Microcal VP-ITC USER MANUAL
MicroCal, LLC
22 Industrial Drive East
Binding Stability Kinetics support@microcalorimetry.com
Northampton, MA 01060 USA
Phone: +413 586 7720
Fax: +413 586 0149
VP-ITC MicroCalorimeter
User’s Manual
MAU130030 Rev. E
MicroCal, LLC VP-ITC MicroCalorimeter User’s Manual
Table Of Contents
General ............................................................................................................................................................i
How To Use This Manual ............................................................................................................................i
How to Get Help from MicroCal................................................................................................................ ii
Symbols..................................................................................................................................................... iii
Operators Safety...........................................................................................................................................iv
Product Safety................................................................................................................................................v
Instrument Specifications .............................................................................................................................v
Safety Specifications.....................................................................................................................................vi
European Users: CE Mark........................................................................................................................ vii
Instrument Safety Compliance.................................................................................................................. vii
Section 1: VP-ITC System Introduction.....................................................................................................1
1.1 VP ITC – The Basics...........................................................................................................................2
1.2 Data Acquisition and Instrument Control............................................................................................3
1.3 Suitable Laboratory Environment.........................................................................................................4
1.4 VP-ITC Parts and Accessories .............................................................................................................5
1.5 Setting Up the VP-ITC Instrument.......................................................................................................7
1.6 Pipette Assembly..................................................................................................................................9
1.7 The ThermoVac..................................................................................................................................11
Section 2: VPViewer and Origin Software...............................................................................................14
2.1 VPViewer and Origin Software Overview .........................................................................................15
2.2 Powering Up the VP-ITC Instrument..................................................................................................15
2.3 VPViewer Main Window...................................................................................................................17
2.4 ITC Controls Window........................................................................................................................21
2.5 Thermostat/Calibration Window ........................................................................................................26
2.6 Setup/Maintenance Window...............................................................................................................27
2.7 Constants Window..............................................................................................................................30
2.8 Real Time Data Display in Origin......................................................................................................31
2.9 ITC Cell Status ...................................................................................................................................34
Section 3: Running an ITC Experiment ...................................................................................................36
3.1 Designing ITC Experiments...............................................................................................................37
3.2 Using the ThermoVac to Degas Samples...........................................................................................41
3.3 Cell Loading.......................................................................................................................................43
3.4 Loading the Auto-Pipette....................................................................................................................44
3.5 Choosing The Run Parameters ...........................................................................................................47
3.6 Carrying Out Experimental Runs .......................................................................................................48
3.7 The Single Injection Method (SIM) ..................................................................................................49
3.8 Using the ThermoVac for Cleaning the ITC Sample Cell..................................................................51
3.9 Cleaning Syringes...............................................................................................................................53
Section 4: Experimental Tutorials ............................................................................................................54
4.1 Water-Water Baselines.......................................................................................................................55
4.2 Methanol Tutorial...............................................................................................................................64
4.3 Rnase-2’CMP Experiment Tutorial....................................................................................................67
Section 5: Instrument Maintenance...........................................................................................................68
5.1 Cleaning The Cells and Pipette ..........................................................................................................69
5.2 Replacing Pipette Plunger Tips ..........................................................................................................73
5.3 Y-axis Calibration ..............................................................................................................................77
5.4 Replacing Injection Syringes & Height Adjustment ..........................................................................79
5.5 Temperature Calibration.....................................................................................................................81
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Section 6: Tips and Troubleshooting ........................................................................................................85
6.1 User Tips and FAQs...........................................................................................................................86
6.2 Troubleshooting..................................................................................................................................87
6.3 A Note About Buffers ........................................................................................................................89
6.4 Selecting the Proper Stirring Rate ......................................................................................................90
6.5 Estimation of Required Concentrations..............................................................................................91
Section 7: Additional Features ...................................................................................................................92
7.1 Extended Data Display.......................................................................................................................93
7.2 Customizing VPViewer......................................................................................................................94
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MicroCal, LLC VP-ITC MicroCalorimeter User’s Manual
General
How to Use This Manual
This manual describes the VP-ITC; its setup, operation and maintenance.
Once the instrument is setup (as described in Section 1), a new user may wish to go directly to
Section 4 and run through the experimental tutorials for a “hands on” approach to learning about
the instrument and software. The user should then refer back to sections 2 and 3 for detailed
descriptions toward a better understanding of the intricacies of the instrument. Section 5 contains
important information for maintaining the instrument performance. Section 6 provides tips for
optimizing the performance and troubleshooting techniques for commonly encountered problems.
Section 7 provides description of some more advanced features.
Much of this manual provides descriptions of the VP-ITC instrument and software. Bullets or step
numbers are typically used when the user is requested to perform an operation.
