As usual I was super stressed over the weekend over firmware upgrade issues. I was never IT savvy, let alone acquainted with computer terms. Firmware? Driver? Option pack? IP address?
On a happy note, my job breezed through today! Thanks to my readings and preparations over the weekend.
Plus the help of 2 crucial people, Mr C and Mr H.
And some luck. :)
Monday, December 15, 2014
Sunday, December 14, 2014
Maintenance #1: Column care and storage condition
I chanced upon some notes I got from a seminar from a long time ago, some column care procedure for sharing.
1. On backpressure
Always pump mobile phase from low flow, say 0.1ml/min then increase to normal flow rate.
Back pressure must typically be kept at <3500 psi (conventional HPLC columns and systems)
UPLC columns have higher pressure limits (more than or equal to 9000 psi)
In the event of high backpressure, reverse flush column.
2. On equilibrating column
Equilibrate column with mobile phase for 10-30 column volumes.
(Ion-pair containing mobile phase may require long to equilibrate.)
3. On sample preparation
Filter samples, 0.2um or 0.45 syringe filters, guard column
Sample cleanup, SPE, protein precipitation and so on.
3. On column storage
Never store columns with buffers, in long term.
Flush with 10 column volumes of mobile phase without buffer to remove buffer and salts.
Flush with 10 column volumes of mutually miscible solvent such as Methanol and ACN.
Flush with 20 column volumes of strong solvent, THF or IPA to remove strongly adsorbed sample components.
Reverse the process and equilibrate with mobile phase.
(Who has the time to do that?!)
Typical solvent storage conditions for silica-based columns:
Reverse phase: ACN/Water (65:35)
Normal phase: IPA or hexane
Ion-exchange: Methanol
SEC or Diol: 0.05% NaN3 in Water or 10% Methanol
With good column care maintenance, you can
- extend column lifetimes
- ensure optimal column performance
- minimizes downtime!
Till next time.
1. On backpressure
Always pump mobile phase from low flow, say 0.1ml/min then increase to normal flow rate.
Back pressure must typically be kept at <3500 psi (conventional HPLC columns and systems)
UPLC columns have higher pressure limits (more than or equal to 9000 psi)
In the event of high backpressure, reverse flush column.
2. On equilibrating column
Equilibrate column with mobile phase for 10-30 column volumes.
(Ion-pair containing mobile phase may require long to equilibrate.)
3. On sample preparation
Filter samples, 0.2um or 0.45 syringe filters, guard column
Sample cleanup, SPE, protein precipitation and so on.
3. On column storage
Never store columns with buffers, in long term.
Flush with 10 column volumes of mobile phase without buffer to remove buffer and salts.
Flush with 10 column volumes of mutually miscible solvent such as Methanol and ACN.
Flush with 20 column volumes of strong solvent, THF or IPA to remove strongly adsorbed sample components.
Reverse the process and equilibrate with mobile phase.
(Who has the time to do that?!)
Typical solvent storage conditions for silica-based columns:
Reverse phase: ACN/Water (65:35)
Normal phase: IPA or hexane
Ion-exchange: Methanol
SEC or Diol: 0.05% NaN3 in Water or 10% Methanol
With good column care maintenance, you can
- extend column lifetimes
- ensure optimal column performance
- minimizes downtime!
Till next time.
Thursday, December 11, 2014
Stress is an understatement
I came to a realization.
As a field service engineer, you basically have to say goodbye to life.
Tons of readings after work to handle odd complaints.
What seemed perfectly normal to me is deemed as instrument failure to user.
Too paranoid.
How can I better convince customers otherwise?
As a field service engineer, you basically have to say goodbye to life.
Tons of readings after work to handle odd complaints.
What seemed perfectly normal to me is deemed as instrument failure to user.
Too paranoid.
How can I better convince customers otherwise?
Sunday, December 7, 2014
Thursday, December 4, 2014
Troubleshooting #1: Plunger homing fault (1)
I performed a PM today and an error pops out when I attempted to reboot the instrument. And I saw "Plunger homing fault (1)".
The instrument worked fine before I started the PM. Checked the history and darn. Some related errors reported before... Basically the instrument could not restart, and hanged during initialization. Can't even do a dry/wet prime or anything.
