Solvents with different polarities are also mixed and adjusted at appropriate
ratios to adjust the polarity of solvent. The order outlined above for solvent polarity
is also typically followed for the emission strength of commonly used solvents.
(1) Separation and Purification Process
Adsorbent is evenly packed in an empty tube (column) made of suitably sized glass.
The specimen is adsorbed in the upper portion of the column, with separation
occurring as different adsorption bands are forms sequentially with suitable solvents. Low-polarity solvents are used initially, with polarity gradually increased to
isolate substances.
In the case of emissions in the author’s laboratory, hexane and ethyl acetate are
used as solvents with a silica open column. Polarity is altered in order of mixed
solvents (hexane and ethyl acetate mixed at ratios of 100:1, 90:10, 70:30, 50:50,
30:70, 10:90, and 1:100), followed by emission with a 50:50 solvent mixture of
chloroform and methanol.
B. Partition Column Chromatography
Because partition column chromatography involves separation according to solvency differences in the stationary and mobile phases adsorbed to the adsorbent,
solvency must be considered rather than sample polarity when choosing stationary
and mobile phases. This approach is mainly used when separating out highly polar
hydrophilic substances (Whelan 2001).
For the stationary phase, a chemically bonded filler is used combining
hydrophobic bases (octadecyl, ODS, C 18 ; octyl, C 8 ) with hydrophilic ones
(aminopropyl, cyanopropyl, nitrophenyl). For the mobile phase, mobile solvents
with heavy polarity such as water and methanol are often used, and two or more
mixed solvents are frequently used in combination.
The emission approach used in the author’s laboratory involves a reverse ODS
open column in which water (tertiary distilled water) and methanol are used as
solvents and polarity is altered along the sequence of the solvent mixture (water and
ethanol mixture ratios of 100:1, 90:10, 70:30, 50:50, 30:70, 10:90, and 1:100).
C. Thin Layer Chromatography
In thin layer chromatography (TLC), the movement distance on the TLC plate
changes according to the different partitions between the stationary phase (adsorbent surface) and mobile phase (solvent). Because each substance exhibits a different system of movement in the composition of a particular solvent, similarity or
equivalence in distance serves as an indicator showing that the substance is identical (IUPAC 1997; Stoddard et al. 2007).
A typical method of chromatography involves manipulating the sample with a
mobile layer of solvent on a thin membrane surface made with plaster and an
10.2 Researching Natural Marine Substances
357
ratios to adjust the polarity of solvent. The order outlined above for solvent polarity
is also typically followed for the emission strength of commonly used solvents.
(1) Separation and Purification Process
Adsorbent is evenly packed in an empty tube (column) made of suitably sized glass.
The specimen is adsorbed in the upper portion of the column, with separation
occurring as different adsorption bands are forms sequentially with suitable solvents. Low-polarity solvents are used initially, with polarity gradually increased to
isolate substances.
In the case of emissions in the author’s laboratory, hexane and ethyl acetate are
used as solvents with a silica open column. Polarity is altered in order of mixed
solvents (hexane and ethyl acetate mixed at ratios of 100:1, 90:10, 70:30, 50:50,
30:70, 10:90, and 1:100), followed by emission with a 50:50 solvent mixture of
chloroform and methanol.
B. Partition Column Chromatography
Because partition column chromatography involves separation according to solvency differences in the stationary and mobile phases adsorbed to the adsorbent,
solvency must be considered rather than sample polarity when choosing stationary
and mobile phases. This approach is mainly used when separating out highly polar
hydrophilic substances (Whelan 2001).
For the stationary phase, a chemically bonded filler is used combining
hydrophobic bases (octadecyl, ODS, C 18 ; octyl, C 8 ) with hydrophilic ones
(aminopropyl, cyanopropyl, nitrophenyl). For the mobile phase, mobile solvents
with heavy polarity such as water and methanol are often used, and two or more
mixed solvents are frequently used in combination.
The emission approach used in the author’s laboratory involves a reverse ODS
open column in which water (tertiary distilled water) and methanol are used as
solvents and polarity is altered along the sequence of the solvent mixture (water and
ethanol mixture ratios of 100:1, 90:10, 70:30, 50:50, 30:70, 10:90, and 1:100).
C. Thin Layer Chromatography
In thin layer chromatography (TLC), the movement distance on the TLC plate
changes according to the different partitions between the stationary phase (adsorbent surface) and mobile phase (solvent). Because each substance exhibits a different system of movement in the composition of a particular solvent, similarity or
equivalence in distance serves as an indicator showing that the substance is identical (IUPAC 1997; Stoddard et al. 2007).
A typical method of chromatography involves manipulating the sample with a
mobile layer of solvent on a thin membrane surface made with plaster and an
10.2 Researching Natural Marine Substances
357