Hach AutoCAT 9000 User manual

50081-18
Chlorine Amperometric Titrator
© Hach Company, 2002–2003, 2007. All rights reserved. Printed in the USA. pks 4/07 3ed

50081_TTL.fm

Table of Contents
50081_BookTOC.fm Page 1
Table of Contents
Safety Information..................................................................................................................................................5
Specifications...........................................................................................................................................................7
Section 1 Introduction................................................................................................................................9
1.1 General Information............................................................................................................................................9
1.2 Instrument Startup Summary ..............................................................................................................................9
1.3 Unpacking.........................................................................................................................................................10
1.4 User Access Levels........................................................................................................................................... 11
Section 2 Instrument Assembly............................................................................................................13
2.2 Instrument Assembly ........................................................................................................................................15
2.2.1 Attaching the Titrant Bottle Holder .........................................................................................................15
2.2.2 Connecting the Electrode Head and Accessories.....................................................................................15
2.2.3 Connecting the Titrant Bottle...................................................................................................................16
2.2.4 Assembling the Burette ...........................................................................................................................17
2.2.5 Connecting the Temperature Sensor .......................................................................................................18
2.2.6 Installing the Electrode ...........................................................................................................................19
2.2.7 Power Connection....................................................................................................................................19
2.2.8 Serial Printer and PC Connections...........................................................................................................20
Operation...............................................................................................................................................................21
Section 3 Basic Operation.......................................................................................................................23
3.1 Instrument Display and Keypad .......................................................................................................................23
3.2 AutoCAT Main Menus......................................................................................................................................24
3.2.1 How to Access the Menus........................................................................................................................24
3.2.2 Methods Menu .........................................................................................................................................24
3.2.3 Titrants Menu...........................................................................................................................................25
3.2.3.1 Changing Titrants ..............................................................................................................25
3.2.3.2 Daily Start-up .....................................................................................................................26
3.2.4 Electrodes Menu ......................................................................................................................................26
3.2.5 Cell Menu.................................................................................................................................................27
3.3 System Configuration .......................................................................................................................................27
3.3.1 Entering the Supervisor Code ..................................................................................................................27
3.3.2 Setting a User ID......................................................................................................................................27
3.3.3 Choose a Language ..................................................................................................................................27
3.3.4 Set the Time .............................................................................................................................................28
3.3.5 Set the Date ..............................................................................................................................................28
3.3.5.1 Select Optional PC Keyboard ............................................................................................28
3.3.6 Selecting the ac Power Frequency ...........................................................................................................28
3.3.7 Printer Status ............................................................................................................................................29
3.3.8 Beep ON/OFF ..........................................................................................................................................29

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Page 2 50081_BookTOC.fm
3.3.9 Rules for Routine Access Users...............................................................................................................29
3.3.10 Customizing the Station.........................................................................................................................30
3.3.11 Reset to Factory Settings........................................................................................................................30
3.3.12 Exit.........................................................................................................................................................30
3.4 Edition Mode ....................................................................................................................................................30
3.5 Using Sub-ID's..................................................................................................................................................31
Section 4 Software Setup.........................................................................................................................33
4.1 Accessing Supervisor Mode .............................................................................................................................33
4.2 Software Setup for Electrode and Temperature Sensor Installation .................................................................34
4.2.1 Software Setup for Disconnecting or Replacing Electrodes....................................................................35
4.3 Software Setup for Burette Installation ............................................................................................................36
4.3.1 Software Setup for Removing or Replacing the Burette .........................................................................37
4.4 Software Setup for Titrant Installation..............................................................................................................38
4.4.1 Software Setup for Switching or Replacing Titrants ...............................................................................39
4.5 Setting Titrant Concentration............................................................................................................................40
4.6 Obtaining the Certificate of Analysis for Hach Reagents.................................................................................41
Section 5 Collecting and Accessing Data ..........................................................................................43
5.1 Using the AutoCAT 9000 for Amperometric Methods ....................................................................................43
5.2 AutoCAT Titration ............................................................................................................................................43
5.2.1 Data Collection ........................................................................................................................................43
5.2.1.1 Current Range ....................................................................................................................43
5.2.1.2 Volume Increment .............................................................................................................44
5.2.1.3 Predose Volume .................................................................................................................44
5.2.1.4 Auto-scaling .......................................................................................................................44
5.2.2 End Point Determination..........................................................................................................................44
5.2.2.1 Manual End Point Determination (MEPD) .......................................................................45
5.2.2.2 Automatic End Point Determination (AEPD) ...................................................................45
5.2.2.3 Auto Detection ...................................................................................................................45
5.2.3 Parameters Used in the Calculation of the Analyte Concentration..........................................................45
5.2.3.1 Titrant Concentration .........................................................................................................45
5.2.3.2 Sample Volume ..................................................................................................................45
5.2.3.3 Dilution ..............................................................................................................................46
5.2.3.4 Reductant Concentration ....................................................................................................46
5.2.3.5 Reductant Volume .............................................................................................................46
5.2.4 Analysis Calculations...............................................................................................................................46
5.2.4.1 Calculation of Mean ...........................................................................................................47
5.2.4.2 Calculation of Standard Deviation (<5 replicate analyses) ...............................................47
5.2.4.3 Calculation of Standard Deviation (>5 replicate analyses) ...............................................47
5.2.5 Retrieving Analysis Results from Archives.............................................................................................48

