Last night Anna and I ran the I.S. and mix of PRC and 14 analytes so that we could update the calibration table retention times in Chemstation. At first glance the chromatograms looked great, but we are starting to lose a little resolution between some compounds...yet gaining some with others. The elution order and peak identification were hard to place a finger on with a few compounds near the middle of the run (Chlorpyrifos, Fipronil, PCB 100, Fenitrothion). The peak height ratios didn't really help much either. We found some standards in the freezer that had been previously used for other projects and did some dilutions and ran them for retention time. We are still sorting out two compounds. The back column was straight forward from the beginning. Also I am not seeing the breakdown in the inlet of compounds like I was before.
At the end of the day we realized that we were going to have a problem with pipeting 1 ml into or out of GC auto-sampler vials due to the pipet tip being too wide. After several email exchanges with Glenn and a Skype conversation with Paul we decided that we could just use the 1 and 2 ml graduations on the centrifuge tubes as volumes. This would simplify everything.
Overnight Anna and I ran on the GC 2 samples each of 1 mL of hexanes transferred using a 1 mL automated pipet and 1 mL hexanes transferred using graduations on a centrifuge tube and spiked all samples with the internal standard at 100 PPB. I wanted to know how accurate the centrifuge tube method was compared to the automated pipet method.
Adama, Marie, and Vieux arrived from St. Louis and performed the solvent cleaning of the 2nd retrieval samples. We will do the dialysis of these samples tomorrow. We will run the calibration standards on the GC tomorrow as well.
Friday, February 27, 2009
Week 5 - Wednesday
Sorry for the delay in posts, we've been working late and the internet at Hacienda had been down.
In the morning the staff (Adama, Anna, Marie, Vieux, and I) performed the sample blow down. That is, we used the Rotovaps and performed the nitrogen final blow down. The blow down took a very long time as only one rotovap can be used at a time due to the glassware compatibility problem I posted about before.
Some calibration standards and the internal standards were checked on the GC today.
We washed dishes today in preparation of the field samples from retrieval 2.
In the morning the staff (Adama, Anna, Marie, Vieux, and I) performed the sample blow down. That is, we used the Rotovaps and performed the nitrogen final blow down. The blow down took a very long time as only one rotovap can be used at a time due to the glassware compatibility problem I posted about before.
Some calibration standards and the internal standards were checked on the GC today.
We washed dishes today in preparation of the field samples from retrieval 2.
Wednesday, February 25, 2009
Week 5 - Tuesday
Update
Make serial dilutions of PRC and mix of analytes for calibration curve DONE
Make internal standard composite DONE
Solvent cleaning of field samples from the first retrieval DONE
Dialysis of first retrieval samples and QC DONE
Run practice samples on GC NO
Check some calibration standards on GC NO
Tuesday was a long day. The staff arrived at 8:00 am and we left at 7:00 pm. The decision was made to have Anna and I not go out to the field on Wednesday. We felt that we could use that time to train Vieux in the field and Anna and I could spend some much needed time on the GC. We got a lot done, but still have a lot of work ahead of us.
Make serial dilutions of PRC and mix of analytes for calibration curve DONE
Make internal standard composite DONE
Solvent cleaning of field samples from the first retrieval DONE
Dialysis of first retrieval samples and QC DONE
Run practice samples on GC NO
Check some calibration standards on GC NO
Tuesday was a long day. The staff arrived at 8:00 am and we left at 7:00 pm. The decision was made to have Anna and I not go out to the field on Wednesday. We felt that we could use that time to train Vieux in the field and Anna and I could spend some much needed time on the GC. We got a lot done, but still have a lot of work ahead of us.
