LC/MS User Responsibilities
The LC/MS is a very powerful instrument, but routine maintenance is required to ensure high-quality data and minimize repair costs and downtime. The document below outlines the responsibilities of the Maintenance Representative (currently Diana) and the individual LC/MS users. All LC-specific items are applicable to both the 1100 and 1200 series instruments in our lab.
- LC/MS User Responsibilities (.pdf)
After using the MS, please disconnect it from the LC using the instructions in the document below. This will help avoid accidental damage to the MS by LC solvents.
The Prather Lab now owns a second HPLC that is shared with the Stephanopoulos Lab. The instrument is a newer version of the one in 66-425 and has a slightly different pump (binary vs. quaternary). See the "Reserving Time on the HPLC" section below to reserve time on the new instrument.
Transition to Single Column System
As of August 14, 2007 the HPLC is set up as a single column system to accomodate backflushing procedures for the Aminex column. This means that only one column can be installed at a time. The column connectors and flow direction are marked on the HPLC tubing.
With this new system configuration, ALL users will need to modify their methods as follows:
- Reconfigure the column/thermostat to 'Backflushing off' rather than simply 'Column 1' or 'Column 2'
- Set the thermostat for both sides of the heating block if your column straddles both of them.
- The new plumbing may cause the retention times of your peaks to shift, so you may want to consider constructing a new calibration curve
Aminex Column Updates
- The method AMINEXBACKFLUSH.M can be used to automatically backflush the column
- When running supernatants or samples containing salts using this method, run a blank every 10-15 samples
- The method's run time is 45 min
- This method should allow users to run > 15 samples without loss of resolution or the need to perform a manual backflush
- A guard column has been purchased specifically for the Aminex column
- Please use the guard to protect the analytical column and extend its life
- Install and remove the guard column and analytical column as a single unit
Column Installation & Storage Notes
Now that the HPLC is a single column system, it is important to be aware of what mobile phase is in the system before starting your analysis. Here are some guidelines that will help protect the integrity of the columns and your data.
- Before installing your column, flush the entire HPLC system with water with no column installed to remove the previous user's mobile phase
- When removing another user's column always cap the ends to prevent drying and store it in its original box
- If your column requires special storage conditions it is your responsibility to flush it with the appropriate storage buffer and remove it from the HPLC at the end of your reservation
A maintenance logbook is on the shelf above the HPLC in 66-425. Please record the date and a description of any maintenance you perfom.
Reserving Time on the HPLC
We currently use Google calendars to manage use of the HPLC instruments. To ensure that everyone has enough time to use the instruments, the HPLC usage policy is as follows:
Each user is allowed a total of 72 hrs per week (Sunday to Saturday) with a limit of 48 hrs per instrument.
You can access the reservation calendars by following the steps below:
- If you have a Google account, subscribe to the calendars by clicking on the appropriate link below:
- If you don't have a Google account, you can sign up for one using an existing email address by clicking here.
- Once you have a Google account and have subscribed to the calendars, email email@example.com with your Google username if you would like edit access. With edit access, you can use the calendars to reserve the HPLC.