Indicate which of the following mobile phases is the strongest for normal phase
ID: 800769 • Letter: I
Question
Indicate which of the following mobile phases is the strongest for normal phase HPLC? Strongest for reverse phase HPLC? (Write "normal" or "reverse" underneath your two choices.)
20% ethanol/80 % water 20% ethanol/ 80% hexane 100 % hexane
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(0.4 pts) Write 1st, 2nd, 3rd, 4th, underneath the following compounds to indicate their order of elution from a reversed phase liquid chromatographic column.
OH OH
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HOOC-CH2CHCH3 CH3CH2CH2CH2CH3 HOOC-CH2CH2CH3 CH3CH2CHCH3
Explanation / Answer
1) 20% ethanol 80% water ------ strongest for reverse phase
2) 20% ethanol and 80% hexane ----------- strongest for normal phase
the order is
elute first HOOC-CH2CH(OH)CH3 > HOOC-CH2CH2CH3 > CH3CH2(OH)CHCH3 > CH2CH2CH2CH2CH2CH3
CH2CH2CH2CH2CH2CH3 elutes last