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Table of Contents
50081_BookTOC.fm Page 3
Section 6 Calibration Procedures ........................................................................................................49
PAO/5.64 mN, Amperometric Forward Titrant Calibration...................................................................................51
Iodine, Amperometric Back Titrant Calibration ..................................................................................................... 57
Section 7 Sampling ....................................................................................................................................63
7.1 Chlorine ............................................................................................................................................................63
7.2 Container Pretreatment .....................................................................................................................................63
7.3 Handling............................................................................................................................................................63
7.4 Samples for Back Titration ...............................................................................................................................63
Section 8 Titration Procedures .............................................................................................................65
Chlorine Dioxide
Generator Yield, Amperometric Forward Titration .............................................................................................67
Chlorine Dioxide, Amperometric Forward Titration..............................................................................................81
Free Chlorine, Amperometric Forward Titration....................................................................................................93
Total Chlorine, Amperometric Back Titration........................................................................................................99
Total Chlorine, Amperometric Forward Titration ................................................................................................105
Sulfite, Amperometric Back Titration .................................................................................................................. 111
Total Oxidants, “Quick” Two Step Amperometric Titration ................................................................................ 119
Chlorite, “Quick” Two Step Amperometric Titration...........................................................................................127
Manual Endpoint Determination ....................................................................................................................135
Below Detectable Limit ....................................................................................................................................137
Section 9 Maintenance ...........................................................................................................................139
9.1 Instrument Maintenance .................................................................................................................................139
9.1.1 General...................................................................................................................................................139
9.1.2 Display ...................................................................................................................................................139
9.1.3 Cleaning the Instrument.........................................................................................................................139
9.1.4 Cleaning and Conditioning the Electrode ..............................................................................................139
9.2 Maintenance Intervals.....................................................................................................................................140
9.3 Replacing the Fuse..........................................................................................................................................140
Section 10 Troubleshooting ....................................................................................................................141
Appendix A Amperometric Titration Theory..................................................................................145
1.1 General Titration Theory ................................................................................................................................145
1.1.1 Redox Reactions ....................................................................................................................................145
1.1.2 Reaction Measurement...........................................................................................................................145
1.1.2.1 Forward vs. Back .............................................................................................................145
1.1.3 Determining Concentration....................................................................................................................146
1.1.3.1 Conversion Factor ............................................................................................................146
1.1.3.2 Sample Spike ...................................................................................................................147
1.2 Errors and Interferences..................................................................................................................................147

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Page 4 50081_BookTOC.fm
1.2.1 Overview................................................................................................................................................147
1.2.2 Deposition on Electrode Surfaces..........................................................................................................147
1.2.3 Manganese Compounds .........................................................................................................................148
1.2.4 Nitrite Interference.................................................................................................................................148
1.2.5 Choice of Reductant...............................................................................................................................149
1.3 Errors Common to Total Chlorine Determinations.........................................................................................149
1.4 Shift of Endpoints Due to Sample Iodine Demand.........................................................................................151
1.5 Order of Reagent Addition .............................................................................................................................151
Appendix B Printer Installation and Setup......................................................................................153
Appendix C Replacement Parts & Accessories..............................................................................157
Appendix D Low Level Standards & Testing .................................................................................159
Appendix E AutoCAT 9000 Validation Study................................................................................161
General Information........................................................................................................................................167
Certification..........................................................................................................................................................169
How To Order ......................................................................................................................................................171
Repair Service......................................................................................................................................................172
Warranty ................................................................................................................................................................173

