by the instrument’s dynamic range (defined as range
divided by noise). The dynamic range of the Optilab rEX is 2.35 million,
literally orders of magnitude greater than any other RI instrument on the
market today.
In addition to the photodiode array, the Optilab rEX contains a new flow
cell design that allows the measurement of a fluid’s absolute Refractive
Index (aRI) in addition to the dRI between two fluids. The aRI of a fluid is
vital for characterizing a system and is a necessary input parameter for
light scattering measurements that determine the molecular mass of mol-
ecules in solution.

Using This Manual
Optilab rEX User’s Guide (M1500 Rev. F)1-3
1.2 Using This Manual
The organization of this manual is as follows:
•Chapter 2, “Instrument Description”: Describes the Optilab rEX
instrument’s control interfaces and connections.
•Chapter 3, “Quick Start”: Contains a summary of instructions for
setting up the Optilab rEX quickly and with minimal instruction.
•Chapter 4, “Installation and Setup”: Provides detailed connection
information for installation and setup.
•Chapter 5, “Using the LCD Display”: Provides detailed information
on how to use the tabs on the LCD display to control, configure, and
monitor the Optilab rEX.
•Chapter 6, “Off-Line Measurements”: Describes how to make
static measurements with the Optilab rEX, including instrument cali-
bration, off-line dn/dc measurements, and absolute refractive index
measurements.
•Chapter 7, “In-Line HPLC Detection”: Describes using the Optilab
rEX as an in-line concentration sensitive detector for HPLC.
•Chapter 8, “Service and Maintenance”: Provides maintenance and
service instructions.
•Chapter 9, “Troubleshooting”: Provides troubleshooting tips.
•Appendix A, “Acronyms and Abbreviations List”: Contains a list
of acronyms and abbreviations used in this manual.
•Appendix B, “Operating Principles and Theory”: Provides a basic
and theoretical description of how the Optilab rEX operates.
•Appendix C, “Optilab rEX Specifications”: Provides the specifica-
tions of the Optilab rEX.
•Appendix D, “Wire Colors”: Provides information about earlier revi-
sions of the general-purpose cable supplied by Wyatt Technology
Corporation.
•Appendix E, “Instrument Connectivity”: Provides details about
connecting the Optilab rEX to a computer.
•Appendix F, “Warnings”: Lists warnings to be aware of when using
the Optilab rEX.
•Index: Provides lookup assistance.

Chapter 1: About the Optilab rEX
1-4 Optilab rEX User’s Guide (M1500 Rev. F)
1.3 Contacting Wyatt Technology
We solicit and encourage questions and comments about this manual and
the Optilab rEX instrument. Please contact:
Technical Support Department
Wyatt Technology Corporation
6300 Hollister Avenue
Santa Barbara, CA 93117
Telephone: [phone]
FAX: [phone]
E-mail: [email protected]

Optilab rEX User’s Guide (M1500 Rev. F)2-1
2Instrument Description
This chapter provides an overview of the Optilab rEX features.
CONTENTS PAGE
2.1 Overview......................................................................................... 2-2
2.2 Front Panel..................................................................................... 2-3
2.3 Rear Panel...................................................................................... 2-4

Chapter 2: Instrument Description
2-2 Optilab rEX User’s Guide (M1500 Rev. F)
2.1 Overview
The Optilab rEX measures the dRI between the current liquid sample
stream and a liquid (usually clean solvent) previously stored as a refer-
ence. The dRI is measured at a fixed wavelength determined by a Light
Emitting Diode (LED)/fiber light source. The light source consists of a
high-powered LED coupled to a special optical fiber. This “pigtail” configu-
ration allows you to easily replace the light source. If you want to change
the measurement wavelength, installing a “pigtail” with a different wave-
length accomplishes this.
The dRI data can be read from the LCD display, the analog output
channel, or digitally through the Ethernet port. Since the dRI of liquids
depends critically on temperature, the instrument has a system that pre-
cisely regulates the temperature of both the flow cell and the optics.
In addition to the dRI between two liquids, with the same liquid present in
the sample and reference chambers, the Optilab rEX measures the aRI of
that liquid.
For a more detailed theoretical description, see Appendix B, “Operating
Principles and Theory”.

