Day 11 - GC-ECD and more

I arrived at the lab at 7:45AM and left at 5:30PM. My day was spent entirely on the GC-ECD with Anna, while Adama and Marie worked on completing the 5^th batch of PSD extractions. Anna and I discussed how to run samples on the instrument and how to compose sequences. We agreed to run analytical sequences as : instrument blank (IB), continuing calibration verification (CCV), 8-10 samples, closing CCV, and IB; the 8-10 samples include field, trip and reagent blanks. I also introduced Anna to the idea of real-time Quality Control (QC) and got her acquainted with how to fill out and organize chromatography bench sheets. I had her calculate all QC limits (i.e. internal standard area counts, surrogate standard recoveries, and CCV passing limits). 

Unexpectedly, I spent a lot of time instructing Anna on how to integrate peaks, where to set integration baselines, and how to actually interpret chromatographic data. I suggested a workflow similar to OSU chemists, she adopted it, and it seems to be working well so far. To this end, I had her explain these concepts back to me as a demonstration of knowledge retention. Anna and I were able to complete the analysis of an IB, CCV, and 3 types of QC blanks over the course of the day. 

At least one, and no more than four, positive hits were identified in all reagent, trip, and field blanks with levels generally being less than 40 ppb. Overlaying these chromatograms revealed that the chromatographic profiles were quite similar between these samples with differences being mainly in peak amplitude. At first glance, background peak patterns appear to be systematic. The remainder of this sequence is running overnight and will be evaluated tomorrow. Completed data files are currently being saved as CSV files along with a snapshot of the final processed chromatogram.  

It was reported that we have one or two more extraction batches until all PSDs have been extracted. However, CERES staff will not be extracting tomorrow because the lab ran out of acetone; a solvent used in the cleaning of glassware. Additionally, the lab is not well stocked with pens. This results in an unneceesary amount of time being spent hunting for supplied within the laboratory.