50081_Safety.fm Page 5
Safety Information
Please read this entire manual before unpacking, setting up, or operating this instrument.
Pay particular attention to all danger and caution statements. Failure to do so could result
in serious injury to the operator or damage to the equipment.
To ensure that the protection provided by this equipment is not impaired, do not
use or install this equipment in any manner other than that which is specified in this
manual.
Hazard Information
If multiple hazards exist, this manual will use the signal word (Danger, Caution, Note)
corresponding to the greatest hazard.
DANGER
Indicates a potentially or imminently hazardous situation which, if not avoided,
could result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation that may result in minor or moderate
injury.
NOTE
Information that requires special emphasis.
Precautionary Labels
Read all labels and tags attached to the instrument. Personal injury or damage to the
instrument could occur if not observed.
This symbol, when noted on the instrument, references this instruction manual for
operational and/or safety information.
This symbol, when noted on the product, identifies the location of a fuse or current
limiting device.
!

Page 6 50081_Safety.fm

Specifications
50081_Specifications.fm Page 7
Specifications
Specifications are subject to change without notice.
Methods
Titration methods 7 embedded methods
Titration stops Automatic and manual titration termination
Titrant addition technique Incremental
Titrant calibration 4 embedded procedures
Back titration with manual reductant addition
Measuring Ranges
Current ranges 2 µA, 20 µA, 200 µA, 1 mAmp
Temperature range –10 to +100 °C (14 to 212 °F)
Temperature resolution 0.1 °C (0.18 °F)
Printout
Automatic, GLP compliant
Selectable; OFF or 80 columns
Detailed or condensed
Graphic or no graphic
Results
QC check on results with visual warning
Statistical calculations
Units
All standard units for samples/results
Titration Curve
Up to 2000 points can be stored
Storage Capacity
Global password protection for programming access
Non-volatile memory
Storage of 200 titration results
Stored parameters characterized by own ID, location, and calibration data
Embedded operating procedures for electrode and reagent exchange
Automatic electrode, titrant calibration, and QC prompt
Sample List
Up to 126 data with alphanumeric ID
QC sample definition
Stirrer Platform
Magnetic stirrer 22 reproducible speeds (0 to 1100 rpm) in 50-rpm increments
Beaker volumes 5- to 400-mL

Specifications
Specifications
Page 8 50081_Specifications.fm
Burette
Embedded burette stand 1
Burette volume 5- or 10-mL
ISO/FDIS 8655-3 compliant
Burette step motor 18,000 steps
UV-protected encapsulated glass syringe
Embedded operating procedures Burette exchange, air bubble removal (Flush), Rinse, Fill, and
Empty functions
Inputs/Outputs
Electrode input
Temperature input
Serial connections for printer/PC
PS/2 port for PC keyboard
Language Options
English and Spanish
General Specifications
Casing Splashproof ABS plastic.
Graphic 128 x 128-dot LCD and alphanumeric keypad
Dimensions (H x W x D) 380 x 230 x 450 mm (15 x 9 x 17¾ inch) excluding tubing
Weight 5 kg (11 lb) excluding reagent bottles
CE marking EMC directive 89/336/EED Compliant
LV directive 73/23/EEC Compliant
Power requirements 50/60 Hz (±3 Hz)
100/240 V ac (±10%)
Pollution Degree II
Overvoltage Category II
Fuses Primary, User-serviceable. Slow-blow 1.0 A, 250 V
Secondary, factory-serviceable only.
Environmental operating conditions 5 to 40 °C (41 to 104 °F) temperature range
20 to 80% relative humidity range

50081_Introduction.fm Page 9
Section 1 Introduction
1.1 General Information
The AutoCAT 9000™ is an automated chlorine amperometric end point titration
instrument. Its biamperometric system uses a dual platinum electrode (DPE) probe.
Hach offers amperometric methods for determining total chlorine*, free chlorine, sulfite,
and chlorine dioxide in water. The chlorine dioxide procedure also provides a
measurement of chlorite concentration.
Follow the steps listed in Section 1.2, Instrument Startup Summary, on page 9. After
completing these steps, refer to the method calibrations and method procedures for
instructions on specific analyses.
Amperometric titration theory and interferences are detailed in Amperometric Titration
Theory on page 145.
1.2 Instrument Startup Summary
When you receive your AutoCAT 9000, proceed in the following order:
1. Unpack the instrument and inspect all parts for any damage that occurred during
shipment. Refer to Table 1 and Figure 1 and Figure 2 on page 24.
2. Assemble the instrument following the instructions in Section 2 on page 13
3. Review Basic Operation on page 23 to familiarize yourself with the user interface
and the keypad, navigation, and command keys.
4. Set the software parameters and configure the interface following the instructions
given in Section 4 Software Setup.
5. Clean and condition the electrode according to section 9.1.4 on page 139.
6. The instrument is set up and ready to perform analyses. The default titrant
concentration is adequate when using a fresh bottle of titrant but you may choose to
calibrate the titrant using the procedures given in Calibration Procedures on page 49
or you can download the exact concentration of your titrant, see Obtaining the
Certificate of Analysis for Hach Reagents on page 41.
7. At this time you may wish to run a few test samples to familiarize yourself with the
instrument. We recommend that you use tap water to perform the Total Chlorine
procedure in Titration Procedures on page 65.
8. If desired, you may choose to perform certain setup or configuration steps in Basic
Operation on page 23 but they are not essential for using the instrument.
*Forward and Back titration methods are offered for the determination of Total Chlorine.