• Indicates a step to perform an operation
1. Steps are numbered when the sequence of operations is critical.
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How to Get Help from MicroCal
The service department at MicroCal, LLC is available to help you during normal business hours, Monday
through Friday from 8:00 AM to 5:00 PM (EST). Service personnel may be contacted by e-mail, phone or
fax, with the preference being by phone or e-mail. When e-mailing MicroCal for technical assistance, if
possible, please attach a recent data file(s) (*.itc, raw ITC data files) that demonstrate the problem. Also,
please include with the correspondence, all details that may be relevant to the problem. In instances where
the problem or question relates to post run data analysis, it is best to attach the raw data file (*.ITC) and the
Origin document (*.opj) generated during data analysis.
There are 2 general categories of problems associated with the VP-ITC and its operation. The most extreme
category is when a system is simply not working, at all. Problems that prevent users from operating the
VP-ITC require immediate consultation with a MicroCal technician. Customers should not attempt to
repair the VP-ITC hardware or software unless instructed to do so by a MicroCal service
representative.
The second, and less extreme general category of problems is when a VP-ITC instrument is functioning, but
is not operating within its normal performance specifications. Large baseline drifting, non-repeatable control
peaks (Water/Water) and/or an increase in short term noise level are all examples of performance problems,
typically correctable by the operator. For performance issues such as these it is recommended that customers
carry out the following minimum diagnostic steps prior to contacting MicroCal for service:
1.) Thoroughly clean the cells. Do not assume they are clean. As a minimum, use the provided
Cell Cleaning Apparatus to pass 500 ml of a 10-25% ammoniated detergent in water solution,
followed by 500 ml of cold water rinse, through the sample cell. Discretion may call for a more
rigorous cleaning procedure as described herein.
2.) Refill both the reference and sample cells with filtered degassed water. Fill a thoroughly
cleaned syringe with water and/or use a different syringe.
3.) Go to the Setup/Maintenance window within VPViewer 2000 (as described, starting on page
27) and activate the extended data mode. (While in extended data mode, ITC data files will
contain all available information produced by the VP-ITC and often times is helpful in
diagnosis of problems).
4.) Carry out a minimum of 25, 10µL injections of water into water
5.) Consult the troubleshooting section of this manual.
If, after completion of the 5 steps listed above, the ITC performance is not corrected, contact the MicroCal
service department for help. The water run, in extended data mode, should be provided to the MicroCal
service technician for evaluation. The service department with comments and recommendations will then
contact customers.
MicroCal, LLC Contact Information:
Primary Contact Phone 413-586-7720
Toll Free Phone Number 800-633-3115
Facsimile 413-586-0149
Web Site: www.MicroCalorimetry.com
Please forward corrections or suggestions concerning this manual to info@MicroCalorimetry.com
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Symbols
Symbols used in this manual
! Warns the user of possible damage to the unit, draws attention to the risk of injury or
contains safety notes and warnings.
Symbols used on the VP-ITC instrument
Caution: Read the instruction manual before operating
Instrument (supply) ON
Instrument (supply) OFF
Protective Earth (Ground) Terminal
Origin® is a registered trademark of Origin Lab, Northampton, MA
VP is a registered trademark of MicroCal, LLC, Northampton, MA
MicroCal is a registered trademark of MicroCal, LLC, Northampton, MA
Windows™ is a registered trademark of Microsoft Corporation
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Operators Safety
! The points below are intended to enhance your safety awareness and to draw your attention to risks
which only you, the operator, can prevent. MicroCal has set high standards for ourselves in developing
and constructing the VP-ITC. Each unit constructed is fully tested to operational and safety standards.
It should be noted that no amount of design or constructed safeguards can anticipate or prevent improper
handling. It is intended that only responsible people trained in basic laboratory protocol in procedures
and safety techniques operate this instrument. This product is intended to operate from a power
source that does not apply more than 260 V rms between the supply conductors or between either
supply conductor and ground. A protective ground connection, by way of the grounding
conductor in the power cord, is essential for safe operation
! To avoid any hazard, use only a fuse of the correct type, voltage rating and current rating as
specified on the back of the VP-ITC. This is a 1 Amp 250 Volt Time-lag (Time Delay) fuse.
! Repairs, alterations or modifications must only be carried out by specialist personnel. The
MicroCal Service Department will be happy to serve you for any repair work or operational
questions.
! To enhance safety always plug the instrument into a Ground Fault Circuit Interrupter (GFCI)
device.
! A solution can become an electrical conductor when in contact with electricity and can create a
hazard with the potential of burns or death. Use caution when using solutions near the instrument
and adhere to the following items:
! If any liquid is spilled on or around the instrument unplug the instrument immediately
and wipe it up, if there is any possibility that some of the liquid may have leaked into
the instrument case contact MicroCal immediately. DO NOT PLUG THE
INSTRUMENT INTO ANY POWER MAINS, until the problem is resolved.
! Do not over fill the cell and reservoir. There is a small reservoir located at the top of
the access tubes to catch a minimum amount of overflow, do not exceed the capacity of
the reservoir
and allow any fluid to leak into the instrument cabinet.
