TA Instruments Nano ITC Series, Getting Started Manual

Page: 25 / 46

Nano ITC Getting Started Guide Page 25
3 Wipe the needle with a tissue and then screw the syringe completely into the buret drive.
NOTE : Before inserting the syringe into the buret drive, verify that the plunger indicator on the graduated
handle is in the fully raised position. Otherwise, mount the buret on the Nano ITC without a syringe and
click the
Buret up icon (green arrow pointing upwards).
4 Insert the syringe and buret drive into the Nano ITC.
5 Turn on the stirrer at 250 rpm and allow the system to re-equilibrate until the heat reading on the
calorimeter is stable.Then begin the experiment. Enter a file name at the prompt.
The results should be similar to those shown in the figure below.
Figure 9 Example of successful calibration.
Note that each peak has the same area except for the first. Typically the first injection shows less heat than
expected. This is often due to diffusion across the tip of the needle or to differences in positioning the buret
drive. For 5 µL injections of 1.00 mM HCl at 25°C, the expected heat is 237 µJ. The protonation enthalpy
in J/mol at any temperature between 5 and 50°C is given as:
∆
H
protonation
= -49659 + 102.28T - 0.59275T
2
The calibration factor (C.F.) is calculated as follows:
C.F. = (Expected Heat / Measured Heat) x Existing Calibration Factor