Page 10 50081_Introduction.fm
1.3 Unpacking
Remove the instrument and accessories from the shipping cartons and inspect each item for
damage that may have occurred during shipment. Refer to Table 1 and Figure 1 on page 23 to
verify that your order is complete.
If any items are missing or damaged, please contact Hach Company or your sales
representative immediately.
Table 1 Packing List
Illustration
Item Number Catalog Number Qty. Product Description
Not shown 50083-00 1 AutoCAT 9000 AmperometricTitration Workstation
Not shown 18010-00 1 125 V ac power cord
1 — 1 Titrant pick-up tubing
2 50082-40 1 Delivery tubing with plastic anti-diffusion tip
3 — 1 Desiccant column
4 50087-00 1 Temperature sensor, glass, 103-mm, CINCH plug
5 50086-00 1 Metal electrode, dual platinum wire, BNC plug
6 50082-10 1 Burette stand, 5-mL, red cover
7 50082-50 1 Bottle stopper for 500 mL and 1000 mL plastic titrant bottles
8 50085-00 1 Magnetic stir bar
9 50082-60 1 Bottle stopper for 1-L glass titrant bottle
10 50088-00 1 Bottle holder
11 — 1 Stop ring for electrode head (may be pre-assembled)
12 — 1 Metal key for burette plunger adjustment
13 50082-30 1 Metal rod for electrode head support, 20-mm, with stop ring
14 50082-80 1 Bayonet electrode head macro, with support
15 50082-70 1 Fuse, slow-blow 1.0 A, (5 x 20 mm)
16 A25B600 1 Tubing from stopcock to glass cylinder
Not shown 500-46H 1 Beaker, 250-mL
Not shown 1999-53 1 Titrant, PAO standard solution, 0.00564 N, 1000-mL
Not shown 28341-00 1 KI SwifTest Dispenser
Not shown 1077-60 1 Refill vial for KI SwifTest Dispenser
Not shown 14909-32 1 Buffer, pH 4, 100-mL MDB
Not shown 21553-32 1 Buffer, pH 7, 100-mL MDB
Not shown 50081-18 1 User manual

50081_Introduction.fm Page 11
1.4 User Access Levels
The AutoCAT offers two user access levels:
Supervisor allows users to edit titration and analysis parameters to fit specific needs. A
Supervisor-level user can also assign a password to protect the data and customized settings
from inadvertent changes.
Routine allows users to access only the routine functions when performing the embedded
analyses.

Page 12 50081_Introduction.fm

50081_Assembly.fm Page 13
Section 2 Instrument Assembly
2.1 Operating Environment
Maintain an ambient temperature of 5–40 °C (40–104 °F) for proper instrument
operation. The relative humidity should be between 20 and 80%; do not allow moisture
to condense on the instrument.
Note: Retain the original packaging material. Instruments returned for service should be shipped
in the original packaging material to protect against damage during transportation.
Figure 1 Individual Parts (Refer to Table 1 for Part Descriptions)

Page 14 50081_Assembly.fm
Operating Environment
Figure 2 Assembled AutoCAT 9000
Legend
Number Item Name Number Item Name
1 Magnetic Stir Bar 11 Titrant Pick-up Tubing Connection
2 250-mL Beaker 12 Desiccant Column
3 Plastic Anti-diffusion Tip 13 Electrode (BNC Connector)
4 Temperature Sensor 14 Temperature Sensor (CINCH Connector)
5 Dual Platinum Electrode 15 Bottle Stopper for Plastic Titrant Bottle
6 Support Rod for Electrode Head 16 Pick-up Tubing
7 Burette 17 Bottle Holder
8 Plastic Anti-diffusion Tip Tubing Connection 18 Stop Ring for Electrode Head
9 Burette Tubing Connection 19 Electrode Head
10 Rotating Valve 20 Keyboard PS/2 Connector