! This device is not designed to the Medical Devices Directive 93/42/EEC and should not be used for
medical purposes and/or in the diagnosis of patients.
! When using volatile or hazardous solutions in the cells, the operator should always follow proper
laboratory procedures in handling (e.g. wear safety glasses and protective clothing) and disposing
of such materials and allow the internal cells to cool down to room temperature before removing
any solutions from the cells.
! All solutions in the cells must be cooled down below 50 ºC before removing from the cells to
prevent the glass syringes from breaking due to the hot liquids.
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Product Safety
We have used all means to design and produce the VP-ITC to prevent any damage to the instrument during
normal usage. The instrument is solidly built using the latest in micro-technology in its components and
design, but of course, this cannot prevent damage due to physical mistreatment. The attentiveness of the
operator to the identification of materials which could corrode the Hastelloy® Alloy C-276 cells, the
prevention of freezing solutions in the cells and the responsible handling and usage of the instrument should
ensure a long service life for the VP-ITC.
! The VP-ITC cells are constructed out of Hastelloy
corrosion by strong bases, but strong acids should be avoided. Please refer to the accompanying
booklet “Hastelloy
®
Alloy C-276” for further information.
®
C-276. Hastelloy is extremely resistant to
! The freezing of solutions in filled cells will cause irreparable damage to the cells due to the
expansion of the solution in the cells.
! When moving the VP-ITC the instrument should always be in its normal operating or its vertical
position. The instrument should never be moved in a sideways position, due to the nature of the
crystal detectors used for the instruments thermal sensing, which are strong in a compression
mode but weak when subjected to shear stresses.
Instrument Specifications
Model or Type : VP-ITC
Performance Specifications
Short Term Noise (RMS Average) : 0.5 nanocal/sec (2 nanowatts)A
Control Peak Repeatability : Mean ≤ 1.5µCal., s.d. ≤150 nCal B
Minimum Response Time (high gain) : 20 seconds
Operating Temperature Range : 2° to 80° C
Physical Specifications
Cell Material : Hastelloy® Alloy C-276
Dimensions (L x W x H in inches)
Cell : 17 x 8 x 15
Controller : 15½ x 16½ x 7½
Monitor : 9 x 15 x 15½
Weight (lbs)
Cell : 20
Controller : 25
Monitor : 12
A
For passive mode, using 3-min time intervals and 2 second filter for data points. This noise specification depends on AC power
fluctuations, and is stated here for stable AC voltage, which would be obtained using an isolated line or voltage regulator.
B
Mean energy for a series of thirty, 10 µl injections of water into water or buffer into buffer run isothermally at 30ºC, high gain
mode, stirring at 300 rpm
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Safety Specifications
Instrument Specifications (excluding Controller)
Electrical Specifications
Electrical Ratings:
Voltage : 110 - 240 Volts
Frequency : 50 / 60 Hz
Power : 70 watts
Fuses (2) : Primary=1.0 A, 250 V, Time Delay
Output : Secondary/Data Connection only
Protective Earth Terminals : Internal/external marked
Mode of Operation : Continuous
Classification : Class I
Atmospheric Specifications
Operating:
Temperature : 10° to 40° C
Humidity : 0 to 75% RH noncondensing
Atmospheric Pressure : 700 HPa to 1060 HPa
Storage: (in original shipping containers with no liquid in cells)
Temperature : -40° to +70° C (no liquid in cells)
Humidity : 10% to 90%
Atmospheric Pressure : 500 HPa to 1060 HPa
Cleaning the VP-ITC Instrument Case
Always shut down the computer controller and VP-ITC instrument and disconnect the mains power supply
cord before cleaning the case. To clean the instrument case, use a damp, lint-free cloth. Avoid abrasives or
solvents that can permanently damage the finish. With the damp cloth, gently wipe the external surfaces of
the instrument.
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European Users: CE Mark
MicroCal VP-ITC calorimeters carry the CE marking which confirms that they meet the applicable European
Community Technical Directives.
Following the provisions of the applicable European council directives:
89/336/EEC, 93/68/EEC Electromagnetic Compatibility
73/23/EEC, 93/68/EEC Low Voltage
Is in conformity with the following harmonized standards:
EN 61326-1:1997, A1:1998, A2:2001 Electrical equipment for measurement, control and laboratory use –
EN 61000-3-2:2000, A1:2001 Limits for harmonic currents emissions
EN 61000-3-3:1995 Limitation of voltage changes, fluctuations and flicker in low-
EN 61010-1:2001, IEC 61010-1:2001 Safety requirements for electrical equipment for measurement,
EN 61010-2-010:2003,
IEC 61010-2-010:2003
EMC requirements
voltage systems
control and laboratory use
Particular requirements for laboratory equipment for the heating of
materials
Instrument Safety Compliance
MicroCal VP-ITC calorimeters carry the CUE Safety Certification Mark,
authorized by TÜV America, a division of TÜV Süddeutschland, to signify that:
1) the instrument has been tested by an accredited Certification Body and meets
applicable Canadian electrical safety standards/requirements (CSA/SCC).
