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M. Talebi et al.
SLB-IL59 column have similar polarities, but they showed complimentary selectivities for (Z)-β-ocimene and 1,8-cineole. All four test compounds were separated
with better resolution on the SLB-IL59 column compared to the 5% phenyl PDMS
column. Also, a big difference in the elution order was observed on the two phases;
on 5% phenyl PDMS, the elution order was p-cymene < limonene < (Z)-β-ocimene
< 1,8-cineole, while on SLB-IL59 the order was limonene < (Z)-β-ocimene < 1,8cineole < p-cymene. Peak symmetry and capacity factors (k) of the IL and wax
columns were evaluated by using different test compounds representing a specific
class of compounds: limonene for monoterpene hydrocarbons, linalool for monoterpene alcohols, (E)-caryophyllene for sesquiterpene hydrocarbons, neral and geranial
for monoterpene aldehydes, and neryl acetate for monoterpene esters. Lower capacity
factors (k) were observed for sesquiterpene hydrocarbons, monoterpene hydrocarbons, alcohols, and esters on the SLB-IL59 column compared to the WAX column.
Comparable k values were observed for monoterpene aldehydes on both compared
phases. When the SLB-IL59 column was evaluated for the analysis of lemon essential
oil, all the 41 components of the oil were separated and could be identified. However, neryl acetate and β-bisabolene coeluted on the WAX column, and p-cymene,
limonene, 1,8-cineole, and (Z)-β-ocimene coeluted on the 5% PDMS column. This
shows the overall better performance of the SLB-IL59 column in the separation of
lemon essential oil compared to polar WAX and nonpolar phases.
Furthermore, commercial IL columns were examined for the analyses of a 29
allergen mixture and the performance was compared to the OV-1701 column [105].
The SLB-IL76 column was not a good choice for the analysis because the separation resulted in broad peaks with low efficiency. The highly polar SLB-IL100 and
111 columns showed lower retention of volatile, nonpolar components. The SLBIL59 column showed a higher average peak width compared to the other columns.
SLB-IL61 column performed better in the separation of alcohol components. The
separation capability of IL columns was determined by calculating the separation
measure value (s) [105, 106].
s =
t B
t A
dt
σ
(6.5)
σ is the peak width and the term s defined as the number of consecutive nonoverlapping σ intervals within an arbitrary time interval (t B − t A ). The separation
measure of a time interval is the number of adjacent non-overlapping σ -slots in it
or the number of consecutive non-overlapping σ-intervals within an arbitrary time
interval. A higher separation capacity was observed for the IL columns compared to
conventional columns (OV-1701:1582) and the capacity increased from IL-59 (1516)
to IL82 (1787). This highlighted the ability of IL columns to separate a greater number
of compounds.
M. Talebi et al.
SLB-IL59 column have similar polarities, but they showed complimentary selectivities for (Z)-β-ocimene and 1,8-cineole. All four test compounds were separated
with better resolution on the SLB-IL59 column compared to the 5% phenyl PDMS
column. Also, a big difference in the elution order was observed on the two phases;
on 5% phenyl PDMS, the elution order was p-cymene < limonene < (Z)-β-ocimene
< 1,8-cineole, while on SLB-IL59 the order was limonene < (Z)-β-ocimene < 1,8cineole < p-cymene. Peak symmetry and capacity factors (k) of the IL and wax
columns were evaluated by using different test compounds representing a specific
class of compounds: limonene for monoterpene hydrocarbons, linalool for monoterpene alcohols, (E)-caryophyllene for sesquiterpene hydrocarbons, neral and geranial
for monoterpene aldehydes, and neryl acetate for monoterpene esters. Lower capacity
factors (k) were observed for sesquiterpene hydrocarbons, monoterpene hydrocarbons, alcohols, and esters on the SLB-IL59 column compared to the WAX column.
Comparable k values were observed for monoterpene aldehydes on both compared
phases. When the SLB-IL59 column was evaluated for the analysis of lemon essential
oil, all the 41 components of the oil were separated and could be identified. However, neryl acetate and β-bisabolene coeluted on the WAX column, and p-cymene,
limonene, 1,8-cineole, and (Z)-β-ocimene coeluted on the 5% PDMS column. This
shows the overall better performance of the SLB-IL59 column in the separation of
lemon essential oil compared to polar WAX and nonpolar phases.
Furthermore, commercial IL columns were examined for the analyses of a 29
allergen mixture and the performance was compared to the OV-1701 column [105].
The SLB-IL76 column was not a good choice for the analysis because the separation resulted in broad peaks with low efficiency. The highly polar SLB-IL100 and
111 columns showed lower retention of volatile, nonpolar components. The SLBIL59 column showed a higher average peak width compared to the other columns.
SLB-IL61 column performed better in the separation of alcohol components. The
separation capability of IL columns was determined by calculating the separation
measure value (s) [105, 106].
s =
t B
t A
dt
σ
(6.5)
σ is the peak width and the term s defined as the number of consecutive nonoverlapping σ intervals within an arbitrary time interval (t B − t A ). The separation
measure of a time interval is the number of adjacent non-overlapping σ -slots in it
or the number of consecutive non-overlapping σ-intervals within an arbitrary time
interval. A higher separation capacity was observed for the IL columns compared to
conventional columns (OV-1701:1582) and the capacity increased from IL-59 (1516)
to IL82 (1787). This highlighted the ability of IL columns to separate a greater number
of compounds.