Issues with the HPLC

Vocab

PDA- (Photodiode Array Detector)- linear array of discrete photodiodes on an integrated circuit; allows a range of wavelengths to be detected simultaneously; yes the initials don't match the full word, I don't know why

Suspension- heterogenous fluid containing solid particles large enough for sedimentation

Centrifuge- piece of equipment that spins an object on a rotating axis; causes more dense substances to separate along the radial direction

Wednesday 3/9

I came in a little nervous today. I was supposed to find an HPLC-PDA method yesterday and I looked as hard as I could but I couldn't find one. I got there early so I could search a little more. After half an hour of frantic article-scanning Pablo came into the lab and asked what I was doing. He then told me that they found a method yesterday and it's working just fine. I was relieved and disappointed at the same time. It was a good lesson learned though. Searching through journal articles for specific ideas takes much more than an hour or two and you have to be completely focused. Next, we went up to Dr. Helferich's lab to look at the HPLC results. Unfortunately,some of the replicates were skewed so we repeated a few of the samples to see if it was merely human error. I weighed out the samples into tubes, added metaphophoric/formic acid for suspension and saponified for 15 minutes. Next, the sample was brought into suspension in the macrocentrifuge for 20 minutes. The sample was then extracted with my refined pipetting skills and centrifuged for another 20 minutes. As you can see this required a lot of waiting around. Luckily, Pablo has a lot of fun stories about feeding little kids in Honduras, living in India for the past year, and attending a military high school so I was entertained.