2) the instrument has been tested by an NRTL (Nationally Recognized Testing
Laboratory) and meets applicable United States electrical safety
standards/requirements (ANSI/UL).
3) the instrument has been tested by a Competent and Notified Body for applicable EU Directives
and meets applicable safety standards/requirements (EN/IEC).
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Section 1: VP-ITC System Introduction
This section starts by providing some basic information about the VP-ITC and the computer
controller. Then it provides instructions for setting up the VP-ITC instrument and accessories. It
ends by providing information about the ThermoVac instrument.
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1.1 VP ITC – The Basics
The VP-ITC (Isothermal Titration Calorimeter)
Unit directly measures heat evolved or absorbed
in liquid samples as a result of mixing precise
amounts of reactants. A spinning syringe is
utilized for injecting and subsequent mixing of
reactants. Spin rates are user selectable.
The normal operating range is 2°C to 80°C.
Wetted cell surfaces are Hastelloy® Alloy C 276.
Sample and reference cells are accessible for
filling and cleaning through the top of the unit.
The sample cell is on the right as one faces the
front of the unit.
A pair of identical coin shaped cells is enclosed
in an adiabatic Outer Shield (Jacket). Access
stems travel from the top exterior of the
instrument to the cells. Both the coin shaped
cells and the access stems are totally filled with
liquid during operation. This requires
approximately 1.8 ml. per cell even though the
working volume of the cell is only 1.4 ml
Temperature differences between the reference
cell and the sample cell are measured, calibrated
to power units and displayed to the user as well
as saved to disk. The data channel is referred to as the DP signal, or the differential power
between the reference cell and the sample cell. This signal is sometimes referred to as the
“feedback” power used to maintain temperature equilibrium. Calibration of this signal is obtained
electrically by administering a known quantity of power through a resistive heater element
located on the cell.
The syringe containing a “ligand” is titrated (injected) into the cell containing a solution of the
“macromolecule”. An injection which results in the evolution of heat (exothermic) within the
sample cell causes a negative change in the DP power since the heat evolved chemically provides
heat that the DP feedback is no longer required to provide. The opposite is true for endothermic
reactions. Since the DP has units of power, the time integral of the peak yields a measurement of
thermal energy, ∆H. This heat is released or absorbed in direct proportion to the amount of
binding that occurs. When the macromolecule in the cell becomes saturated with added ligand,
the heat signal diminishes until only the background heat of dilution is observed.
With the VP-ITC system the entire experiment takes place under computer control. The user
inputs the experimental parameters (temperature, number of injections, injection volumes) and
the computer carries out the experiment. Origin software is then used to analyze the ITC data
using fitting models to calculate reaction stoichiometry (n), binding constant (K
), enthalpy (∆H)
b
and entropy (∆S).
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1.2 Data Acquisition and Instrument Control
Two computer interface boards and a serial interface that reside inside the Computer Controller
operate the VP-ITC. The boards are pre-configured and calibrated at MicroCal, and need no
adjustments by the user.
Data acquisition is accomplished through a 16-bit A/D (analog to digital) converter board. There
are five differential inputs to the A/D, consisting of the DP or differential power between the
reference and sample cells, the Jacket Temperature, the DeltaT (temperature difference between
the cells and the adiabatic jacket), Shield Temperature (the outer shield temperature), and the
ATP channel (heat sink information). The default A/D inputs range from –1.25 volts to +1.25
volts for all input channels but can be changed through VPViewer. Additional available input
ranges are +/- 2.5 and +/- 5 volts.
ITC instrument control is accomplished through the second interface board, a 16-bit D/A (digital
to analog) converter board. Programmed by the VPViewer software, this board will regulate the
temperature of the VP-ITC, equilibrate the ITC in preparation for a titration run, and carry out the
ITC experiment.
The VP ITC injection system mounts on top of the cell unit and is controlled by VPViewer
through a standard RS-232 serial interface in the Computer Controller
Although other Windows’ programs can be used while the VP-ITC is running without affecting
the data acquisition or calorimeter control, it should be realized that there are real time operations
taking place during an experiment, and that performing CPU intensive tasks while an experiment
is in progress can ‘glitch’ the ITC baseline. Users are encouraged to avoid large file copying to
disk drives, large print jobs and recursive control loops while the VP-ITC is in the midst of an
injection run. Users can carry out routine data analysis while the VP-ITC is running.
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1.3 Suitable Laboratory Environment
The VP-ITC with Computer Controller requires about 1 meter of normal bench space (ca. 70 cm
wide). The ThermoVac degassing station will require another 25 cm length of bench space. This
location should be away from strong drafts, room temperature fluctuations, intense sunlight,
vibrations and strong electrical or magnetic fields (as may be produced by an NMR, microwave
oven, large motors or refrigeration units). In addition the mains power source (115 to 240 VAC)
should be properly grounded and free from voltage fluctuations, harmonic distortions, power dips
and spikes. The AC power line should be dedicated to the MicroCal system and should not share
that power with additional equipment.
