Compared to Figure , the elution order of model acids followed the same C and DBE distribution trends corresponding to the three oil fractions. Carboxylic acid retention increased by increasing the number of aromatic rings and carbon sidechain (benzoic < 4-phenyl butyric < 1-pyreneacetic acid). A labeled bromine phenyl group also improved the separation of aliphatic carboxylic acids, such as butyric and octanoic acids, which otherwise can be challenging to adequately retain in reverse phase LC. Overall, the biphenyl LC column features selectivity to aromatic and moderately polar analytes by π-π interactions. It thus benefits the carboxylic-BNMA derivatives containing the bromine phenyl group(s). The LC separation has met our expectations to simplify the sample matrix and improve selectivity for derivatives.