Samples were analyzed on an Agilent 1260 UHPLC coupled with DAD and an Agilent 6460 The quantitative analysis of benzylsuccinate was conducted using a DAD detector at 210 nm and external calibration (Fig. ) for samples diluted 1:1 with acetonitrile. This method was used for the determination of enzyme activity with toluene and d8-toluene.