I was reluctant to replace the torpedo because we had a really tight timeline this week. The torpedo needs a few hours to replace, together with some diagnostic tests. Error suggests the motor drive may have some internal problem. Could also have been other problems like the cable (shorting), encoder or PCB, or the fuse blown. Anyway... After rebooting the instrument a few times, I was losing hope.
I decided to give it one last try. To the solvent delivery system, please 'see' the home position of the plunger! Shook the torpedo a little. Maybe it helps. Maybe something was stuck or dislodged, and needed a little knock. Maybe...
"Initializing needle and syringe..."
"Initializing carousel..."
.
.
"Idle" (!) It worked!
Let's do a wet prime and run a flow. ...Plungers working fine!
Couldn't believe it. Let's try restarting the system, again. No more plunger homing error.
Amazed that problem was fixed by just shaking it. Sounds stupid, but it worked. Plausible that something was out of alignment, and shaking it brought it back to its rightful position.
Moral of the story: Don't be too quick to jump into conclusion. I almost wasted 4-5 hours. It's a lucky day.
Update March 2017.
Since I've been getting a lot more views on this topic, I will add more information to it.
What users do:
Loosen the inline filter before restarting the instrument
Inline filter of the pump is where all the particles are accumulated at, there could have been too much particles that it is blocking the movement of the plungers, from returning to its home position.
The instrument worked fine before I started the PM. Checked the history and darn. Some related errors reported before... Basically the instrument could not restart, and hanged during initialization. Can't even do a dry/wet prime or anything.
I was reluctant to replace the torpedo because we had a really tight timeline this week. The torpedo needs a few hours to replace, together with some diagnostic tests. Error suggests the motor drive may have some internal problem. Could also have been other problems like the cable (shorting), encoder or PCB, or the fuse blown. Anyway... After rebooting the instrument a few times, I was losing hope.
I decided to give it one last try. To the solvent delivery system, please 'see' the home position of the plunger! Shook the torpedo a little. Maybe it helps. Maybe something was stuck or dislodged, and needed a little knock. Maybe...
"Initializing needle and syringe..."
"Initializing carousel..."
.
.
"Idle" (!) It worked!
Let's do a wet prime and run a flow. ...Plungers working fine!
Couldn't believe it. Let's try restarting the system, again. No more plunger homing error.
Amazed that problem was fixed by just shaking it. Sounds stupid, but it worked. Plausible that something was out of alignment, and shaking it brought it back to its rightful position.
Moral of the story: Don't be too quick to jump into conclusion. I almost wasted 4-5 hours. It's a lucky day.
Update March 2017.
Since I've been getting a lot more views on this topic, I will add more information to it.
What users do:
Loosen the inline filter before restarting the instrument
Inline filter of the pump is where all the particles are accumulated at, there could have been too much particles that it is blocking the movement of the plungers, from returning to its home position.
Wednesday, December 3, 2014
Hard truths
Like any other employees, what we value most in a job are, job satisfaction, environment, people, learning curve.
But from industry's point of view, nobody gives a damn about your learning process.
As long as you can't produce result, you're in for deep trouble.
And nobody cares about how overwhelmed you are.
The tears and sweat you put in.
Everyone is just jumping into meaningless conclusions, I wonder if there is anyone who is truly neutral about this situation.
The last thing we need is to put people down, we really should help each other to drive this issue forward.
I don't know what's gonna happen to this person. But I foresee the same thing might happen to me in the next few years or so.
But from industry's point of view, nobody gives a damn about your learning process.
As long as you can't produce result, you're in for deep trouble.
And nobody cares about how overwhelmed you are.
The tears and sweat you put in.
Everyone is just jumping into meaningless conclusions, I wonder if there is anyone who is truly neutral about this situation.
The last thing we need is to put people down, we really should help each other to drive this issue forward.
I don't know what's gonna happen to this person. But I foresee the same thing might happen to me in the next few years or so.
Tuesday, December 2, 2014
Thought of the day
There is always something to learn from everyone (okay, not always but most of the time). If you think it is not worth doing it, then you're missing on a great chance to learn.
Subscribe to:
Posts (Atom)