Although, the power filtering in the VP-ITC instrument is adequate for most laboratory
environments, some disturbances may affect the performance of the instrument and it may be
necessary to have the AC Mains power source evaluated (see table below) or install a power
conditioner. Since power source problems can be manifested in many different ways, it is not
possible to recommend a power conditioner for all situations. It is recommended that you test a
power conditioner, at your location, before you purchase it. If you believe you are experiencing
power source related problems, please contact a MicroCal engineer.
VP-ITC AC Mains Requirements
Specification Requirement
Voltage Regulation
Frequency Stability
Power Line Noise
Harmonic Content
Ground Noise
Ground Quality
< 3% Common Mode or Differential Mode at any Frequency
< 2 VAC Ground to Neutral Peak-To-Peak at any Frequency
115 to 240 VAC, stable to ± 3%
0.5% Maximum Deviation
< 5% Total Harmonic Distortion to 1500 Hz
< 3% For any Single Frequency
< 1 VAC Peak-To-Peak
< 25 Ohm
It is emphasized that room temperature fluctuations (i.e. maximum 2.5° C) due to the cycling
on/off of heating and cooling systems, strong air currents, sunlight directly on the instrument and
through space electromagnetic waves may cause subtle performance problems.
VP-ITC Environmental (Operating) Requirements
Temperature
10° to 28° C, constant to 2.5° C
Humidity
Atmospheric Pressure
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0 to 75% Relative Humidity, non-condensing
70 HPa to 1060 HPa
MicroCal, LLC VP-ITC MicroCalorimeter User’s Manual
1.4 VP-ITC Parts and Accessories
In addition to the VP-ITC instrument, Computer Controller and connecting cables, there are
various accessories shipped with the VP-ITC for its normal operation. The parts and accessories
may include, but are not limited to the items listed below and on the next page. A list of the
actual parts and accessories shipped with your order will be listed in the documentation included
with your shipment.
Part Number QTY Description
ASS130010 1
ASS130140 1
ASS130150 1
INT100010 1
(call for part number) 1
SOF100040 1
SOF100025 1
ASS100030 1
ASS130070 1
(call for part number) 1
SYN161714 2
NDL130020 1
ASS130090 1
VP-ITC Cell
Pipette Stand
Injector/Stirrer Base (mounted on top of ITC cell unit)
Computer Controller
Printer (optional)
VPViewer software
Origin software
Main cable
Serial Cable with two 9 pin (RS232) adapters
A.C. Mains Power Cord
Hamilton 2.5ml filling syringes
18 guage, 8.5” long needle with Plastic syringe
Cleaning Device
ASS130120 1
ASS130330 1
ASS130370 1
TRY100010 1
MAU130010 1
MAU130020 1
MAU130030 1
Adapter (for Cleaning Device)
Shipping Cap
Temperature Standard (TC-2)
Accessory Tray
ITC Data Analysis in Origin Manual
Hastelloy Information Booklet
VP-ITC User’s Manual (this manual)
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VP-ITC Accessories in Wooden Box (KIT130010)
Icon Part Number QTY Description
TIP130020 9
ASS130360 1
Plunger Tips for Injection Syringe
250 µL Tip Sizer (Glass Bore with Green Cap)
BRU130010 1
ASS130170 1
DRI130010 1
DRI130020 1
ASS130210 1
ASS130230 1
Large Tube brush
Reference Plug Assembly
Hex driver (050”) for syringe clamps
Hex driver (7/64") for injector stand
Plastic Syringe Assembly (3cc) with tubing
Tube holder (white) for pipette stand
MSP13057 1
MSP13056 1
MSP13058 1
MSP13043 1
FUS100010 2
Plunger Tip Pusher tool
Plunger Tip Puller tool
Guide sleeve
Threaded Cap
Fuses (1A/250V, 5x20mm Slo-Blo Fuse)
WIR90006 1
.013 Cleaning wire injection syringe
ORG00005V
ORG00011V
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ORG00016V
PGR130010 1
ASS130160 1
ASS130200 1
MSP13028 1
SYA13022 3
Jar WITH 10 OF EACH OF:
1
005 O-Ring for Cleaning Device
011 O-Ring for Adapter & Syringe Holder
016 O-Ring for Syringe Holder
250 µl Plunger (for Cleaning Injection Syringe)
Pipette Injector
Syringe Holder (metal - pipette base)
Syringe clamp for bottom of injection syringe
Injection syringes
MicroCal, LLC VP-ITC MicroCalorimeter User’s Manual
1.5 Setting Up the VP-ITC Instrument
All VP-ITC and Computer Controller connections and setup must be done with the units
turned off and unplugged to avoid damage.
Components Required for Assembly
Computer Controller with CPU, Monitor, Keyboard, Mouse, Power Cord, (Printer is optional)
VP-ITC Instrument with flat Main Cable, Serial Cable with Adapters, Power Cord
(Please Note: The Pipette Assembly is described is section 1.6).
