Chapter 6 HPLC

HPLC methods include

• liquid/liquid (partition) chromatography

• liquid/solid (adsorption) chromatography

• ion exchange nd size exclusion chromatography

• all of the option correct

The substance in the mixture that has the greatest affinity for the mobile phase will travel

• fastest
• slowest

Which of the following can be used to find the concentration of a substance in HPLC

• R_f value
• R_t value
• peak area
• peak width

What two properties affect the R_t of a compound?
I Size/weight
II Polarity
III melting point

• I only
• II only
• III only
• I and II

In order to compare to chromatograms what must be kept the same?

• stationary  phase
• mobile phase
• temperature
• all of the above

Based on a normal chromatography, the stationary phase is polar.

• TRUE

• FALSE

• Depends on the substance

What does 'normal phase' means?

• Polarity of the mobile phase is higher than stationary phase

• Both stationary and mobile phase have the same polarity

• Polarity of the stationary phase is higher than mobile phase

Which one of these do not associate with the HPLC component?

• UV detector

• Pump

• Degasser

• Atomizer

Choose the wrong characteristics of the eluent that can be used in the HPLC

• Must be pure

• Can be used without degassing

• Must complied to HPLC standard

• May have constant or gradient polarity

Choose the wrong statement regarding the column.

• Usually made of stainless steel material

• Packing materials commonly used are silica or resin

• Longer column will give longer time for the mixture to separate and thus gives better resolution

• Higher column ID can provide higher separation sensitivity