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June 06-07, 2019 | London, UK
2nd International Conference on
Tissue Science and Molecular Biology,
Stem Cells & Separation Techniques
Joint Event
Biomedical Research (An International Journal of Medical Sciences) | ISSN: 0976-1683 Volume 30
Exploring the effect of buffer strength on the retention time of weak acids, neutral
and weak bases in Hydrophilic Interaction Liquid Chromatography (HILIC) mode
Naser Al-Tannak, Sami Bawazeer and David G Watson
Kuwait University, Kuwait
Hydrophilic interaction liquid chromatography (HILIC)
orthogonal to conventional reversed phase high-
performance liquid chromatography (HPLC) mode allowing
separation of polar compounds, yet the separation
mechanisms reported in HILIC are much more complicated.
Therefore, this study was designed to investigate the effect
of water layer thickness on silica gel and the amount of
ammonium ions present within the buffer on HILIC retention
mechanism. Thus, a test system was designed which used
weak acids, neutrals and weak bases as probes with three
different strengths (5, 10 and 20 mM) of ammonium acetate,
formate and propionate as the counter-ions to compete with
the test probes with ionised silanol groups and water present
in the stationary phase. A Kromasil 60-5 SIL column (150
mm × 4.6 mm × 4 µm, pore size 60Å) was used as stationary
phase. As a result, retention times were examined for the test
probes at 90% acetonitrile (ACN) with 10% of 5, 10 and 20
mM of ammonium acetate, formate and propionate. As the
buffer strength increases, the thickness of the water layer on
the surface of the silica gel increases and also the repulsion
between ionized silanol groups and acidic test probes will
decrease. On the other hand, such increase in buffer strength
will increase the competition between the ammonium ions
and basic test probes. In conclusion, At 20mMbuffer strength
acidic probeswith low log P values retainmore due to reduced
repulsion by silanol groups. However, in 5 mMbuffer strength
basic probes with low log P value will be retained longer.
Speaker Biography
Naser Al-Tannak has completed his PhD at the age of 31 years from
Strathclyde University and postdoctoral studies from Strathclyde
Institute of Pharmacy & Biomedical Sciences, Strathclyde University,
United Kingdom. He is an assistant professor in Faculty of Pharmacy-
department of pharmaceutical Chemistry-Kuwait University. He has
published more than 12 papers in reputed journals.
e:
Naser Al-Tannak et al., Biomed Res, Volume 30
ISSN: 0976-1683