Setup the Computer Controller
• Set up the Computer Controller following the instructions that came with the computer. It is
advisable to ensure the computer is working properly before proceeding.
Connect the Flat Main Cable
One end of the Flat Main Cable has a 37 pin male connector (labeled ‘Cell’) that attaches to the
rear of the VP-ITC cell. The other end of the cable has two 37-pin male that attach to the rear of
the computer. The connector labeled ‘J1’ is for the D/A (digital to analog) I/O (input-output)
computer board. The connector labeled ‘J2’ is for the A/D (analog to digital) I/O board.
(Note: The J2 connector cable will be slightly shorter than the J1 connector cable. Also, the 37
pin plugs are wider on one side than the other to allow the cable to fit in one direction only. If a
contortion of the cable appears necessary to accommodate the appropriate connections contact
MicroCal for assistance.)
• Connect each of the two Flat Main Cable connectors (labeled J1 & J2) to their appropriate 37
pin female connector at the rear of the host Computer Controller. (The connectors at the rear
of the Computer Controller will also be labeled J1 and J2.)
• Connect the main cable end labeled ‘CELL’ to the cell connector, located at the back of the
VP-ITC instrument (labeled 4, on the next page).
Connect the Serial Cable
The serial cable has two 9 pin serial connectors; one connector is female and the other is male.
The female end is to be attached to the serial port (Com 1 or Com A) of the Computer Controller.
The male end is to be attached to the serial plug on the back of the pipette controller/stirring base
on the VP-ITC. (Note: Failure to connect the sserial connectors correctly will prevent the VP-
ITC injection system from operating properly.)
• Connect the female end of the serial cable to the Computer Controller at the serial port.
• Connect the male end of the serial cable to the serial connector on the back of the pipette
controller/stirring base on the VP-ITC (connector labeled 6, on page 8).
(Note: Earlier versions of the VP-ITC require a slightly different serial cable and connection
sequence. Contact MicroCal for further information.)
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MicroCal, LLC VP-ITC MicroCalorimeter User’s Manual
Connect the Mains Power Cord
• Connect the power cord to the inlet power receptacle located on the back of the VP-ITC.
Connect the power plug only to a mains power supply receptacle with a 3 wire, protective
earth ground, plug and Ground Fault Circuit Interrupter (GFCI). Please Note: It is strongly
recommended that the VP-ITC be provided a dedicated AC power line with no other
equipment being powered on that line. (see page 4 for more information about selecting a
location for the instrument)
*
VP-ITC Cell - Back View
1) Main power switch
2) 2 Power fuses
3) IEC 320 inlet power receptacle
4) Cell connector
5) Fan
6) Pipette controller/stirring base serial port
7) Pipette controller connector
* Earlier versions of the VP-ITC Cell have a different connection configuration
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1.6 Pipette Assembly
The pipette assembly consists of the injection syringe with pre-mounted top syringe clamp, a
bottom syringe clamp, the syringe holder and the pipette injector.
! Caution: At all times when handling the injection syringe you want to use care to
prevent the long needle from any action that may cause it to bend. If the long needle is
bent far enough it will become a permanent bend that will make the syringe unusable
for any experiments.
! Caution: Never attempt to couple/decouple the pipette from the syringe assembly unless
the pipette plunger is in the open port position (all the way up). Failure to follow this
recommendation may result in a bend in the pipette screw. Even a slight bend will
result in improper operation of the pipette.
To assemble the pipette, please do the following (please refer to diagrams on next page):
The height must be adjusted for any syringe that was not part of the original shipment of your
VP-ITC instrument. Please refer to Section 5.4 Replacing Injection Syringes & Height
Adjustment (page 79) for instruction on adjusting the height of the syringe.
• Insert an injection syringe into the syringe holder until the top syringe clamp is firmly seated
against the top of the syringe holder. (see diagram next page)
• Insert the bottom syringe clamp over the syringe needle onto the glass part of the syringe.
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• Make sure the top syringe clamp is still seated against the top of the syringe holder, hold the
bottom syringe clamp tightly against the bottom of the syringe holder and gently tighten the
set screw using the accessory 0.050” Ball Point Hex Driver.
! Use care not to over tighten the set screw, as too much pressure will cause the glass to
break. You want to tighten the screw just enough to prevent the bottom syringe clamp
from moving freely.
• Insert the syringe holder into the pipette holder (attached to the
side of the VP-ITC).
• Bring the pipette injector directly above the syringe holder, start
bringing the injector down while observing the plunger tip of the
pipette injector to insure that it is being inserted into the hole in
the glass barrel of the injector syringe, then mate the screws of the
pipette injector to the locking collar of the syringe holder
• With your fingers, turn the locking collar until it is fully tightened
on the pipette injector.
When the locking collar is fully tightened there should be only a
couple threads of the pipette injector viewable.
