HPLC water

[Ammu]

Can deionised water after passing through MIllIPORE can be used for HPLC. Does deionised water still contains organic impurities after passing through MILLIPORE that can interfere with chromatographic operation.

Ammu

[Narendra]

Normally distilled water suppose to be used for deionised through Milipore. Distilled water already free from organic impurities. Low and High boiling organic impurities should not be present in any purified water. Even it is present than you have to change the source of water.

From Narendra - India - Mumbai

[Ammu]

Thanx for your reply

now this deionised water after passing through millipore still contains organic impurities...

If i use this prepared HPLC water for analysis by isocratic mode...will their be a peak due to organic impurities and will the pressure rise up.


What is RO water prepared by MILLIPORE apparatus...is it single distilled...and can it be used to prepare HPLC water through MILLIPORE?

what is HPLC water exactly?

How does MILLIPORE works to prepare HPLC water?


Ammu

[DR]

What is RO water prepared by MILLIPORE apparatus...is it single distilled...and can it be used to prepare HPLC water through MILLIPORE?

RO water is water that has been pushed through a Reverse Osmosis membrane. This process removes the majority of organic impurities and most of the stray ions not caught by (typically) a resin bed pretreatment system. It can be used to feed a Millipore or other water purification system.

what is HPLC water exactly?

HPLC water is water that meets the needs of a HPLC system. For gradient analyses at lower UV wavelengths, it should have very low organic content (<3ppb) and very high resistivity (>18 M-ohm-CM).

How does MILLIPORE works to prepare HPLC water?

They, and other vendors, all use a closed loop system with a recirculating pump anad a variety of cartriges, filters and UV lamps depending on what exactly you want to do with the water you would have their systems produce. Flow diagrams and descriptions of the cartriges & filters are available at their websites. I'd check www.millipore.com, http://www.usfilter.com/water/, and http://www.barnsteadthermolyne.com/index.cfm?f=0

[MG]

In an isocratic separation, you would not see a peak from impurities in your mobile phase. But in a gradient separation, you might.

[Ammu]

Thanx for your reply all.

Hey DR can i use this RO water.... made through MILLIPORE apparatus and then passed through another MILLIPORE apparatus meant for making HPLC grade water ...For my isocratic HPLC analysis.


hey MG i don't know why i get a ghost peak apart from solvent and analyte peak sometimes. I tried all measures, changed my solvent, dilution tubes, analyte sample, finally i thought of contamination in water.

i had been using deionised water passed through MILLIPORE apparatus for HPLC grade water. can the organic impurities in this deionised water be the cause of GHOST peak in isocratic analysis.

or there could be possibility of remnants in detector cell of previous analysis. As the ghost peak appears in separate days ...though i had been using same HPLC water made from deionised water for my analysis.


regards

Ammu

[khimik]

FYI: It is possible, although rare, to see a mobile-phase impurity in isocratic separation. In order to see it, the following must be true:

1 The impurity is absent from what you're injecting, or present at a lower concentration;
2 The impurity absorbs more weakly at the wavelength you're using than the mobile phase as a whole.

It's a counterintuitive but textbook phenomenon, sometimes call an absence peak. Also, if the impurity absorbs more strongly than the mobile phase as a whole, the peak would be negative.

If your samples are prepared in mobile phase, you'll never see an absence peak, except in extreme exceptional cases I won't go into. Good reason to use mobile phase as diluent when possible.

[carey53095]

Hello -

I have a Labconco water purifier - and I see differences in samples prepared in purchased HPLC-grade water compared to samples prepared in my Labconco water (the unit is supposed to produce HPLC-grade water). Being a bit lazy, I use purchased HPLC-grade water exclusively. Hope this helps you - best wishes!