Further analysis of current data

Over the past few weeks, I learned more about how to use the mass spectrometer properly. At first I learned how to use the basic functions of the instrument.  Then I learned that when the data looks skewed, I have to search for what I was doing incorrectly. In order to do so, I have to adjust the collision energy as well as the isolation width in order to see certain fragments. Through several trials, I discovered that contamination appears in single MS and not in tandem.  In cases where we find two peaks from the monomer and the fragments, we add analytes to our data.

Learning how to analyze data

The grad student in my lab taught me how to analyze the dissociation of dimers more closely and reasons for our specific experiment. After tuning, I try to adjust the collision energy in order to find certain peaks at a higher ion count. I learned that when I see homodimers form, then the solution at question is dimerizing. I also learned that fragmentation is essential as the solution breaks up, all the fragments should add up to the original compound. Also, if we chose to analyze only two of the fragments, then we would have to look at those two fragments for each dimer. Furthermore, she informed me that compounds that form intramolecular hydrogen bonded rings are satisfied as they are so they do not like to form dimers.

Reading about Mass Spectrometry

During the days of waiting for the mass spectrometer to be fixed, I learned a lot about the purposes for our experiment. Upon reading several articles, I learned that finding the proton affinity of different compounds is crucial as it is one of the most fundamental  properties in chemistry. In addition, dimerizing is a form of non-covalent bonding of two compounds through a hydrogen bond. We only use references that have one basic site so that we know where they protonate. In order to find the relative proton affinity of our analytes, we must know the absolute proton affinity for our references.  These are usually obtained using the equilibrium method.  In my reading, I learned the many different ways to measure proton affinities including equilibrium, the kinetic method, and the bracketing method. As our analytes are non-volatile, we are forced to use the kinetic method.

Third of Week of Being an Ion Thermochemist

The first week of lab, we did our annual cleaning as well as inventory. The following week, we were taught the different uses for mass spectrometers and their purposes. Emphasis was put on learning the theory behind the applications we undertake. Specifically, in relation to estimating chemical properties of a given compound. This week in lab,  I spent time learning how to find certain reference compounds that could be  a match for a specific analyte. Once I had established a list of possible references, I made dimers of each reference with the analyte in question. Afterwards, we ran the dimer solution through the ion trap mass spectrometer in order to analyze ability of each reference to dimerize with the analyte. I’m hoping to collect a list of viable references for each analyte in question in order to experimentally estimate the analyte’s chemical properties.

Kinetic Method

Hi! My name is Denise Lee and I am a sophomore. My major is chemistry. I am very interested in physical chemistry and have been conducting research under the supervision of Professor Poutsma whose research involves physical chemistry.

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