• Plug the connector of the pipette into the back of the pipette
controller/stirring base (connector labeled 7, on page 8) to
complete the pipette assembly.
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1.7 The ThermoVac
ThermoVac Description
To facilitate degassing samples and cleaning the cells, you have been provided with the
ThermoVac accessory, a device for thermostatting and degassing samples. The unit is capable of
thermostatting a sample at any temperature from 0 to 80 °C, pulling a vacuum of 28.4 inches of
mercury and stirring the sample using small magnetic stir bars.
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ThermoVac Accessories
The ThermoVac and accessories may include, but are not limited to the items listed below. A list
of the actual items shipped with your order will be included in the documentation included with
your shipment.
Quantity Description
1 ThermoVac
3 Stir Bars (Small)
3 Stir Bars (Medium)
2 In-line filters
5 Test Tubes (Small) – for conserving sample volume
5 Test Tubes with Cap (Medium)
1 Test Tube Holder
1 Flask with Hose & Luer Lock Connector
2 Fuses (1A/250V) 5x20mm Slo-Blo
1 A.C. Mains Power Cord
Front Panel Controls
VACUUM
The ThermoVac is capable of pulling a maximum vacuum of 28.4 inches of
mercury. If the VACUUM switch is pushed to the right the vacuum pump
will turn on and remain on for approximately 5 minutes (recommended time
for degassing samples), then the pump will shut off. If you desire to remove
the vacuum before the preset time you must turn off the main power switch (located at the rear of
the instrument). When the switch is pushed to the left the vacuum pump will remain on until it is
manually turned off (either by pushing the VACUUM switch to its middle, OFF, position or by
turning off the main power switch).
TEMPERATURE
Use this dial to set the temperature, in °C, for thermostatting the sample chamber. The rightmost
digit sets the temperature value in tenths of a degree. Typically, ITC samples are thermostatted to
a temperature that is below the desired run temperature for the sample. This should also allow for
any temperature increase that may occur during the transfer of solution from the ThermoVac to
the ITC cells or syringe.
SAMPLE TEMPERATURE
Displays the current temperature of the sample chamber.
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STIRRER
This switch will activate a rotating magnetic field that will stir your sample when a small
magnetic stir bar is placed in the tube containing your sample. You may adjust the speed of the
Stirrer motor from 0 RPM (OFF) to the maximum speed of 800 RPM (full turn clockwise).
ADJUSTABLE VACUUM BLEEDER
Allows manual adjustment of the vacuum strength within the degassing chamber of the
ThermoVac.
There is no vacuum gauge on the ThermoVac, but the strength of the vacuum may need to be
adjusted based on the behavior of your samples under vacuum. Depending on the specific sample
being degassed, and on the temperature of the sample, the vacuum strength might be enough to
boil the sample and subsequently change the concentration and/or spill the sample. This may be
avoided by adjusting the strength of the vacuum with the bleeder screw. By turning the top of the
bleeder screw in the counter-clockwise direction you will lower the strength of the vacuum within
the ThermoVac and avoid boiling your sample. Similarly, the vacuum strength can be increased,
by turning the top of the bleeder screw in the clockwise direction. The bleeder screw (and
vacuum strength) can be fixed in a desirable position by tightening the lower nut, located at the
base of the bleeder screw assembly, all the way in the clockwise direction.
REAR PANEL
1. Power Main Switch
2. 2 Power Fuses
3. IEC Inlet Power Receptacle
4. Vacuum Port
5. Pressure Port
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Section 2: VPViewer and Origin Software
This section details the features of the VPViewer and Origin software. VPViewer provides the
user interface to control the VP-ITC instrument and conduct the experiment. Origin (in this
project window) is used only for plotting the data received from the VP-ITC instrument. A
separate project window for Origin (Origin for ITC) is used for analyzing data.
New users may find this section too detailed for their immediate needs and for that reason skip
this section and proceed to the Section 4 tutorials for a ‘hands on’ approach to learning the
software though simple experiments. While performing the tutorials, the user should refer to this
section when further detail is desired about a specific software function. After performing the
tutorials, it is advised to read through this entire section for a thorough understanding of the
software.
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2.1 VPViewer and Origin Software Overview
The VPViewer 2000 software controls the operation of the VP-ITC calorimeter. It is within
VPViewer 2000 that all ITC experimental parameters are entered, runs are controlled and data is
saved to the hard disk of the Computer Controller. By default, all data that is generated in the run
state of an ITC experiment will be saved to disk, with no user interaction.
When VPViewer 2000 is started it opens a linked copy of a project window in Origin, named
VPITCPlot.opj. This project window of Origin is strictly for real time display of data from
VPViewer and is not intended for data analysis or saving data; VPViewer automatically saves all
relevant experimental data.
Please note: If Origin is closed by accident, an error message will appear and the data display
will be lost until Origin is again reopened by utilizing the VPViewer 2000 menu, System|Open
Origin. VPViewer 2000 must be used to open up Origin for real-time display or the real-time
plotting will not work. As long as VPViewer remains open, the experiment will continue and all
data will still be automatically saved to disk independent of the real-time plotting.