Front Panel
Optilab rEX User’s Guide (M1500 Rev. F)2-3
2.2 Front Panel
The front panel, see Figure 2-1, provides fluid connections for the Optilab
rEX and all of the necessary functions and displays for operating the
instrument and monitoring data.
Figure 2-1: Front panel
Front Panel Door: The front panel door opens to provide access to the IN
and OUT fluid connections for the Optilab rEX.
LCD Display: The LCD display provides a full-color, high-resolution user
interface to the Optilab rEX. It allows you to monitor, control and config-
ure the instrument. Chapter 5, “Using the LCD Display” describes all
of the tabs available on the LCD display and their functions.
Keypad: The keypad allows you to control the LCD display. “Navigating
the Optilab rEX Tabs” on page 5-2 describes how to use the keypad to
navigate through the LCD display tabs.
IN/OUT Fluid Connectors: Fluid comes into the Optilab rEX through
the IN port, and exits through the OUT port. The Optilab rEX should be
connected last in line if other detectors are connected in series.
Liquid Leak Port: The liquid leak port provides an exit for any liquid
that leaks from internal or external fittings. The Teflon tubing provided
may be fit over this tubing and directed to a fluid waste bottle. When a
liquid leak occurs, an internal liquid sensor activates an alarm shown on
the LCD display (see “Alarms Tab” on page 5-5), and activates an Alarm
Out signal that may be used to shut off a pump.
Power Switch: The power switch turns instrument power On and Off.
Front Panel Door LCD Display
Power Switch
Keypad
Liquid Leak Port

Chapter 2: Instrument Description
2-4 Optilab rEX User’s Guide (M1500 Rev. F)
2.3 Rear Panel
The rear panel, see Figure 2-2, provides access for power, signal connec-
tions, the cooling fan, air filter, the exhaust fan, and a nitrogen purge port.
Figure 2-2: Rear panel
Air Intake and Exhaust Fans: The fans help to keep the instrument
electronics at a constant temperature.
Signal Connectors: There are 10 RJ-12 connectors that provide connec-
tions to Transistor-Transistor Logic (TTL) inputs and outputs, Analog
input and output, Auto Inject input and output, and a solenoid drive
output. For a description of the signal connectors, see “Power and Signal
Connections” on page 4-2.
Power Connector: Provides power to the instrument. See “Power and
Signal Connections” on page 4-2 for a complete description of the Optilab
rEX’s power requirements.
Communications Connector: The Ethernet connector allows you to
connect to a computer or an Ethernet network.
Nitrogen Purge Port: Provides the connection to purge the instrument
with dry nitrogen in order to prevent condensation on the optical and mea-
surement systems. For detailed information regarding the nitrogen purge
port, see “Dry Nitrogen Connection” on page 4-8.
Power Connector
Air Intake Fan Air Exhaust Fan
Nitrogen Purge Port
Communications Connector
Signal Connectors

Optilab rEX User’s Guide (M1500 Rev. F)3-1
3Quick Start
This chapter provides rudimentary setup procedures for first-time or expe-
rienced users who want to start the Optilab rEX installation process
before reading the entire manual.
Detailed descriptions and important use instructions concerning the
Optilab rEX are provided in the chapters that follow.
CONTENTS PAGE
3.1 Setting Up the Optilab rEX ............................................................. 3-2

Chapter 3: Quick Start
3-2 Optilab rEX User’s Guide (M1500 Rev. F)
3.1 Setting Up the Optilab rEX
This section describes basic setup procedures for those who want to begin
using the Optilab rEX as soon as possible.
More details about setting up the Optilab rEX are provided in Chapter 4,
“Installation and Setup”. (You may notice that the setup sequence in
this chapter differs a bit from that in Chapter 4. The sequence in this
chapter allows you to begin stabilizing the temperature earlier in the
sequence.)
See Chapter 2, “Instrument Description” for descriptions of the front
and rear panel controls and connections.
For instructions on navigating the LCD display tabs, see “Navigating the
Optilab rEX Tabs” on page 5-2.
Note: The Optilab rEX can be safely stacked above and below other instruments.
1. Connect the power cable.The power outlet is located on the Optilab
rEX rear panel (see Figure 2-2). The power supply is universal, for
immediate use with 100–120 V or 220–240 V power at 50-60 Hz. (See
also “Power and Signal Connections” on page 4-2.)
2. Power ON the Optilab rEX.Time to full warm-up is approximately
30 minutes. (See also “Power On and Warm Up” on page 4-9.)
3. Set temperature. The Optilab rEX default temperature is 25°C, with
a range of 4°C to 50°C. (If you are operating below 25°C, it is important
that you see “Dry Nitrogen Connection” on page 4-8 before cooling the
instrument.)
4. Make fluid connections. Standard HPLC fittings: 1/16 in. OD tub-
ing, 10-32 threads. The Optilab rEX should be connected last in line if
other detectors are to be connected in series. (See also “Fluid Connec-
tions” on page 4-7.) The IN and OUT ports are located behind a door on
the front panel (see Figure 2-1).
Tubing recommendations are:
• 0.010 in. (0.254 mm) ID to the Optilab rEX IN port.
• 0.020 in. (0.508 mm) or larger ID from the Optilab rEX OUT port
to a waste bottle or solvent recycle valve.
5. Flush the Optilab rEX in purge mode. Use 20 mL of co-miscible
solvents stepwise as necessary to prepare the cell for data collection.
(See also “Purging the Optilab rEX” on page 4-9.) Tab to the Purge
On/Off button using the front panel arrow keys (see Figure 2-1).

