The End of the Line

This week was my final week of research this summer. I was very busy all week trying to get as much done as I could before I had to leave. On Monday I reran the DLS for the new cleaned DNANP samples and saw the same dramatic increase in size following cleaning. We still do not know why this phenomenon is occurring in the new samples but was not seen the original (10 ug/mL) sample. There are not any obvious signs of too much aggregation in the salt-TE cleaned samples so it is unclear why the phenomenon is occurring at all.

Then I ran ICP-OES on 10x and 1x dilutions of the supernatant and DNANP samples. A preliminary look at the ICP data revealed that the phosphorous concentration (2 phosphorus=1bp of DNA) was far below the detection limit even in the 1x sample. I then concentrated the remaining 10 ug/mL DNANP sample by 8x in order to hopefully get at least one measurement with detectable phosphorous. Even with the increased concentration the phosphorous was still undetectable. I will likely need to start from the beginning with a lot more sample so that I can concentrate the final sample by a larger factor but I will not be able to try that until the fall. With the remaining time this week I made and ran a new ICP calibration that covered sodium concentrations less than .500 ppm. This was applied to my water washed samples to hopefully determine whether any significant amount of sodium remained bound to the DNANP complex. I also reran the 10x and 1x dilutions to get more data. Today I have been working on compiling and analysing the data from the ICP. There seems to be a great deal of fluctuation and error in the ICP measurements which is concerning.