Operation Within a Windows™ Environment
Only one copy of VPViewer will be permitted to run at any given time. If a second instance of
the application is detected, VPViewer will immediately terminate itself. Users should feel free to
run Origin
applications. In general, VPViewer is a multi-tasking application with some subtle limitations. If
VPViewer detects a conflict that may jeopardize its ability to acquire data, it will inform you of
this conflict. In such instances you should contact MicroCal.
for data analysis simultaneously with VPViewer, as well as most other Windows’
Although, other Windows’ programs can be used while the VP-ITC is running without affecting
the data acquisition or calorimetric control it should be realized that there are real time operations
taking place during a run, and that performing CPU intensive tasks while a run is in progress can
‘glitch’ the ITC baseline. Users should avoid large file copying to disk drives, large print jobs
and recursive control loops while the VP-ITC is in the midst of a run.
2.2 Powering Up the VP-ITC Instrument
The VP-ITC main power switch and the VPViewer software application can be left on
indefinitely. There may be occasions when the instrument is turned off and then turned back on.
Problems can arise if the recommended power up sequence is not followed. Whenever powering
up the VP-ITC, please follow the steps below in order:
1. Turn on the computer controller. The VP-ITC power switch must be off.
2. Once the computer controller is on and Windows is running, turn on the power
switch at the rear of the VP-ITC.
3. Launch the VPViewer application by double clicking its icon on
the Windows desktop or from the Windows taskbar by selecting
Start : P
Please note: Failure to adhere to this sequence when powering up the VP-ITC
may result in the injection system not responding.
rograms : MicroCal’s VPITC : VPViewer ITC.
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A Note About ITC Power Control
The main power for the VP-ITC cell unit is controlled by the VPViewer software application.
The presence or absence of power to the cell unit is indicated by the Power LED located on the
front panel of ITC cell. When the power to the cell unit is on, the LED will shine bright orange
and when the power to the cell unit is off, then the LED will also be off. In order for the cell unit
power to turn on, the cell must be plugged in, the power switch at the rear of the cell must be in
the on position, and VPViewer must be opened and running. Upon opening the VPViewer
application, it may take several seconds for the ITC cell power and the Power LED to come on.
Likewise, after closing VPViewer it will require a minute or so for the cell power and Power LED
to turn off.
When the VPViewer application is first opened it will go into an ‘Initialization’ state for less than
one minute, as will be indicated in the cell status. During the ‘Initialization’ state the VPVIewer
application is disabled and will not fully respond to mouse/keyboard events. As soon as the
‘Initialization’ state is over with, then the VPViewer application will become fully enabled and
the ITC injection system will be initialized as well.
The VP-ITC was designed to have its power on for extended periods of time. This will keep the
electronics at the normal operating temperature for better repeatability. It is recommended that
the power to the ITC cell unit be turned off during extended periods of down time, such as
holidays and vacations.
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2.3 VPViewer Main Window
When you launch VPViewer, the Main Window of VPViewer is displayed (as shown below).
VPViewer Data Channel Display
By default, VPViewer displays three data channels and the status of the instrument.
Instrument Status
In the above illustration, the instrument is Thermostatting (ITC) at 30 °C.
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Temp(Celsius)
This text box displays the current temperature, in degrees Celsius, of the adiabatic jacket.
DP (uCal/sec)
This text box displays the Differential Power, in µCal/sec., between the reference cell and the
sample cell. Positive DP values means that the reference cell is hotter than the sample cell, while
negative DP values means that the sample cell is hotter than the reference cell. In terms of
reactions (assuming they take place in the sample cell) exothermic reactions will cause the DP to
deflect in the negative direction while endothermic reactions will cause the DP to deflect in the
positive direction. The power units for the DP data channel may be displayed in mCal/min.,
µCal/sec. or µWatts. Experimental data will always be saved in units of µCal/sec.
Whenever the VP-ITC is equilibrated the DP value should be positive and stable. The power
level of the equilibrated DP signal should be close (+/- 1 µCal/sec.) to the ‘Reference Power’
setting, as set prior to starting the run.
DT (deg. C)
This text box displays the Differential Temperature, in degrees Celsius, between the adiabatic
jacket and the calorimeter cells (i.e. the average temperature of both cells).
Whenever the VP-ITC is equilibrated the DT signal should be close to zero degrees Celsius (+/-
0.05) and stable.
Menus and Buttons
The VPViewer Main Window contains drop down menus, buttons and Window Tabs. The Main
Drop Down Menu selections generally control global system functions The Main Window Buttons
allow easy access to features that are frequently used. The Main Window Tab Selections provide
detailed windows for specific functions. The details of these controls can be found in the
following sections.
VPViewer Main Drop Down Menus
The Main Drop Down Menus at the top of VPViewer will provide access to some of the less
frequently used functions of the application.
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