Setting Up the Optilab rEX
Optilab rEX User’s Guide (M1500 Rev. F)3-3
The Optilab rEX is shipped with Ethanol in the flow cell. A typical
series of solvents (from polar to nonpolar) is shown below. Salt solu-
tions should be considered separate steps from pure solvents.
6. Zero the instrument. Activate the Zero selection on the Optilab rEX
LCD display. (See also “Main Tab” on page 5-3)
7. Install software.
a. For in-line use with chromatography, install ASTRA or equivalent
chromatography software. See the appropriate software manual
for installation instructions.
b. For off-line use (e.g., dn/dc determinations), install ASTRA V soft-
ware. See the appropriate software manual for installation instruc-
tions.
8. Connect communication cable. (See also “Power and Signal Con-
nections” on page 4-2.)
a. If data is to be collected using the ASTRA V software, connect the
Optilab rEX directly to a computer or local area network (LAN)
using the Ethernet cable provided.
b. If data is to be collected using ASTRA 4.X, DNDC, or other soft-
ware, connect the Optilab rEX analog output to a DAWN or
miniDAWN instrument’s analog input AUX1 port using the analog
cable provided.
Water
Methanol, Ethanol
Isopropanol, Acetone
Tetrahydrofuran
Ethylacetate, Chloroform, Methylene chloride
Toluene, Carbon disulfide
Hexane, Petroleum ether

Chapter 3: Quick Start
3-4 Optilab rEX User’s Guide (M1500 Rev. F)

Optilab rEX User’s Guide (M1500 Rev. F)4-1
4Installation and Setup
This chapter describes the fluid, power, and signal connections used in
setting up the Optilab rEX.
CONTENTS PAGE
4.1 Power and Signal Connections ...................................................... 4-2
4.1.1 Power Connector....................................................................... 4-2
4.1.2 Signal Connectors..................................................................... 4-2
4.1.3 Communication Connector........................................................ 4-7
4.2 Fluid Connections........................................................................... 4-7
4.3 Dry Nitrogen Connection................................................................ 4-8
4.4 Power On and Warm Up ................................................................ 4-9
4.5 Purging the Optilab rEX.................................................................. 4-9
4.6 Instrument Stability Check.............................................................. 4-10

Chapter 4: Installation and Setup
4-2 Optilab rEX User’s Guide (M1500 Rev. F)
4.1 Power and Signal Connections
All power and signal connections to the Optilab rEX are made using the
interfaces on the rear panel of the instrument. Refer to Figure 4-1 to view
the connectors on the rear panel of the Optilab rEX.
Figure 4-1: Rear panel power and signal connections
4.1.1 Power Connector
The power input accepts 100–250 VAC at 50–60 Hz. The power input
module contains two fuses, each rated at 2 Amps, one for the line voltage
in, and the other for the line voltage return.
4.1.2 Signal Connectors
The instrument rear panel contains 10 RJ-12 connectors for TTL inputs
and outputs, analog input and output, auto inject input and output, and a
solenoid drive output.
Cables not supplied by Wyatt Technology may use a different color code
scheme or have a different correspondence between color and pin number.
If you are using non-Wyatt Technology supplied cables, refer to Figure 4-2
and Table 4-1 to determine the correct pin number and wire usage. We
recommend using only cables supplied by Wyatt Technology; wiring the
connection incorrectly could damage your instrument.
Pinouts for the RJ-12 connectors used in Wyatt Technology-supplied
cables are shown in Figure 4-2.