Monday, February 23, 2009
Week 5 - Monday
This weeks outline
Monday - Create a blow-down module, do final blow down of practice samples, bake out glassware
Tuesday - Make serial dilutions of PRC and mix of analytes for calibration curve, make internal standard composite, log in samples, do solvent cleaning of field samples from the first retrieval, do dialysis of field samples and QC, run practice samples on GC, check some calibration standards on GC
Wednesday - Blow down samples, run calibration standards on GC, travel to St. Louis
Thursday - 2nd and final retrieval, travel back to Dakar
Friday - Log in samples, solvent cleaning of 2nd retrieval samples, run 1st retrieval samples on GC, clean glassware
Today Adama and I were able to create a blow down system (seen in picture below) that should work until a suitable replacement can be purchased (like a turbo-vap). We thoroughly cleaned all the parts of the new blow-down system we could. We tested the oven today and we found that the oven takes a long time to cool down. There is no exhaust fan, it is all internal. This will increase the time that the glassware will be unavailable to us as it is cooling. We can crack the door and get a decent rate of cool down, but when the oven shuts the heating coils off in the middle of the night it does not cool much before we arrive in the morning unfortunately. We started working on the paperwork for the standards to make tomorrow go faster.
On Friday I talked to Baba about getting the hood motors fixed since only one worked and it was underpowered. A technician came by today to check it out and told Baba, he would need to upgrade all the motors and replace them for the hoods to work effectively...I would agree. Also we had a guy come about the stainless steel counter-top and hood. He made measurements and can probably start this week. I think Baba said it would take about 2 to 3 days to complete when he starts. I believe it will be made with nice 1.5 mm stainless.
Monday - Create a blow-down module, do final blow down of practice samples, bake out glassware
Tuesday - Make serial dilutions of PRC and mix of analytes for calibration curve, make internal standard composite, log in samples, do solvent cleaning of field samples from the first retrieval, do dialysis of field samples and QC, run practice samples on GC, check some calibration standards on GC
Wednesday - Blow down samples, run calibration standards on GC, travel to St. Louis
Thursday - 2nd and final retrieval, travel back to Dakar
Friday - Log in samples, solvent cleaning of 2nd retrieval samples, run 1st retrieval samples on GC, clean glassware
Today Adama and I were able to create a blow down system (seen in picture below) that should work until a suitable replacement can be purchased (like a turbo-vap). We thoroughly cleaned all the parts of the new blow-down system we could. We tested the oven today and we found that the oven takes a long time to cool down. There is no exhaust fan, it is all internal. This will increase the time that the glassware will be unavailable to us as it is cooling. We can crack the door and get a decent rate of cool down, but when the oven shuts the heating coils off in the middle of the night it does not cool much before we arrive in the morning unfortunately. We started working on the paperwork for the standards to make tomorrow go faster.
On Friday I talked to Baba about getting the hood motors fixed since only one worked and it was underpowered. A technician came by today to check it out and told Baba, he would need to upgrade all the motors and replace them for the hoods to work effectively...I would agree. Also we had a guy come about the stainless steel counter-top and hood. He made measurements and can probably start this week. I think Baba said it would take about 2 to 3 days to complete when he starts. I believe it will be made with nice 1.5 mm stainless.
Week 4 - Friday
Today was a short day, I left at 2:00-ish, so did the rest of the staff.
The plan for today was to blow down our practice samples in preparation to run them on the GC. It became apparent that only certain parts of the N2 blow-down module (similar in function to the Anderson Lab's turbo-vap) worked properly. I was able to confirm with the staff that it had only kind of work as of late. Even with the functioning parts i don't think the flow through the 1/8 copper supply tubing would be sufficient for several simultaneous samples. I took apart the blow-down module to inspect it and can understand why it doesn't work very well. There is a design flaw and is needs new parts from the manufacturer to work correctly. We set in motion an idea to construct our own blow-down apparatus and will finish setting it up and testing it on Monday.
The blow-down via the roto-vap and transfer of samples was performed by me first followed by Adama, Marie, and Viex. Anna was present, but did not do/practice the transfer.
The plan for today was to blow down our practice samples in preparation to run them on the GC. It became apparent that only certain parts of the N2 blow-down module (similar in function to the Anderson Lab's turbo-vap) worked properly. I was able to confirm with the staff that it had only kind of work as of late. Even with the functioning parts i don't think the flow through the 1/8 copper supply tubing would be sufficient for several simultaneous samples. I took apart the blow-down module to inspect it and can understand why it doesn't work very well. There is a design flaw and is needs new parts from the manufacturer to work correctly. We set in motion an idea to construct our own blow-down apparatus and will finish setting it up and testing it on Monday.
The blow-down via the roto-vap and transfer of samples was performed by me first followed by Adama, Marie, and Viex. Anna was present, but did not do/practice the transfer.