On Conditions of Purification by Solid Phase Extraction in GC-MS Determination of 15 Kinds of Nitrobenzenes in Water and Sediments

It the GC-MS determination of 15 nitrobenzenes (NB′s) in samples of water and sediments, a comparative study on the choice of SPE columns (among the columns of Florida florisil, silica gel, C18 and PEP) and of composition of mixed eluants was made. It was found that: ① all the 4 SPE columns were feasible for purification of the 15 NB′s; ② similar elution efficiencies and recoveries of purification on the SPE columns (besides PEP column) were obtained by using mixed eluants with dichloromethane (DCM) or with n-hexane (NHX) as the main component, hence either pure DCM or mixtures of DCM-NHX(9+1), DCM-acetone (or ethyl acetate) (9+1) and NHX-acetone (or ethyl acetate) (9+1) could be selected as eluant; ③ for use with PEP column, pure NHX could be used in the absence of interference of moisture, and mixtures of NHX-acetone (or ethyl acetate) (9+1) as well as NHX-DCM (9+1) could be used in the presence of interference of moisture. Required recovery of the 15 NB′s was attained by elution with 10 mL of each of the above mentioned eluants.