Planar chromatography

The advantage of thin-layer chromatography over paper chromatography is ...............

• more efficient separation

• less expensive

• does not require stationary phase

• can be run ascending

What mechanism of separation occurs in paper chromatography?

• Adsorption

• Partition

• Size-exclusion

• Ion exchange

Stationary phase in paper chromatography is.............

• Silica

• Modified silica

• Cellulose

• Water

A less polar analyte will have a lower ......... when separated with unmodified silica as the stationary phase

• retention

• migration

• retardation factor

• distance from elution start point

To improve separation resolution, the following can be performed, EXCEPT......

• two-dimensional elution

• eluent modification

• modifying the stationary phase

• selecting more sensitive spraying reagent

The following are advantages of a concentration zone, EXCEPT.......

• uniform elution start point

• arbitrary elution start point

• producing tight band

• efficient separation

The following are the characteristics of high-performance thin layer chromatography (HPTLC), EXCEPT.....

• smaller particle size

• more efficient separation

• lower sample consumption

• higher plate height

When observed under UV 254 nm, a dark spot on a silica gel GF254 means..................

• the analyte gives off fluorescence at 254 nm

• the analyte absorbs light at 254 nm

• the plate emits light at 254 nm

• the analyte enhances plate emission at 254 nm

Which of the following solvent will give the smallest spot when used on a silica plate?

• chloroform

• ethanol

• water

• hexane

Spots in TLC can be located by the following methods, EXCEPT.....

• Spraying reagent

• Inspection under UV light

• Scanning densitometry

• 2D elution