I having problem transfering a multiactive (4) dissolution gradient hplc method from Waters Alliance to HP1100. A: 50mM Acetate pH 4.5 B: MeOH
10-65%B in 25 min. 150 ul injection detection by UV 210nm. I gladly receive any help.

You did not specify what type of troubles you are having, but one of the problems may be a result of the difference in void volumes for the two systems. HPs is one of the shortest out there. The other thing that may be giving you trouble is the sensitivity differences with the two instruments - you may be overloading the HP system with a 150uL injection putting you outside the linear range of the method. Have you tried verifying the linearity and accuracy on the new system? You may find a small investigation of linearily and accuracy may target you problem.

Hope this helps

Without knowing what your your problem is this is more like fortune telling than troubleshooting. Assuming you are using on column concentration of aqueous samples and are having resolution related transfer problems, I think CLM was kind of on the right track. Stock Alliance and HP1100 systems have similar dwell volumes.

However a stock HP1100 cannot inject 150 microliters. Thus you must have installed either the multidraw kit or the 900 microliter syringe. If you installed the 900 microliter syringe this would have added over 1mL to your dwell volume (900ul loop + >150ul syringe cavity) and will change your gradient profile and could cause transfer problems, especially if you have peaks that elute early or late in the gradient.

System dwell volume is not the same as column void volume. In this case, if you have the 900 microliter injector, the added volume is all upstream of the sample slug and thus will not show up in the void volume. If you have a large volume seat capillary this volume will show up as increased column void (dead) volume. Let us know if this wasn't your problem. Good luck.

Thankyou Tom. You are good fortune teller. I no remember tell problem and you know answer. We know problem for long time and no find answer. Sorry for bad english. First 2 peaks come together with HP instrument. Have 900uL injector. How to know dwell volume. How to fix problem, need 900uL injector for another methods. No can change methods. Thankyou for good help.

Follow the attached link for a discussion on measuring the dwell volume.

http://www.lcresources.com/discus/messages/11/1717.html?FridayJune820010509am

Hope this helps,

Kevin

You can use the link above for a procedure for measuring dwell volume. I use water and 0.5% acetone in water.

You can try one or a combination of the following:
1) Injector program to delay the injection
2) Injector program to switch the injection valve to bypass after the sample has been swept onto the column.
3) Install the binary pump b/c it mixes on the high pressure side and has a lower dwell volume
4) Switch back and forth between the 100 and 900 microliter syringes as needed.

#4 will work for sure but it will require you to revalidate the system after each change. Switch syringe, leaktest, injector precision, injector linearity, and documentation. You could probably do this in a couple of hours after you have done it a couple of times.

Assuming you currently have a quaternary pump a combination of 3 and 1 or a combination of 3 and 2 will probably work.

#2 alone can work. The problem is you have to wait long enough to ensure that all of your sample is on the column (3-6 sample volumes), thus you don't really remove much dwell volume. Our lab uses both 100 and 900 microliter systems so when I develop a gradient method that I want to be able to run on either system I place a short isocratic hold at the begining of the method. This gives me time to load the sample and switch the 900uL systems to bypass.

See the injector manual for program steps, and depending on where you are your Agilent rep may be able to help.

Good Luck!

I have in the past tried transferring a method from a 2690 to an HP1100 and also had problems. We found it was related to the pump. i.e. the two systems were actually delivering slightly different compositions which led to slightly poorer resolution, which sounds similiar to your problem. Fortunately for us it was an isocratic method and we simply pre-mixed the mobile phase. No so simple for a gradient though. Sorry I can't offer a solution just a possible cause of the problem