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An HPLC column has a non-polar stationary\' phase (\"reverse phase\" column). A

ID: 521801 • Letter: A

Question

An HPLC column has a non-polar stationary' phase ("reverse phase" column). A relatively polar mobile phase is used to elute the compounds in a mixture. Show the expected elution order for these compounds, based on their affinities for the stationary and mobile phases. (Use the compound code designations A, B, C and D to make it easier) (A) HOOC-CH_2-CH_2-COOH (butane dioxin acid) (B) CH_3-CH_2-CH_2-CH_2-OH (1-butanol) (C) CH_3-CH_2-CH_2-CH_2-CH_3 (pentane) (D) CH_3-CH_2-O-CH_2-CH_3 (diethyl ether) First to elute: 2^nd to elute: _____ 3^rd to elute: _____ last: _____

Explanation / Answer

In reverse phase column HPLC Polar compound elute first and non polar compound elute last

for the given compunds A dioic acid highly polar compound elute first

after A ; n-butanol (B)(second elute ) is polar so elute next, then C diethyl ether 3rd elute and n-Pentane last elute (n pentane highly non polar)