Operating Environment
50081_Assembly.fm Page 15
2.2 Instrument Assembly
Perform the assembly procedures in this section and then complete the steps in Section 3on
page 23 to enter basic user information in preparation for performing analyses to comply with
Good Laboratory Practices (GLP). Refer to Section 4on page 33 for the software setup
required prior to performing analyses. The software setup in Section 4must be completed
before any analyses can be performed.
2.2.1 Attaching the Titrant Bottle Holder
2.2.2 Connecting the Electrode Head and Accessories
1. Slide the titrant bottle holder into the mounting slot located on the
bottom of the instrument housing.
2. Affix holder into position by compressing the bottle holder slightly and
inserting the tip into the hole located under the rim of the instrument
housing.
Note: Never pick up or carry the titrator by the bottle holder.
1. Thread the support rod onto the threaded stud of the stirrer platform.
Note: Never pick up or carry the titrator by the support rod.

Page 16 50081_Assembly.fm
Operating Environment
2.2.3 Connecting the Titrant Bottle
2. Clip the stop ring into the locating hole on the support rod.
Note: The stop ring may be pre-assembled on the support rod.
3. Compress the clips on each side of the electrode head and slide the
head onto the metal rod. Release the two clips to secure the head
in place.
4. Drop the supplied magnetic stir bar into the titration beaker and place
the beaker on the titration platform.
Note: The provided stir bar has been specifically selected for use with the
AutoCAT 9000. A different stir bar may spin erratically and produce
unwanted turbulence and added noise in the titration curve.
1. Place the titrant bottle into the bottle holder.
2. Thread the desiccant column onto the supplied bottle stopper.
3. Thread the appropriate bottle stopper (for 500 mL or 1000 mL titrant
bottle) onto the new titrant bottle and place it into the holder.

Operating Environment
50081_Assembly.fm Page 17
2.2.4 Assembling the Burette
4. Push the long section of exposed titrant pick-up tubing through the
remaining connection point on the bottle stopper and into the titrant
bottle. Thread the tubing connector into the bottle stopper.
5. Thread the opposite connector into the corresponding receptacle on the
rotating valve.
Note: Make sure that the tubing is connected to the correct point on the rotating
valve as indicated by the “bottle” icon.
6. The plastic anti-diffusion tip is pre-assembled onto the beaker supply
tubing. Thread the tubing connector into the corresponding receptacle
on the rotating valve.
7. Insert the plastic anti-diffusion tip into a small hole on the electrode
head. Turn the locking collar ¼-turn clockwise to lock it in place.
Note: Make sure that the tubing is connected to the correct point on the rotating
valve, indicated by the “beaker” icon.
1. Use the metal key to gently pull the piston plunger downward until it
protrudes slightly below the bottom of the burette.
Note: The bottom lip of the cylinder will offer only SLIGHT resistance. Do not pull
the plunger out completely. It it is inadvertently removed it may be carefully
pushed back into the cylinder. After reinsertion, closely monitor the
integrity of the seals after titrant is installed.
2. Place the burette on a flat surface and press the burette downward until
the piston shaft is flush with the bottom of the burette.
Note: Piston position is essential to proper instrument operation. Refer to the
illustration (left) for the correct position.
Piston
Travel

Page 18 50081_Assembly.fm
Operating Environment
2.2.5 Connecting the Temperature Sensor
3. Place the burette on the burette stand in position A then slide the
burette from position A to position B.
Note: Inspect the alignment of the
piston with the plunger shaft.
Ensure that they are properly
engaged as displayed in the
illustration to the right.
4. Turn the burette ¼-turn clockwise to engage the locking tabs with the
burette stand and lock the burette into position.
5. Thread the connectors of the remaining section of tubing into the top
of the burette and into the corresponding receptacle on the
rotating valve.
Note: Ensure that the tubing is connected to the correct point on the rotating
valve as indicated by the “burette” icon.
1. Remove the protective cap from the temperature sensor.
2. Insert the temperature sensor into a remaining small hole on the
electrode head.
3. Turn the sensor ¼-turn clockwise to lock the collar in place.
4. Connect the cable to the CINCH connector on the back of the
instrument (see Figure 3 on page 19).