Chromatography Forum

Hi Everyone,

I am in process of setting up my HPLC to run a sequence of samples overnight. There is just no feasible way to get all the samples I have done in regular working hours, so I thought I would give this a try to get caught up.

I have set up a sequence before when I was running my method validations, but I was also present when the samples were running. My question is...approximately how often would you run your standard in between sample runs?

Also, any tips or suggestions for overnight runs?

Thanks!

Redzilla

G'dy Redzilla,
My very strong suggestion would be to protect your HPLC with a good UPS, especially if your area is prone to power dips or failures - they always seem to happen 10 minutes after you have left for the night. There is a certain feeling of satisfaction when you arrive in the morning to process the overnight results and others are bemoaning lost data!

Neil

Hi

We use the following inhouse SOP:
inj 5 stds at the start of the run - %RSD n.m.t 2%
inj 2 stds in the middle of the run ,
inj 2 stds at the end of the run - %RSD of all 9 stds n.m.t 3%

When doing the "stability of solution' you will have a good idea of how long you stds and samples are stable for. When you have determined this you could put the following statement in you method of analysis " std and sample solutions are stable for ....hrs at room temp.

I how this helps
Mike

We inject standard a few times after about 12 to 20 samples (all injected twice or more).

Thanks everyone for your input. I'm going to do a shortened sequence while I'm here today, then get one set up for overnight tonight. Wish me luck!

Zilla