MicroCal PEAQ-ITC by Malvern Panalytical

"The device is easy to use. The small amount of substance to be analyzed is a big advantage. This is a great saving of money. It is a precision instrument with high sensitivity and accuracy. In one analysis we get all the thermodynamic parameters needed to develop inhibitors."

"Although I appreciate that the low-volume Peaq-ITC allows for rapid testing (~8 experiments per day on average) the overall use of the instrument is miserable. It will randomly disconnect from the computer every once in a while. Luckily this hasn't happened during an experiment, but is frustrating when you go to start an experiment and you have to shut down the computer to get the instrument to reconnect again. Furthermore, although the automatic cleaning is useful, it is the most frustrating aspect of the instrument. Too many parts and seals necessary. Most ridiculous is that you have to wait 7-9 minutes before the cleaning system will tell you there is an error with the cleaning, and will cancel. So you check the connections and restart, wait 7-9 minutes again for it to fail again. You then get tired of waiting for it to clean and do a ridiculous manual clean (there is no good way to do a manual clean), and there will be an error stating the instrument hasn't been cleaned in XX-uses. At the minimum there should be an override control of the cleaning system so experiments can continue. To top it off, the most frequent problem that causes this cleaning issue is part #: ASY5020090. A little tube with a connector and a little black seal for ~$300, which we have to replace every 3-4 months, as that is approximately how long we have until this little part fails and we can no longer utilize the instrument because it will not clean. The sensitivity is high on the instrument, which is good. However, when systems has low heat, the signal-to-noise ratio is very high and the baseline is terrible. This, in turn, makes you use more sample at a higher concentration, wholly defeating the purpose of this instrument. The error between experiments is about 2-3 times higher than the error between experiments on the VP-ITC as well, which is ridiculous. I need to do ~6-8 experiments to obtain the same error on 3 experiments by the VP-ITC. So basically you can do quicker experiments, but you need the same overall amount of time to get reasonable data. Lastly, the data analysis software is of poor quality. The switch to proprietary data analysis has made data analysis cumbersome, compared to the use of Origin as the fitting software. Two-Site fitting is backwards when binding site #1 is actually binding site #2. The fitting curve gets stuck when trying to fit two-site data, and requires extensive manual fitting to get it to work, with questionable results and thermodynamics. Although this is a small complaint, when making the isotherms publication quality, you have to use individual drop-downs for every little piece of the graph. The lines are not even black as the default, but a weird blue-grey color. Changing the raw data to black then the axis labels to black, then switching and changing the fitted data colors takes a ridiculous amount of time. Plus there appears to be ~100 color choices, which is just overkill."

"A very good instrument, however, the small volume of cell and syringe cannot meet the requirements of supramolecular chemistry well. Generally, the small volume can save reagents, but for some specific cases, it limits the application of PEAQ-ITC."

"The MicroCal PEAQ-ITC is a significant upgrade from the VP-ITC and ITC200 in terms of the ease of maintenance. All washing steps are now automated and easy to perform. We find this helps to keep the instrument in an excellent condition even with multiple users. Due to the somewhat complicated cleaning procedures of previous versions of the ITC we found that routine maintenance was not always performed which greatly affected results in this highly sensitive instrument. The PEAQ is still a low volume isothermal titration calorimeter ideal for label-free, in-solution studies of biomolecular interactions. Software upgrades have also made the PEAQ easy to use even for the most inexperienced scientists in the lab, including help in experimental planning and optimisation of parameters prior to performing any runs. We find the PEAQ really useful for confirming binding, measuring stoichiometry, protein QC, troubleshooting other biophysical methods and identifying different mechanisms of binding in closely related compounds."

"Excellent ease-of-use. Video training modules allow for users across disciplines to rapidly collect data."

"There is a higher upfront cost than with other ITCs, but the available nascent kinetics parameters and lower cost consumables make it a good investment in the longer term."