Stop by and scoop some cat litter or have some candy!
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Today, our doors are open to anyone who is interested in polymer analysis by MALDI-TOF MS.
Please stop by our Facility to learn more about our equipment and have a cup of coffee!
We are expecting a short interruption in our services on Wednesday, January 28 which will affect LCT and QTRAP customers (James). A longer interruption is expected for Orbitrap services (Tania): Wednesday through Friday, if all goes well. The OPP electricians will be installing a new circuit breaker in the main panel in our lab.
The sample preparation for MS (in-gel digestion) and MALDI TOF analyses will not be affected.
If anyone feels frozen, please come to 3 Althouse: it is a tropical paradise, about 90 F, so dress appropriately!
Joana’s sample is running. It takes 24 hrs of Orbi time to run 1 Joana’s sample: 3 blanks, 1 standard, 1 control, and 1 sample. All this to ensure that everything works as expected: the instrument, the sample prep, the chromatography. Talk about loving care…
Orbi is well and running Olga’s samples. Joana’s and Anna’s samples are digested.
This was a question from one of my blog’s secret readers. Actually, most of the time I feel like I am talking to myself: “Hey Tania, how do you prepare a protein sample for proteolysis?” “Well, Tania, let me show you in a step-by-step tutorial.” No comments, no questions, no pointing out typos, no “thank you, Tania, but there’s a better way to do this”?
Oh well, back to ammonium bicarbonate. This is a volatile salt which breaks down to ammonia, carbon dioxide, and water. Volatile salts are the only salts compatible with MS. Aqueous solutions of ammonium bicarbonate (0.01 – 0.1 M) have pH around 8, the optimal pH for trypsin activity. Ammonium bicarbonate competes with basic amino acids for Coomassie dye, which makes it a great de-staining reagent for the in-gel digestion procedure. All this goodness comes at a very reasonable price – what not to like? Another ammonium salt, triethylammonium bicarbonate (TEAB), is more volatile than ammonium bicarbonate; it is also more expensive. TEAB is a buffer of choice for LC-MS applications: TMT (iTRAQ) amine-reactive labeling, ion-exchange chromatography, protein solubilization (when neutral and acidic pH is undesirable), in-gel digestion, etc.