Chromatography Forum

hi

am using zic hilic - 2.1 x 150 mm, 3.5um column for analysing aminoglycosides in honey with lc ms detector. I use 5 ul as maximum injection volume as suggested by the column instruction sheet.

But now, as i need to get lower detection limits, am wondering if i can increase the injection volume to 10 ul. if i inject 10 ul, will it decrease the efficiency of the column or destroy it?.

any suggestions?

in HILIC we are dealing with hydrophilic compounds that are very soluble in water.
but the chromatography is done with mobile phase between 50-95% ACN
injecting "big" volumes of water in such a system changes the chromatography and bring bad separation and poor peak shape
but it will not kill the column
check how increasing the volume affects separation
see if you can increase the concentration of your sample, try to make a further dilution to a composition with your mobile phase

Hi
At one time, for Milichrom-4 recommenate this way.
Chosen mobile phase in which the matter had zero mobility and done in a row 10-50 entries. Sorbed substance in the beginning of the column.After that , made step gradient with mobile phase, that easily washes away the substance. Thus able to divide the sample up to 10 mg in column 2x64 mm.
In general, I recommend that you make the most concentrate aminoglycosides by concentrating SCX cartridges.

For support on the ZIC-HILIC column mail to

Support@sequant.com

or

Chromatography@merck.de

If you inject in water/acetonitrile you should be OK (no buffer), if you are using Ishii´s method
Food Add.Contam. A. 25 (2008) 1509-1519

@unmgvar.. i tried higher inj volumes and it didnt affect separation. so i suppose its ok with my analytes..

@dsp 007.. my idea is to avoid preconcentration step in the method.

@ Petrus..acutually am injecting in buffer alone (which is my mobile phase A), as it gives better sensitivity. anyways, i will write to the support ids u have given

thank u all for ur suggestions!